test IDE of sh2007 #4

mitake · 2012-09-05T00:55:47Z

No description provided.

On architectures where cputime_t is 64 bit type, is possible to trigger divide by zero on do_div(temp, (__force u32) total) line, if total is a non zero number but has lower 32 bit's zeroed. Removing casting is not a good solution since some do_div() implementations do cast to u32 internally. This problem can be triggered in practice on very long lived processes: PID: 2331 TASK: ffff880472814b00 CPU: 2 COMMAND: "oraagent.bin" #0 [ffff880472a51b70] machine_kexec at ffffffff8103214b #1 [ffff880472a51bd0] crash_kexec at ffffffff810b91c2 #2 [ffff880472a51ca0] oops_end at ffffffff814f0b00 #3 [ffff880472a51cd0] die at ffffffff8100f26b #4 [ffff880472a51d00] do_trap at ffffffff814f03f4 #5 [ffff880472a51d60] do_divide_error at ffffffff8100cfff torvalds#6 [ffff880472a51e00] divide_error at ffffffff8100be7b [exception RIP: thread_group_times+0x56] RIP: ffffffff81056a16 RSP: ffff880472a51eb8 RFLAGS: 00010046 RAX: bc3572c9fe12d194 RBX: ffff880874150800 RCX: 0000000110266fad RDX: 0000000000000000 RSI: ffff880472a51eb8 RDI: 001038ae7d9633dc RBP: ffff880472a51ef8 R8: 00000000b10a3a64 R9: ffff880874150800 R10: 00007fcba27ab680 R11: 0000000000000202 R12: ffff880472a51f08 R13: ffff880472a51f10 R14: 0000000000000000 R15: 0000000000000007 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 torvalds#7 [ffff880472a51f00] do_sys_times at ffffffff8108845d torvalds#8 [ffff880472a51f40] sys_times at ffffffff81088524 torvalds#9 [ffff880472a51f80] system_call_fastpath at ffffffff8100b0f2 RIP: 0000003808caac3a RSP: 00007fcba27ab6d8 RFLAGS: 00000202 RAX: 0000000000000064 RBX: ffffffff8100b0f2 RCX: 0000000000000000 RDX: 00007fcba27ab6e0 RSI: 000000000076d58e RDI: 00007fcba27ab6e0 RBP: 00007fcba27ab700 R8: 0000000000000020 R9: 000000000000091b R10: 00007fcba27ab680 R11: 0000000000000202 R12: 00007fff9ca41940 R13: 0000000000000000 R14: 00007fcba27ac9c0 R15: 00007fff9ca41940 ORIG_RAX: 0000000000000064 CS: 0033 SS: 002b Cc: [email protected] Signed-off-by: Stanislaw Gruszka <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]>

Each page mapped in a process's address space must be correctly accounted for in _mapcount. Normally the rules for this are straightforward but hugetlbfs page table sharing is different. The page table pages at the PMD level are reference counted while the mapcount remains the same. If this accounting is wrong, it causes bugs like this one reported by Larry Woodman: kernel BUG at mm/filemap.c:135! invalid opcode: 0000 [#1] SMP CPU 22 Modules linked in: bridge stp llc sunrpc binfmt_misc dcdbas microcode pcspkr acpi_pad acpi] Pid: 18001, comm: mpitest Tainted: G W 3.3.0+ #4 Dell Inc. PowerEdge R620/07NDJ2 RIP: 0010:[<ffffffff8112cfed>] [<ffffffff8112cfed>] __delete_from_page_cache+0x15d/0x170 Process mpitest (pid: 18001, threadinfo ffff880428972000, task ffff880428b5cc20) Call Trace: delete_from_page_cache+0x40/0x80 truncate_hugepages+0x115/0x1f0 hugetlbfs_evict_inode+0x18/0x30 evict+0x9f/0x1b0 iput_final+0xe3/0x1e0 iput+0x3e/0x50 d_kill+0xf8/0x110 dput+0xe2/0x1b0 __fput+0x162/0x240 During fork(), copy_hugetlb_page_range() detects if huge_pte_alloc() shared page tables with the check dst_pte == src_pte. The logic is if the PMD page is the same, they must be shared. This assumes that the sharing is between the parent and child. However, if the sharing is with a different process entirely then this check fails as in this diagram: parent | ------------>pmd src_pte----------> data page ^ other--------->pmd--------------------| ^ child-----------| dst_pte For this situation to occur, it must be possible for Parent and Other to have faulted and failed to share page tables with each other. This is possible due to the following style of race. PROC A PROC B copy_hugetlb_page_range copy_hugetlb_page_range src_pte == huge_pte_offset src_pte == huge_pte_offset !src_pte so no sharing !src_pte so no sharing (time passes) hugetlb_fault hugetlb_fault huge_pte_alloc huge_pte_alloc huge_pmd_share huge_pmd_share LOCK(i_mmap_mutex) find nothing, no sharing UNLOCK(i_mmap_mutex) LOCK(i_mmap_mutex) find nothing, no sharing UNLOCK(i_mmap_mutex) pmd_alloc pmd_alloc LOCK(instantiation_mutex) fault UNLOCK(instantiation_mutex) LOCK(instantiation_mutex) fault UNLOCK(instantiation_mutex) These two processes are not poing to the same data page but are not sharing page tables because the opportunity was missed. When either process later forks, the src_pte == dst pte is potentially insufficient. As the check falls through, the wrong PTE information is copied in (harmless but wrong) and the mapcount is bumped for a page mapped by a shared page table leading to the BUG_ON. This patch addresses the issue by moving pmd_alloc into huge_pmd_share which guarantees that the shared pud is populated in the same critical section as pmd. This also means that huge_pte_offset test in huge_pmd_share is serialized correctly now which in turn means that the success of the sharing will be higher as the racing tasks see the pud and pmd populated together. Race identified and changelog written mostly by Mel Gorman. {[email protected]: attempt to make the huge_pmd_share() comment comprehensible, clean up coding style] Reported-by: Larry Woodman <[email protected]> Tested-by: Larry Woodman <[email protected]> Reviewed-by: Mel Gorman <[email protected]> Signed-off-by: Michal Hocko <[email protected]> Reviewed-by: Rik van Riel <[email protected]> Cc: David Gibson <[email protected]> Cc: Ken Chen <[email protected]> Cc: Cong Wang <[email protected]> Cc: Hillf Danton <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

If SMP fails, we should always cancel security_timer delayed work. Otherwise, security_timer function may run after l2cap_conn object has been freed. This patch fixes the following warning reported by ODEBUG: WARNING: at lib/debugobjects.c:261 debug_print_object+0x7c/0x8d() Hardware name: Bochs ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x27 Modules linked in: btusb bluetooth Pid: 440, comm: kworker/u:2 Not tainted 3.5.0-rc1+ #4 Call Trace: [<ffffffff81174600>] ? free_obj_work+0x4a/0x7f [<ffffffff81023eb8>] warn_slowpath_common+0x7e/0x97 [<ffffffff81023f65>] warn_slowpath_fmt+0x41/0x43 [<ffffffff811746b1>] debug_print_object+0x7c/0x8d [<ffffffff810394f0>] ? __queue_work+0x241/0x241 [<ffffffff81174fdd>] debug_check_no_obj_freed+0x92/0x159 [<ffffffff810ac08e>] slab_free_hook+0x6f/0x77 [<ffffffffa0019145>] ? l2cap_conn_del+0x148/0x157 [bluetooth] [<ffffffff810ae408>] kfree+0x59/0xac [<ffffffffa0019145>] l2cap_conn_del+0x148/0x157 [bluetooth] [<ffffffffa001b9a2>] l2cap_recv_frame+0xa77/0xfa4 [bluetooth] [<ffffffff810592f9>] ? trace_hardirqs_on_caller+0x112/0x1ad [<ffffffffa001c86c>] l2cap_recv_acldata+0xe2/0x264 [bluetooth] [<ffffffffa0002b2f>] hci_rx_work+0x235/0x33c [bluetooth] [<ffffffff81038dc3>] ? process_one_work+0x126/0x2fe [<ffffffff81038e22>] process_one_work+0x185/0x2fe [<ffffffff81038dc3>] ? process_one_work+0x126/0x2fe [<ffffffff81059f2e>] ? lock_acquired+0x1b5/0x1cf [<ffffffffa00028fa>] ? le_scan_work+0x11d/0x11d [bluetooth] [<ffffffff81036fb6>] ? spin_lock_irq+0x9/0xb [<ffffffff81039209>] worker_thread+0xcf/0x175 [<ffffffff8103913a>] ? rescuer_thread+0x175/0x175 [<ffffffff8103cfe0>] kthread+0x95/0x9d [<ffffffff812c5054>] kernel_threadi_helper+0x4/0x10 [<ffffffff812c36b0>] ? retint_restore_args+0x13/0x13 [<ffffffff8103cf4b>] ? flush_kthread_worker+0xdb/0xdb [<ffffffff812c5050>] ? gs_change+0x13/0x13 This bug can be reproduced using hctool lecc or l2test tools and bluetoothd not running. Signed-off-by: Andre Guedes <[email protected]> Signed-off-by: Gustavo Padovan <[email protected]>

Fixes following lockdep splat : [ 1614.734896] ============================================= [ 1614.734898] [ INFO: possible recursive locking detected ] [ 1614.734901] 3.6.0-rc3+ torvalds#782 Not tainted [ 1614.734903] --------------------------------------------- [ 1614.734905] swapper/11/0 is trying to acquire lock: [ 1614.734907] (slock-AF_INET){+.-...}, at: [<ffffffffa0209d72>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [ 1614.734920] [ 1614.734920] but task is already holding lock: [ 1614.734922] (slock-AF_INET){+.-...}, at: [<ffffffff815fce23>] tcp_v4_err+0x163/0x6b0 [ 1614.734932] [ 1614.734932] other info that might help us debug this: [ 1614.734935] Possible unsafe locking scenario: [ 1614.734935] [ 1614.734937] CPU0 [ 1614.734938] ---- [ 1614.734940] lock(slock-AF_INET); [ 1614.734943] lock(slock-AF_INET); [ 1614.734946] [ 1614.734946] *** DEADLOCK *** [ 1614.734946] [ 1614.734949] May be due to missing lock nesting notation [ 1614.734949] [ 1614.734952] 7 locks held by swapper/11/0: [ 1614.734954] #0: (rcu_read_lock){.+.+..}, at: [<ffffffff81592801>] __netif_receive_skb+0x251/0xd00 [ 1614.734964] #1: (rcu_read_lock){.+.+..}, at: [<ffffffff815d319c>] ip_local_deliver_finish+0x4c/0x4e0 [ 1614.734972] #2: (rcu_read_lock){.+.+..}, at: [<ffffffff8160d116>] icmp_socket_deliver+0x46/0x230 [ 1614.734982] #3: (slock-AF_INET){+.-...}, at: [<ffffffff815fce23>] tcp_v4_err+0x163/0x6b0 [ 1614.734989] #4: (rcu_read_lock){.+.+..}, at: [<ffffffff815da240>] ip_queue_xmit+0x0/0x680 [ 1614.734997] #5: (rcu_read_lock_bh){.+....}, at: [<ffffffff815d9925>] ip_finish_output+0x135/0x890 [ 1614.735004] torvalds#6: (rcu_read_lock_bh){.+....}, at: [<ffffffff81595680>] dev_queue_xmit+0x0/0xe00 [ 1614.735012] [ 1614.735012] stack backtrace: [ 1614.735016] Pid: 0, comm: swapper/11 Not tainted 3.6.0-rc3+ torvalds#782 [ 1614.735018] Call Trace: [ 1614.735020] <IRQ> [<ffffffff810a50ac>] __lock_acquire+0x144c/0x1b10 [ 1614.735033] [<ffffffff810a334b>] ? check_usage+0x9b/0x4d0 [ 1614.735037] [<ffffffff810a6762>] ? mark_held_locks+0x82/0x130 [ 1614.735042] [<ffffffff810a5df0>] lock_acquire+0x90/0x200 [ 1614.735047] [<ffffffffa0209d72>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [ 1614.735051] [<ffffffff810a69ad>] ? trace_hardirqs_on+0xd/0x10 [ 1614.735060] [<ffffffff81749b31>] _raw_spin_lock+0x41/0x50 [ 1614.735065] [<ffffffffa0209d72>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [ 1614.735069] [<ffffffffa0209d72>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [ 1614.735075] [<ffffffffa014f7f2>] l2tp_eth_dev_xmit+0x32/0x60 [l2tp_eth] [ 1614.735079] [<ffffffff81595112>] dev_hard_start_xmit+0x502/0xa70 [ 1614.735083] [<ffffffff81594c6e>] ? dev_hard_start_xmit+0x5e/0xa70 [ 1614.735087] [<ffffffff815957c1>] ? dev_queue_xmit+0x141/0xe00 [ 1614.735093] [<ffffffff815b622e>] sch_direct_xmit+0xfe/0x290 [ 1614.735098] [<ffffffff81595865>] dev_queue_xmit+0x1e5/0xe00 [ 1614.735102] [<ffffffff81595680>] ? dev_hard_start_xmit+0xa70/0xa70 [ 1614.735106] [<ffffffff815b4daa>] ? eth_header+0x3a/0xf0 [ 1614.735111] [<ffffffff8161d33e>] ? fib_get_table+0x2e/0x280 [ 1614.735117] [<ffffffff8160a7e2>] arp_xmit+0x22/0x60 [ 1614.735121] [<ffffffff8160a863>] arp_send+0x43/0x50 [ 1614.735125] [<ffffffff8160b82f>] arp_solicit+0x18f/0x450 [ 1614.735132] [<ffffffff8159d9da>] neigh_probe+0x4a/0x70 [ 1614.735137] [<ffffffff815a191a>] __neigh_event_send+0xea/0x300 [ 1614.735141] [<ffffffff815a1c93>] neigh_resolve_output+0x163/0x260 [ 1614.735146] [<ffffffff815d9cf5>] ip_finish_output+0x505/0x890 [ 1614.735150] [<ffffffff815d9925>] ? ip_finish_output+0x135/0x890 [ 1614.735154] [<ffffffff815dae79>] ip_output+0x59/0xf0 [ 1614.735158] [<ffffffff815da1cd>] ip_local_out+0x2d/0xa0 [ 1614.735162] [<ffffffff815da403>] ip_queue_xmit+0x1c3/0x680 [ 1614.735165] [<ffffffff815da240>] ? ip_local_out+0xa0/0xa0 [ 1614.735172] [<ffffffff815f4402>] tcp_transmit_skb+0x402/0xa60 [ 1614.735177] [<ffffffff815f5a11>] tcp_retransmit_skb+0x1a1/0x620 [ 1614.735181] [<ffffffff815f7e93>] tcp_retransmit_timer+0x393/0x960 [ 1614.735185] [<ffffffff815fce23>] ? tcp_v4_err+0x163/0x6b0 [ 1614.735189] [<ffffffff815fd317>] tcp_v4_err+0x657/0x6b0 [ 1614.735194] [<ffffffff8160d116>] ? icmp_socket_deliver+0x46/0x230 [ 1614.735199] [<ffffffff8160d19e>] icmp_socket_deliver+0xce/0x230 [ 1614.735203] [<ffffffff8160d116>] ? icmp_socket_deliver+0x46/0x230 [ 1614.735208] [<ffffffff8160d464>] icmp_unreach+0xe4/0x2c0 [ 1614.735213] [<ffffffff8160e520>] icmp_rcv+0x350/0x4a0 [ 1614.735217] [<ffffffff815d3285>] ip_local_deliver_finish+0x135/0x4e0 [ 1614.735221] [<ffffffff815d319c>] ? ip_local_deliver_finish+0x4c/0x4e0 [ 1614.735225] [<ffffffff815d3ffa>] ip_local_deliver+0x4a/0x90 [ 1614.735229] [<ffffffff815d37b7>] ip_rcv_finish+0x187/0x730 [ 1614.735233] [<ffffffff815d425d>] ip_rcv+0x21d/0x300 [ 1614.735237] [<ffffffff81592a1b>] __netif_receive_skb+0x46b/0xd00 [ 1614.735241] [<ffffffff81592801>] ? __netif_receive_skb+0x251/0xd00 [ 1614.735245] [<ffffffff81593368>] process_backlog+0xb8/0x180 [ 1614.735249] [<ffffffff81593cf9>] net_rx_action+0x159/0x330 [ 1614.735257] [<ffffffff810491f0>] __do_softirq+0xd0/0x3e0 [ 1614.735264] [<ffffffff8109ed24>] ? tick_program_event+0x24/0x30 [ 1614.735270] [<ffffffff8175419c>] call_softirq+0x1c/0x30 [ 1614.735278] [<ffffffff8100425d>] do_softirq+0x8d/0xc0 [ 1614.735282] [<ffffffff8104983e>] irq_exit+0xae/0xe0 [ 1614.735287] [<ffffffff8175494e>] smp_apic_timer_interrupt+0x6e/0x99 [ 1614.735291] [<ffffffff81753a1c>] apic_timer_interrupt+0x6c/0x80 [ 1614.735293] <EOI> [<ffffffff810a14ad>] ? trace_hardirqs_off+0xd/0x10 [ 1614.735306] [<ffffffff81336f85>] ? intel_idle+0xf5/0x150 [ 1614.735310] [<ffffffff81336f7e>] ? intel_idle+0xee/0x150 [ 1614.735317] [<ffffffff814e6ea9>] cpuidle_enter+0x19/0x20 [ 1614.735321] [<ffffffff814e7538>] cpuidle_idle_call+0xa8/0x630 [ 1614.735327] [<ffffffff8100c1ba>] cpu_idle+0x8a/0xe0 [ 1614.735333] [<ffffffff8173762e>] start_secondary+0x220/0x222 Signed-off-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]>

Cancel work of the xfs_sync_worker before teardown of the log in xfs_unmountfs. This prevents occasional crashes on unmount like so: PID: 21602 TASK: ee9df060 CPU: 0 COMMAND: "kworker/0:3" #0 [c5377d28] crash_kexec at c0292c94 #1 [c5377d80] oops_end at c07090c2 #2 [c5377d98] no_context at c06f614e #3 [c5377dbc] __bad_area_nosemaphore at c06f6281 #4 [c5377df4] bad_area_nosemaphore at c06f629b #5 [c5377e00] do_page_fault at c070b0cb torvalds#6 [c5377e7c] error_code (via page_fault) at c070892c EAX: f300c6a8 EBX: f300c6a8 ECX: 000000c0 EDX: 000000c0 EBP: c5377ed0 DS: 007b ESI: 00000000 ES: 007b EDI: 00000001 GS: ffffad20 CS: 0060 EIP: c0481ad0 ERR: ffffffff EFLAGS: 00010246 torvalds#7 [c5377eb0] atomic64_read_cx8 at c0481ad0 torvalds#8 [c5377ebc] xlog_assign_tail_lsn_locked at f7cc7c6e [xfs] torvalds#9 [c5377ed4] xfs_trans_ail_delete_bulk at f7ccd520 [xfs] torvalds#10 [c5377f0c] xfs_buf_iodone at f7ccb602 [xfs] torvalds#11 [c5377f24] xfs_buf_do_callbacks at f7cca524 [xfs] torvalds#12 [c5377f30] xfs_buf_iodone_callbacks at f7cca5da [xfs] torvalds#13 [c5377f4c] xfs_buf_iodone_work at f7c718d0 [xfs] torvalds#14 [c5377f58] process_one_work at c024ee4c torvalds#15 [c5377f98] worker_thread at c024f43d torvalds#16 [c5377fb] kthread at c025326b torvalds#17 [c5377fe8] kernel_thread_helper at c070e834 PID: 26653 TASK: e79143b0 CPU: 3 COMMAND: "umount" #0 [cde0fda0] __schedule at c0706595 #1 [cde0fe28] schedule at c0706b89 #2 [cde0fe30] schedule_timeout at c0705600 #3 [cde0fe94] __down_common at c0706098 #4 [cde0fec8] __down at c0706122 #5 [cde0fed0] down at c025936f torvalds#6 [cde0fee0] xfs_buf_lock at f7c7131d [xfs] torvalds#7 [cde0ff00] xfs_freesb at f7cc2236 [xfs] torvalds#8 [cde0ff10] xfs_fs_put_super at f7c80f21 [xfs] torvalds#9 [cde0ff1c] generic_shutdown_super at c0333d7a torvalds#10 [cde0ff38] kill_block_super at c0333e0f torvalds#11 [cde0ff48] deactivate_locked_super at c0334218 torvalds#12 [cde0ff58] deactivate_super at c033495d torvalds#13 [cde0ff68] mntput_no_expire at c034bc13 torvalds#14 [cde0ff7c] sys_umount at c034cc69 torvalds#15 [cde0ffa0] sys_oldumount at c034ccd4 torvalds#16 [cde0ffb0] system_call at c0707e66 commit 11159a0 added this to xfs_log_unmount and needs to be cleaned up at a later date. Signed-off-by: Ben Myers <[email protected]> Reviewed-by: Dave Chinner <[email protected]> Reviewed-by: Mark Tinguely <[email protected]>

The next step in reducing RCU's grace-period initialization latency on large systems will make this initialization preemptible. Unfortunately, making the grace-period initialization subject to interrupts (let alone preemption) exposes the following race on systems whose rcu_node tree contains more than one node: 1. CPU 31 starts initializing the grace period, including the first leaf rcu_node structures, and is then preempted. 2. CPU 0 refers to the first leaf rcu_node structure, and notes that a new grace period has started. It passes through a quiescent state shortly thereafter, and informs the RCU core of this rite of passage. 3. CPU 0 enters an RCU read-side critical section, acquiring a pointer to an RCU-protected data item. 4. CPU 31 takes an interrupt whose handler removes the data item referenced by CPU 0 from the data structure, and registers an RCU callback in order to free it. 5. CPU 31 resumes initializing the grace period, including its own rcu_node structure. In invokes rcu_start_gp_per_cpu(), which advances all callbacks, including the one registered in #4 above, to be handled by the current grace period. 6. The remaining CPUs pass through quiescent states and inform the RCU core, but CPU 0 remains in its RCU read-side critical section, still referencing the now-removed data item. 7. The grace period completes and all the callbacks are invoked, including the one that frees the data item that CPU 0 is still referencing. Oops!!! One way to avoid this race is to remove grace-period acceleration from rcu_start_gp_per_cpu(). Now, the only reason for this acceleration was to allow CPUs bringing RCU out of idle state to have their callbacks invoked after only one grace period, rather than the two grace periods that would otherwise be required. But this acceleration does not work when RCU grace-period initialization is moved to a kthread because the CPU posting the callback is no longer necessarily the CPU that is initializing the resulting grace period. This commit therefore removes this now-pointless (and soon to be dangerous) grace-period acceleration, thus avoiding the above race. Signed-off-by: Paul E. McKenney <[email protected]>

This moves ARM over to the asm-generic/unaligned.h header. This has the benefit of better code generated especially for ARMv7 on gcc 4.7+ compilers. As Arnd Bergmann, points out: The asm-generic version uses the "struct" version for native-endian unaligned access and the "byteshift" version for the opposite endianess. The current ARM version however uses the "byteshift" implementation for both. Thanks to Nicolas Pitre for the excellent analysis: Test case: int foo (int *x) { return get_unaligned(x); } long long bar (long long *x) { return get_unaligned(x); } With the current ARM version: foo: ldrb r3, [r0, #2] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 2B], MEM[(const u8 *)x_1(D) + 2B] ldrb r1, [r0, #1] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 1B], MEM[(const u8 *)x_1(D) + 1B] ldrb r2, [r0, #0] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D)], MEM[(const u8 *)x_1(D)] mov r3, r3, asl torvalds#16 @ tmp154, MEM[(const u8 *)x_1(D) + 2B], ldrb r0, [r0, #3] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 3B], MEM[(const u8 *)x_1(D) + 3B] orr r3, r3, r1, asl torvalds#8 @, tmp155, tmp154, MEM[(const u8 *)x_1(D) + 1B], orr r3, r3, r2 @ tmp157, tmp155, MEM[(const u8 *)x_1(D)] orr r0, r3, r0, asl torvalds#24 @,, tmp157, MEM[(const u8 *)x_1(D) + 3B], bx lr @ bar: stmfd sp!, {r4, r5, r6, r7} @, mov r2, #0 @ tmp184, ldrb r5, [r0, torvalds#6] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 6B], MEM[(const u8 *)x_1(D) + 6B] ldrb r4, [r0, #5] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 5B], MEM[(const u8 *)x_1(D) + 5B] ldrb ip, [r0, #2] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 2B], MEM[(const u8 *)x_1(D) + 2B] ldrb r1, [r0, #4] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 4B], MEM[(const u8 *)x_1(D) + 4B] mov r5, r5, asl torvalds#16 @ tmp175, MEM[(const u8 *)x_1(D) + 6B], ldrb r7, [r0, #1] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 1B], MEM[(const u8 *)x_1(D) + 1B] orr r5, r5, r4, asl torvalds#8 @, tmp176, tmp175, MEM[(const u8 *)x_1(D) + 5B], ldrb r6, [r0, torvalds#7] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 7B], MEM[(const u8 *)x_1(D) + 7B] orr r5, r5, r1 @ tmp178, tmp176, MEM[(const u8 *)x_1(D) + 4B] ldrb r4, [r0, #0] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D)], MEM[(const u8 *)x_1(D)] mov ip, ip, asl torvalds#16 @ tmp188, MEM[(const u8 *)x_1(D) + 2B], ldrb r1, [r0, #3] @ zero_extendqisi2 @ MEM[(const u8 *)x_1(D) + 3B], MEM[(const u8 *)x_1(D) + 3B] orr ip, ip, r7, asl torvalds#8 @, tmp189, tmp188, MEM[(const u8 *)x_1(D) + 1B], orr r3, r5, r6, asl torvalds#24 @,, tmp178, MEM[(const u8 *)x_1(D) + 7B], orr ip, ip, r4 @ tmp191, tmp189, MEM[(const u8 *)x_1(D)] orr ip, ip, r1, asl torvalds#24 @, tmp194, tmp191, MEM[(const u8 *)x_1(D) + 3B], mov r1, r3 @, orr r0, r2, ip @ tmp171, tmp184, tmp194 ldmfd sp!, {r4, r5, r6, r7} bx lr In both cases the code is slightly suboptimal. One may wonder why wasting r2 with the constant 0 in the second case for example. And all the mov's could be folded in subsequent orr's, etc. Now with the asm-generic version: foo: ldr r0, [r0, #0] @ unaligned @,* x bx lr @ bar: mov r3, r0 @ x, x ldr r0, [r0, #0] @ unaligned @,* x ldr r1, [r3, #4] @ unaligned @, bx lr @ This is way better of course, but only because this was compiled for ARMv7. In this case the compiler knows that the hardware can do unaligned word access. This isn't that obvious for foo(), but if we remove the get_unaligned() from bar as follows: long long bar (long long *x) {return *x; } then the resulting code is: bar: ldmia r0, {r0, r1} @ x,, bx lr @ So this proves that the presumed aligned vs unaligned cases does have influence on the instructions the compiler may use and that the above unaligned code results are not just an accident. Still... this isn't fully conclusive without at least looking at the resulting assembly fron a pre ARMv6 compilation. Let's see with an ARMv5 target: foo: ldrb r3, [r0, #0] @ zero_extendqisi2 @ tmp139,* x ldrb r1, [r0, #1] @ zero_extendqisi2 @ tmp140, ldrb r2, [r0, #2] @ zero_extendqisi2 @ tmp143, ldrb r0, [r0, #3] @ zero_extendqisi2 @ tmp146, orr r3, r3, r1, asl torvalds#8 @, tmp142, tmp139, tmp140, orr r3, r3, r2, asl torvalds#16 @, tmp145, tmp142, tmp143, orr r0, r3, r0, asl torvalds#24 @,, tmp145, tmp146, bx lr @ bar: stmfd sp!, {r4, r5, r6, r7} @, ldrb r2, [r0, #0] @ zero_extendqisi2 @ tmp139,* x ldrb r7, [r0, #1] @ zero_extendqisi2 @ tmp140, ldrb r3, [r0, #4] @ zero_extendqisi2 @ tmp149, ldrb r6, [r0, #5] @ zero_extendqisi2 @ tmp150, ldrb r5, [r0, #2] @ zero_extendqisi2 @ tmp143, ldrb r4, [r0, torvalds#6] @ zero_extendqisi2 @ tmp153, ldrb r1, [r0, torvalds#7] @ zero_extendqisi2 @ tmp156, ldrb ip, [r0, #3] @ zero_extendqisi2 @ tmp146, orr r2, r2, r7, asl torvalds#8 @, tmp142, tmp139, tmp140, orr r3, r3, r6, asl torvalds#8 @, tmp152, tmp149, tmp150, orr r2, r2, r5, asl torvalds#16 @, tmp145, tmp142, tmp143, orr r3, r3, r4, asl torvalds#16 @, tmp155, tmp152, tmp153, orr r0, r2, ip, asl torvalds#24 @,, tmp145, tmp146, orr r1, r3, r1, asl torvalds#24 @,, tmp155, tmp156, ldmfd sp!, {r4, r5, r6, r7} bx lr Compared to the initial results, this is really nicely optimized and I couldn't do much better if I were to hand code it myself. Signed-off-by: Rob Herring <[email protected]> Reviewed-by: Nicolas Pitre <[email protected]> Tested-by: Thomas Petazzoni <[email protected]> Reviewed-by: Arnd Bergmann <[email protected]> Signed-off-by: Russell King <[email protected]>

It seems we need to provide ability for stacked devices to use specific lock_class_key for sch->busylock We could instead default l2tpeth tx_queue_len to 0 (no qdisc), but a user might use a qdisc anyway. (So same fixes are probably needed on non LLTX stacked drivers) Noticed while stressing L2TPV3 setup : ====================================================== [ INFO: possible circular locking dependency detected ] 3.6.0-rc3+ #788 Not tainted ------------------------------------------------------- netperf/4660 is trying to acquire lock: (l2tpsock){+.-...}, at: [<ffffffffa0208db2>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core] but task is already holding lock: (&(&sch->busylock)->rlock){+.-...}, at: [<ffffffff81596595>] dev_queue_xmit+0xd75/0xe00 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&(&sch->busylock)->rlock){+.-...}: [<ffffffff810a5df0>] lock_acquire+0x90/0x200 [<ffffffff817499fc>] _raw_spin_lock_irqsave+0x4c/0x60 [<ffffffff81074872>] __wake_up+0x32/0x70 [<ffffffff8136d39e>] tty_wakeup+0x3e/0x80 [<ffffffff81378fb3>] pty_write+0x73/0x80 [<ffffffff8136cb4c>] tty_put_char+0x3c/0x40 [<ffffffff813722b2>] process_echoes+0x142/0x330 [<ffffffff813742ab>] n_tty_receive_buf+0x8fb/0x1230 [<ffffffff813777b2>] flush_to_ldisc+0x142/0x1c0 [<ffffffff81062818>] process_one_work+0x198/0x760 [<ffffffff81063236>] worker_thread+0x186/0x4b0 [<ffffffff810694d3>] kthread+0x93/0xa0 [<ffffffff81753e24>] kernel_thread_helper+0x4/0x10 -> #0 (l2tpsock){+.-...}: [<ffffffff810a5288>] __lock_acquire+0x1628/0x1b10 [<ffffffff810a5df0>] lock_acquire+0x90/0x200 [<ffffffff817498c1>] _raw_spin_lock+0x41/0x50 [<ffffffffa0208db2>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [<ffffffffa021a802>] l2tp_eth_dev_xmit+0x32/0x60 [l2tp_eth] [<ffffffff815952b2>] dev_hard_start_xmit+0x502/0xa70 [<ffffffff815b63ce>] sch_direct_xmit+0xfe/0x290 [<ffffffff81595a05>] dev_queue_xmit+0x1e5/0xe00 [<ffffffff815d9d60>] ip_finish_output+0x3d0/0x890 [<ffffffff815db019>] ip_output+0x59/0xf0 [<ffffffff815da36d>] ip_local_out+0x2d/0xa0 [<ffffffff815da5a3>] ip_queue_xmit+0x1c3/0x680 [<ffffffff815f4192>] tcp_transmit_skb+0x402/0xa60 [<ffffffff815f4a94>] tcp_write_xmit+0x1f4/0xa30 [<ffffffff815f5300>] tcp_push_one+0x30/0x40 [<ffffffff815e6672>] tcp_sendmsg+0xe82/0x1040 [<ffffffff81614495>] inet_sendmsg+0x125/0x230 [<ffffffff81576cdc>] sock_sendmsg+0xdc/0xf0 [<ffffffff81579ece>] sys_sendto+0xfe/0x130 [<ffffffff81752c92>] system_call_fastpath+0x16/0x1b Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&sch->busylock)->rlock); lock(l2tpsock); lock(&(&sch->busylock)->rlock); lock(l2tpsock); *** DEADLOCK *** 5 locks held by netperf/4660: #0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff815e581c>] tcp_sendmsg+0x2c/0x1040 #1: (rcu_read_lock){.+.+..}, at: [<ffffffff815da3e0>] ip_queue_xmit+0x0/0x680 #2: (rcu_read_lock_bh){.+....}, at: [<ffffffff815d9ac5>] ip_finish_output+0x135/0x890 #3: (rcu_read_lock_bh){.+....}, at: [<ffffffff81595820>] dev_queue_xmit+0x0/0xe00 #4: (&(&sch->busylock)->rlock){+.-...}, at: [<ffffffff81596595>] dev_queue_xmit+0xd75/0xe00 stack backtrace: Pid: 4660, comm: netperf Not tainted 3.6.0-rc3+ #788 Call Trace: [<ffffffff8173dbf8>] print_circular_bug+0x1fb/0x20c [<ffffffff810a5288>] __lock_acquire+0x1628/0x1b10 [<ffffffff810a334b>] ? check_usage+0x9b/0x4d0 [<ffffffff810a3f44>] ? __lock_acquire+0x2e4/0x1b10 [<ffffffff810a5df0>] lock_acquire+0x90/0x200 [<ffffffffa0208db2>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [<ffffffff817498c1>] _raw_spin_lock+0x41/0x50 [<ffffffffa0208db2>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [<ffffffffa0208db2>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core] [<ffffffffa021a802>] l2tp_eth_dev_xmit+0x32/0x60 [l2tp_eth] [<ffffffff815952b2>] dev_hard_start_xmit+0x502/0xa70 [<ffffffff81594e0e>] ? dev_hard_start_xmit+0x5e/0xa70 [<ffffffff81595961>] ? dev_queue_xmit+0x141/0xe00 [<ffffffff815b63ce>] sch_direct_xmit+0xfe/0x290 [<ffffffff81595a05>] dev_queue_xmit+0x1e5/0xe00 [<ffffffff81595820>] ? dev_hard_start_xmit+0xa70/0xa70 [<ffffffff815d9d60>] ip_finish_output+0x3d0/0x890 [<ffffffff815d9ac5>] ? ip_finish_output+0x135/0x890 [<ffffffff815db019>] ip_output+0x59/0xf0 [<ffffffff815da36d>] ip_local_out+0x2d/0xa0 [<ffffffff815da5a3>] ip_queue_xmit+0x1c3/0x680 [<ffffffff815da3e0>] ? ip_local_out+0xa0/0xa0 [<ffffffff815f4192>] tcp_transmit_skb+0x402/0xa60 [<ffffffff815fa25e>] ? tcp_md5_do_lookup+0x18e/0x1a0 [<ffffffff815f4a94>] tcp_write_xmit+0x1f4/0xa30 [<ffffffff815f5300>] tcp_push_one+0x30/0x40 [<ffffffff815e6672>] tcp_sendmsg+0xe82/0x1040 [<ffffffff81614495>] inet_sendmsg+0x125/0x230 [<ffffffff81614370>] ? inet_create+0x6b0/0x6b0 [<ffffffff8157e6e2>] ? sock_update_classid+0xc2/0x3b0 [<ffffffff8157e750>] ? sock_update_classid+0x130/0x3b0 [<ffffffff81576cdc>] sock_sendmsg+0xdc/0xf0 [<ffffffff81162579>] ? fget_light+0x3f9/0x4f0 [<ffffffff81579ece>] sys_sendto+0xfe/0x130 [<ffffffff810a69ad>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff8174a0b0>] ? _raw_spin_unlock_irq+0x30/0x50 [<ffffffff810757e3>] ? finish_task_switch+0x83/0xf0 [<ffffffff810757a6>] ? finish_task_switch+0x46/0xf0 [<ffffffff81752cb7>] ? sysret_check+0x1b/0x56 [<ffffffff81752c92>] system_call_fastpath+0x16/0x1b Signed-off-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]>

Cancel work of the xfs_sync_worker before teardown of the log in xfs_unmountfs. This prevents occasional crashes on unmount like so: PID: 21602 TASK: ee9df060 CPU: 0 COMMAND: "kworker/0:3" #0 [c5377d28] crash_kexec at c0292c94 #1 [c5377d80] oops_end at c07090c2 #2 [c5377d98] no_context at c06f614e #3 [c5377dbc] __bad_area_nosemaphore at c06f6281 #4 [c5377df4] bad_area_nosemaphore at c06f629b #5 [c5377e00] do_page_fault at c070b0cb torvalds#6 [c5377e7c] error_code (via page_fault) at c070892c EAX: f300c6a8 EBX: f300c6a8 ECX: 000000c0 EDX: 000000c0 EBP: c5377ed0 DS: 007b ESI: 00000000 ES: 007b EDI: 00000001 GS: ffffad20 CS: 0060 EIP: c0481ad0 ERR: ffffffff EFLAGS: 00010246 torvalds#7 [c5377eb0] atomic64_read_cx8 at c0481ad0 torvalds#8 [c5377ebc] xlog_assign_tail_lsn_locked at f7cc7c6e [xfs] torvalds#9 [c5377ed4] xfs_trans_ail_delete_bulk at f7ccd520 [xfs] torvalds#10 [c5377f0c] xfs_buf_iodone at f7ccb602 [xfs] torvalds#11 [c5377f24] xfs_buf_do_callbacks at f7cca524 [xfs] torvalds#12 [c5377f30] xfs_buf_iodone_callbacks at f7cca5da [xfs] torvalds#13 [c5377f4c] xfs_buf_iodone_work at f7c718d0 [xfs] torvalds#14 [c5377f58] process_one_work at c024ee4c torvalds#15 [c5377f98] worker_thread at c024f43d torvalds#16 [c5377fb] kthread at c025326b torvalds#17 [c5377fe8] kernel_thread_helper at c070e834 PID: 26653 TASK: e79143b0 CPU: 3 COMMAND: "umount" #0 [cde0fda0] __schedule at c0706595 #1 [cde0fe28] schedule at c0706b89 #2 [cde0fe30] schedule_timeout at c0705600 #3 [cde0fe94] __down_common at c0706098 #4 [cde0fec8] __down at c0706122 #5 [cde0fed0] down at c025936f torvalds#6 [cde0fee0] xfs_buf_lock at f7c7131d [xfs] torvalds#7 [cde0ff00] xfs_freesb at f7cc2236 [xfs] torvalds#8 [cde0ff10] xfs_fs_put_super at f7c80f21 [xfs] torvalds#9 [cde0ff1c] generic_shutdown_super at c0333d7a torvalds#10 [cde0ff38] kill_block_super at c0333e0f torvalds#11 [cde0ff48] deactivate_locked_super at c0334218 torvalds#12 [cde0ff58] deactivate_super at c033495d torvalds#13 [cde0ff68] mntput_no_expire at c034bc13 torvalds#14 [cde0ff7c] sys_umount at c034cc69 torvalds#15 [cde0ffa0] sys_oldumount at c034ccd4 torvalds#16 [cde0ffb0] system_call at c0707e66 commit 11159a0 added this to xfs_log_unmount and needs to be cleaned up at a later date. Signed-off-by: Ben Myers <[email protected]> Reviewed-by: Dave Chinner <[email protected]> Reviewed-by: Mark Tinguely <[email protected]>

As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was added, as well as NR_syscalls in asm/unistd.h. Additionally, __sys_trace was modified to call trace_sys_enter and trace_sys_exit when appropriate. Tests #2 - #4 of "perf test" now complete successfully. Signed-off-by: Steven Walter <[email protected]> Signed-off-by: Wade Farnsworth <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Russell King <[email protected]>

If a qdisc is installed on a bonding device, its possible to get following lockdep splat under stress : ============================================= [ INFO: possible recursive locking detected ] 3.6.0+ torvalds#211 Not tainted --------------------------------------------- ping/4876 is trying to acquire lock: (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-...}, at: [<ffffffff8157a191>] dev_queue_xmit+0xe1/0x830 but task is already holding lock: (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-...}, at: [<ffffffff8157a191>] dev_queue_xmit+0xe1/0x830 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by ping/4876: #0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff815e5030>] raw_sendmsg+0x600/0xc30 #1: (rcu_read_lock_bh){.+....}, at: [<ffffffff815ba4bd>] ip_finish_output+0x12d/0x870 #2: (rcu_read_lock_bh){.+....}, at: [<ffffffff8157a0b0>] dev_queue_xmit+0x0/0x830 #3: (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-...}, at: [<ffffffff8157a191>] dev_queue_xmit+0xe1/0x830 #4: (&bond->lock){++.?..}, at: [<ffffffffa02128c1>] bond_start_xmit+0x31/0x4b0 [bonding] #5: (rcu_read_lock_bh){.+....}, at: [<ffffffff8157a0b0>] dev_queue_xmit+0x0/0x830 stack backtrace: Pid: 4876, comm: ping Not tainted 3.6.0+ torvalds#211 Call Trace: [<ffffffff810a0145>] __lock_acquire+0x715/0x1b80 [<ffffffff810a256b>] ? mark_held_locks+0x9b/0x100 [<ffffffff810a1bf2>] lock_acquire+0x92/0x1d0 [<ffffffff8157a191>] ? dev_queue_xmit+0xe1/0x830 [<ffffffff81726b7c>] _raw_spin_lock+0x3c/0x50 [<ffffffff8157a191>] ? dev_queue_xmit+0xe1/0x830 [<ffffffff8106264d>] ? rcu_read_lock_bh_held+0x5d/0x90 [<ffffffff8157a191>] dev_queue_xmit+0xe1/0x830 [<ffffffff8157a0b0>] ? netdev_pick_tx+0x570/0x570 [<ffffffffa0212a6a>] bond_start_xmit+0x1da/0x4b0 [bonding] [<ffffffff815796d0>] dev_hard_start_xmit+0x240/0x6b0 [<ffffffff81597c6e>] sch_direct_xmit+0xfe/0x2a0 [<ffffffff8157a249>] dev_queue_xmit+0x199/0x830 [<ffffffff8157a0b0>] ? netdev_pick_tx+0x570/0x570 [<ffffffff815ba96f>] ip_finish_output+0x5df/0x870 [<ffffffff815ba4bd>] ? ip_finish_output+0x12d/0x870 [<ffffffff815bb964>] ip_output+0x54/0xf0 [<ffffffff815bad48>] ip_local_out+0x28/0x90 [<ffffffff815bc444>] ip_send_skb+0x14/0x50 [<ffffffff815bc4b2>] ip_push_pending_frames+0x32/0x40 [<ffffffff815e536a>] raw_sendmsg+0x93a/0xc30 [<ffffffff8128d570>] ? selinux_file_send_sigiotask+0x1f0/0x1f0 [<ffffffff8109ddb4>] ? __lock_is_held+0x54/0x80 [<ffffffff815f6730>] ? inet_recvmsg+0x220/0x220 [<ffffffff8109ddb4>] ? __lock_is_held+0x54/0x80 [<ffffffff815f6855>] inet_sendmsg+0x125/0x240 [<ffffffff815f6730>] ? inet_recvmsg+0x220/0x220 [<ffffffff8155cddb>] sock_sendmsg+0xab/0xe0 [<ffffffff810a1650>] ? lock_release_non_nested+0xa0/0x2e0 [<ffffffff810a1650>] ? lock_release_non_nested+0xa0/0x2e0 [<ffffffff8155d18c>] __sys_sendmsg+0x37c/0x390 [<ffffffff81195b2a>] ? fsnotify+0x2ca/0x7e0 [<ffffffff811958e8>] ? fsnotify+0x88/0x7e0 [<ffffffff81361f36>] ? put_ldisc+0x56/0xd0 [<ffffffff8116f98a>] ? fget_light+0x3da/0x510 [<ffffffff8155f6c4>] sys_sendmsg+0x44/0x80 [<ffffffff8172fc22>] system_call_fastpath+0x16/0x1b Avoid this problem using a distinct lock_class_key for bonding devices. Signed-off-by: Eric Dumazet <[email protected]> Cc: Jay Vosburgh <[email protected]> Cc: Andy Gospodarek <[email protected]> Signed-off-by: David S. Miller <[email protected]>

In an effort to get fewer checkpatch reviewer corrections, add a networking specific style test for the preferred networking comment style. /* The preferred style for block comments in * drivers/net/... and net/... is like this */ These tests are only used in net/ and drivers/net/ Tested with: $ cat drivers/net/t.c /* foo */ /* * foo */ /* foo */ /* foo * bar */ $ ./scripts/checkpatch.pl -f drivers/net/t.c WARNING: networking block comments don't use an empty /* line, use /* Comment... #4: FILE: net/t.c:4: + +/* WARNING: networking block comments put the trailing */ on a separate line torvalds#12: FILE: net/t.c:12: + * bar */ total: 0 errors, 2 warnings, 12 lines checked Signed-off-by: Joe Perches <[email protected]> Cc: "Allan, Bruce W" <[email protected]> Cc: Andy Whitcroft <[email protected]> Cc: David Miller <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

We actually do not do anything about it. Just return a default value of zero and if the kernel tries to write anything but 0 we BUG_ON. This fixes the case when an user tries to suspend the machine and it blows up in save_processor_state b/c 'read_cr8' is set to NULL and we get: kernel BUG at /home/konrad/ssd/linux/arch/x86/include/asm/paravirt.h:100! invalid opcode: 0000 [#1] SMP Pid: 2687, comm: init.late Tainted: G O 3.6.0upstream-00002-gac264ac-dirty #4 Bochs Bochs RIP: e030:[<ffffffff814d5f42>] [<ffffffff814d5f42>] save_processor_state+0x212/0x270 .. snip.. Call Trace: [<ffffffff810733bf>] do_suspend_lowlevel+0xf/0xac [<ffffffff8107330c>] ? x86_acpi_suspend_lowlevel+0x10c/0x150 [<ffffffff81342ee2>] acpi_suspend_enter+0x57/0xd5 CC: [email protected] Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>

In 32 bit the stack address provided by kernel_stack_pointer() may point to an invalid range causing NULL pointer access or page faults while in NMI (see trace below). This happens if called in softirq context and if the stack is empty. The address at &regs->sp is then out of range. Fixing this by checking if regs and &regs->sp are in the same stack context. Otherwise return the previous stack pointer stored in struct thread_info. If that address is invalid too, return address of regs. BUG: unable to handle kernel NULL pointer dereference at 0000000a IP: [<c1004237>] print_context_stack+0x6e/0x8d *pde = 00000000 Oops: 0000 [#1] SMP Modules linked in: Pid: 4434, comm: perl Not tainted 3.6.0-rc3-oprofile-i386-standard-g4411a05 #4 Hewlett-Packard HP xw9400 Workstation/0A1Ch EIP: 0060:[<c1004237>] EFLAGS: 00010093 CPU: 0 EIP is at print_context_stack+0x6e/0x8d EAX: ffffe000 EBX: 0000000a ECX: f4435f94 EDX: 0000000a ESI: f4435f94 EDI: f4435f94 EBP: f5409ec0 ESP: f5409ea0 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 CR0: 8005003b CR2: 0000000a CR3: 34ac9000 CR4: 000007d0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff0ff0 DR7: 00000400 Process perl (pid: 4434, ti=f5408000 task=f5637850 task.ti=f4434000) Stack: 000003e8 ffffe000 00001ffc f4e39b00 00000000 0000000a f4435f94 c155198c f5409ef0 c1003723 c155198c f5409f04 00000000 f5409edc 00000000 00000000 f5409ee8 f4435f94 f5409fc4 00000001 f5409f1c c12dce1c 00000000 c155198c Call Trace: [<c1003723>] dump_trace+0x7b/0xa1 [<c12dce1c>] x86_backtrace+0x40/0x88 [<c12db712>] ? oprofile_add_sample+0x56/0x84 [<c12db731>] oprofile_add_sample+0x75/0x84 [<c12ddb5b>] op_amd_check_ctrs+0x46/0x260 [<c12dd40d>] profile_exceptions_notify+0x23/0x4c [<c1395034>] nmi_handle+0x31/0x4a [<c1029dc5>] ? ftrace_define_fields_irq_handler_entry+0x45/0x45 [<c13950ed>] do_nmi+0xa0/0x2ff [<c1029dc5>] ? ftrace_define_fields_irq_handler_entry+0x45/0x45 [<c13949e5>] nmi_stack_correct+0x28/0x2d [<c1029dc5>] ? ftrace_define_fields_irq_handler_entry+0x45/0x45 [<c1003603>] ? do_softirq+0x4b/0x7f <IRQ> [<c102a06f>] irq_exit+0x35/0x5b [<c1018f56>] smp_apic_timer_interrupt+0x6c/0x7a [<c1394746>] apic_timer_interrupt+0x2a/0x30 Code: 89 fe eb 08 31 c9 8b 45 0c ff 55 ec 83 c3 04 83 7d 10 00 74 0c 3b 5d 10 73 26 3b 5d e4 73 0c eb 1f 3b 5d f0 76 1a 3b 5d e8 73 15 <8b> 13 89 d0 89 55 e0 e8 ad 42 03 00 85 c0 8b 55 e0 75 a6 eb cc EIP: [<c1004237>] print_context_stack+0x6e/0x8d SS:ESP 0068:f5409ea0 CR2: 000000000000000a ---[ end trace 62afee3481b00012 ]--- Kernel panic - not syncing: Fatal exception in interrupt V2: * add comments to kernel_stack_pointer() * always return a valid stack address by falling back to the address of regs Reported-by: Yang Wei <[email protected]> Cc: <[email protected]> Signed-off-by: Robert Richter <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: H. Peter Anvin <[email protected]> Cc: Jun Zhang <[email protected]>

A rescue thread exiting TASK_INTERRUPTIBLE can lead to a task scheduling off, never to be seen again. In the case where this occurred, an exiting thread hit reiserfs homebrew conditional resched while holding a mutex, bringing the box to its knees. PID: 18105 TASK: ffff8807fd412180 CPU: 5 COMMAND: "kdmflush" #0 [ffff8808157e7670] schedule at ffffffff8143f489 #1 [ffff8808157e77b8] reiserfs_get_block at ffffffffa038ab2d [reiserfs] #2 [ffff8808157e79a8] __block_write_begin at ffffffff8117fb14 #3 [ffff8808157e7a98] reiserfs_write_begin at ffffffffa0388695 [reiserfs] #4 [ffff8808157e7ad8] generic_perform_write at ffffffff810ee9e2 #5 [ffff8808157e7b58] generic_file_buffered_write at ffffffff810eeb41 torvalds#6 [ffff8808157e7ba8] __generic_file_aio_write at ffffffff810f1a3a torvalds#7 [ffff8808157e7c58] generic_file_aio_write at ffffffff810f1c88 torvalds#8 [ffff8808157e7cc8] do_sync_write at ffffffff8114f850 torvalds#9 [ffff8808157e7dd8] do_acct_process at ffffffff810a268f [exception RIP: kernel_thread_helper] RIP: ffffffff8144a5c0 RSP: ffff8808157e7f58 RFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8107af60 RDI: ffff8803ee491d18 RBP: 0000000000000000 R8: 0000000000000000 R9: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 Signed-off-by: Mike Galbraith <[email protected]> Signed-off-by: Tejun Heo <[email protected]> Cc: [email protected]

As pointed out by Geert, MC68000 target needs to be disabled when MMU support is enabled. From Geert: This needs a "depends on !MMU". Else allmodconfig will select it, causing -m68000 to be passed to the assembler, which may break the build depending on your version of binutils, a.o. arch/m68k/kernel/entry.S:186: Error: invalid instruction for this architecture; needs 68020 or higher (68020 [68k, 68ec020], 68030 [68ec030], 68040 [68ec040], 68060 [68ec060]) -- statement `bfextu %sp@(50){#0,#4},%d0' ignored arch/m68k/kernel/entry.S:211: Error: invalid operand mode for this architecture; needs 68020 or higher -- statement `jbsr @(sys_call_table,%d0:l:4)@(0)' ignored Cfr. http://kisskb.ellerman.id.au/kisskb/buildresult/7416877/ Signed-off-by: Luis Alves <[email protected]> Signed-off-by: Greg Ungerer <[email protected]>

The offset must be multiplied by 4 to be sure to access the correct 32bit word in the stack scratch space. For instance, a store at scratch memory cell #1 was generating the following: st r4, [sp, #1] While the correct code for this is: st r4, [sp, #4] To reproduce the bug (assuming your system has a NIC with the mac address 52:54:00:12:34:56): echo 0 > /proc/sys/net/core/bpf_jit_enable tcpdump -ni eth0 "ether[1] + ether[2] - ether[3] * ether[4] - ether[5] \ == -0x3AA" # this will capture packets as expected echo 1 > /proc/sys/net/core/bpf_jit_enable tcpdump -ni eth0 "ether[1] + ether[2] - ether[3] * ether[4] - ether[5] \ == -0x3AA" # this will not. This bug was present since the original inclusion of bpf_jit for ARM (ddecdfc: ARM: 7259/3: net: JIT compiler for packet filters). Signed-off-by: Nicolas Schichan <[email protected]> Signed-off-by: Russell King <[email protected]>

Commit 648bb56 ("cgroup: lock cgroup_mutex in cgroup_init_subsys()") made cgroup_init_subsys() grab cgroup_mutex before invoking ->css_alloc() for the root css. Because memcg registers hotcpu notifier from ->css_alloc() for the root css, this introduced circular locking dependency between cgroup_mutex and cpu hotplug. Fix it by moving hotcpu notifier registration to a subsys initcall. ====================================================== [ INFO: possible circular locking dependency detected ] 3.7.0-rc4-work+ torvalds#42 Not tainted ------------------------------------------------------- bash/645 is trying to acquire lock: (cgroup_mutex){+.+.+.}, at: [<ffffffff8110c5b7>] cgroup_lock+0x17/0x20 but task is already holding lock: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109300f>] cpu_hotplug_begin+0x2f/0x60 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (cpu_hotplug.lock){+.+.+.}: lock_acquire+0x97/0x1e0 mutex_lock_nested+0x61/0x3b0 get_online_cpus+0x3c/0x60 rebuild_sched_domains_locked+0x1b/0x70 cpuset_write_resmask+0x298/0x2c0 cgroup_file_write+0x1ef/0x300 vfs_write+0xa8/0x160 sys_write+0x52/0xa0 system_call_fastpath+0x16/0x1b -> #0 (cgroup_mutex){+.+.+.}: __lock_acquire+0x14ce/0x1d20 lock_acquire+0x97/0x1e0 mutex_lock_nested+0x61/0x3b0 cgroup_lock+0x17/0x20 cpuset_handle_hotplug+0x1b/0x560 cpuset_update_active_cpus+0xe/0x10 cpuset_cpu_inactive+0x47/0x50 notifier_call_chain+0x66/0x150 __raw_notifier_call_chain+0xe/0x10 __cpu_notify+0x20/0x40 _cpu_down+0x7e/0x2f0 cpu_down+0x36/0x50 store_online+0x5d/0xe0 dev_attr_store+0x18/0x30 sysfs_write_file+0xe0/0x150 vfs_write+0xa8/0x160 sys_write+0x52/0xa0 system_call_fastpath+0x16/0x1b other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(cpu_hotplug.lock); lock(cgroup_mutex); lock(cpu_hotplug.lock); lock(cgroup_mutex); *** DEADLOCK *** 5 locks held by bash/645: #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff8123bab8>] sysfs_write_file+0x48/0x150 #1: (s_active#42){.+.+.+}, at: [<ffffffff8123bb38>] sysfs_write_file+0xc8/0x150 #2: (x86_cpu_hotplug_driver_mutex){+.+...}, at: [<ffffffff81079277>] cpu_hotplug_driver_lock+0x1 +7/0x20 #3: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff81093157>] cpu_maps_update_begin+0x17/0x20 #4: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109300f>] cpu_hotplug_begin+0x2f/0x60 stack backtrace: Pid: 645, comm: bash Not tainted 3.7.0-rc4-work+ torvalds#42 Call Trace: print_circular_bug+0x28e/0x29f __lock_acquire+0x14ce/0x1d20 lock_acquire+0x97/0x1e0 mutex_lock_nested+0x61/0x3b0 cgroup_lock+0x17/0x20 cpuset_handle_hotplug+0x1b/0x560 cpuset_update_active_cpus+0xe/0x10 cpuset_cpu_inactive+0x47/0x50 notifier_call_chain+0x66/0x150 __raw_notifier_call_chain+0xe/0x10 __cpu_notify+0x20/0x40 _cpu_down+0x7e/0x2f0 cpu_down+0x36/0x50 store_online+0x5d/0xe0 dev_attr_store+0x18/0x30 sysfs_write_file+0xe0/0x150 vfs_write+0xa8/0x160 sys_write+0x52/0xa0 system_call_fastpath+0x16/0x1b Signed-off-by: Tejun Heo <[email protected]> Reported-by: Fengguang Wu <[email protected]> Acked-by: Michal Hocko <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

The new_node_page() is processed as the following procedure. 1. A new node page is allocated. 2. Set PageUptodate with proper footer information. 3. Check if there is a free space for allocation 4.a. If there is no space, f2fs returns with -ENOSPC. 4.b. Otherwise, go next. In the case of step #4.a, f2fs remains a wrong node page in the page cache with the uptodate flag. Also, even though a new node page is allocated successfully, an error can be occurred afterwards due to allocation failure of the other data structures. In such a case, remove_inode_page() would be triggered, so that we have to clear uptodate flag in truncate_node() too. So, we should remove the uptodate flag, if allocation is failed. Signed-off-by: Jaegeuk Kim <[email protected]>

Pursuant to this review https://lkml.org/lkml/2012/11/12/500 by Stefan Richter, update the TODO file. - Clarify purpose of TODO file - Remove firewire item #4. As discussed in this conversation https://lkml.org/lkml/2012/11/13/564 knowing the AR buffer size is not a hard requirement. The required rx buffer size can be determined experimentally. - Remove firewire item #5. This was a private note for further experimentation. - Change firewire item #1. Change suggested header from uapi header to kernel-only header. Signed-off-by: Peter Hurley <[email protected]> Acked-by: Stefan Richter <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

-Top level ARC makefile removes -I for platform headers -asm/irq.h no longer includes plat/irq.h -platform makefile adds -I for it's specfic platform headers -platform code to directly include it's plat/irq.h -Linker script needed plat/memmap.h for CCM info, already in .config Signed-off-by: Vineet Gupta <[email protected]> Cc: Arnd Bergmann <[email protected]> Acked-by: Arnd Bergmann <[email protected]>

This fixes an oops where a LAYOUTGET is in still in the rpciod queue, but the requesting processes has been killed. Without this, killing the process does the final pnfs_put_layout_hdr() and sets NFS_I(inode)->layout to NULL while the LAYOUTGET rpc task still references it. Example oops: BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: [<ffffffffa01bd586>] pnfs_choose_layoutget_stateid+0x37/0xef [nfsv4] PGD 7365b067 PUD 7365d067 PMD 0 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: nfs_layout_nfsv41_files nfsv4 auth_rpcgss nfs lockd sunrpc ipt_MASQUERADE ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle ip6table_filter ip6_tables ppdev e1000 i2c_piix4 i2c_core shpchp parport_pc parport crc32c_intel aesni_intel xts aes_x86_64 lrw gf128mul ablk_helper cryptd mptspi scsi_transport_spi mptscsih mptbase floppy autofs4 CPU 0 Pid: 27, comm: kworker/0:1 Not tainted 3.8.0-dros_cthon2013+ #4 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform RIP: 0010:[<ffffffffa01bd586>] [<ffffffffa01bd586>] pnfs_choose_layoutget_stateid+0x37/0xef [nfsv4] RSP: 0018:ffff88007b0c1c88 EFLAGS: 00010246 RAX: ffff88006ed36678 RBX: 0000000000000000 RCX: 0000000ea877e3bc RDX: ffff88007a729da8 RSI: 0000000000000000 RDI: ffff88007a72b958 RBP: ffff88007b0c1ca8 R08: 0000000000000002 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88007a72b958 R13: ffff88007a729da8 R14: 0000000000000000 R15: ffffffffa011077e FS: 0000000000000000(0000) GS:ffff88007f600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000000735f8000 CR4: 00000000001407f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process kworker/0:1 (pid: 27, threadinfo ffff88007b0c0000, task ffff88007c2fa0c0) Stack: ffff88006fc05388 ffff88007a72b908 ffff88007b240900 ffff88006fc05388 ffff88007b0c1cd8 ffffffffa01a2170 ffff88007b240900 ffff88007b240900 ffff88007b240970 ffffffffa011077e ffff88007b0c1ce8 ffffffffa0110791 Call Trace: [<ffffffffa01a2170>] nfs4_layoutget_prepare+0x7b/0x92 [nfsv4] [<ffffffffa011077e>] ? __rpc_atrun+0x15/0x15 [sunrpc] [<ffffffffa0110791>] rpc_prepare_task+0x13/0x15 [sunrpc] Reported-by: Tigran Mkrtchyan <[email protected]> Signed-off-by: Weston Andros Adamson <[email protected]> Cc: [email protected] Signed-off-by: Trond Myklebust <[email protected]>

…ernel/git/vgupta/arc Pull new ARC architecture from Vineet Gupta: "Initial ARC Linux port with some fixes on top for 3.9-rc1: I would like to introduce the Linux port to ARC Processors (from Synopsys) for 3.9-rc1. The patch-set has been discussed on the public lists since Nov and has received a fair bit of review, specially from Arnd, tglx, Al and other subsystem maintainers for DeviceTree, kgdb... The arch bits are in arch/arc, some asm-generic changes (acked by Arnd), a minor change to PARISC (acked by Helge). The series is a touch bigger for a new port for 2 main reasons: 1. It enables a basic kernel in first sub-series and adds ptrace/kgdb/.. later 2. Some of the fallout of review (DeviceTree support, multi-platform- image support) were added on top of orig series, primarily to record the revision history. This updated pull request additionally contains - fixes due to our GNU tools catching up with the new syscall/ptrace ABI - some (minor) cross-arch Kconfig updates." * tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (82 commits) ARC: split elf.h into uapi and export it for userspace ARC: Fixup the current ABI version ARC: gdbserver using regset interface possibly broken ARC: Kconfig cleanup tracking cross-arch Kconfig pruning in merge window ARC: make a copy of flat DT ARC: [plat-arcfpga] DT arc-uart bindings change: "baud" => "current-speed" ARC: Ensure CONFIG_VIRT_TO_BUS is not enabled ARC: Fix pt_orig_r8 access ARC: [3.9] Fallout of hlist iterator update ARC: 64bit RTSC timestamp hardware issue ARC: Don't fiddle with non-existent caches ARC: Add self to MAINTAINERS ARC: Provide a default serial.h for uart drivers needing BASE_BAUD ARC: [plat-arcfpga] defconfig for fully loaded ARC Linux ARC: [Review] Multi-platform image torvalds#8: platform registers SMP callbacks ARC: [Review] Multi-platform image torvalds#7: SMP common code to use callbacks ARC: [Review] Multi-platform image torvalds#6: cpu-to-dma-addr optional ARC: [Review] Multi-platform image #5: NR_IRQS defined by ARC core ARC: [Review] Multi-platform image #4: Isolate platform headers ARC: [Review] Multi-platform image #3: switch to board callback ...

…optimizations Recent GCC versions (e.g. GCC-4.7.2) perform optimizations based on assumptions about the implementation of memset and similar functions. The current ARM optimized memset code does not return the value of its first argument, as is usually expected from standard implementations. For instance in the following function: void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter) { memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter)); waiter->magic = waiter; INIT_LIST_HEAD(&waiter->list); } compiled as: 800554d0 <debug_mutex_lock_common>: 800554d0: e92d4008 push {r3, lr} 800554d4: e1a00001 mov r0, r1 800554d8: e3a02010 mov r2, torvalds#16 ; 0x10 800554dc: e3a01011 mov r1, torvalds#17 ; 0x11 800554e0: eb04426e bl 80165ea0 <memset> 800554e4: e1a03000 mov r3, r0 800554e8: e583000c str r0, [r3, torvalds#12] 800554ec: e5830000 str r0, [r3] 800554f0: e5830004 str r0, [r3, #4] 800554f4: e8bd8008 pop {r3, pc} GCC assumes memset returns the value of pointer 'waiter' in register r0; causing register/memory corruptions. This patch fixes the return value of the assembly version of memset. It adds a 'mov' instruction and merges an additional load+store into existing load/store instructions. For ease of review, here is a breakdown of the patch into 4 simple steps: Step 1 ====== Perform the following substitutions: ip -> r8, then r0 -> ip, and insert 'mov ip, r0' as the first statement of the function. At this point, we have a memset() implementation returning the proper result, but corrupting r8 on some paths (the ones that were using ip). Step 2 ====== Make sure r8 is saved and restored when (! CALGN(1)+0) == 1: save r8: - str lr, [sp, #-4]! + stmfd sp!, {r8, lr} and restore r8 on both exit paths: - ldmeqfd sp!, {pc} @ Now <64 bytes to go. + ldmeqfd sp!, {r8, pc} @ Now <64 bytes to go. (...) tst r2, torvalds#16 stmneia ip!, {r1, r3, r8, lr} - ldr lr, [sp], #4 + ldmfd sp!, {r8, lr} Step 3 ====== Make sure r8 is saved and restored when (! CALGN(1)+0) == 0: save r8: - stmfd sp!, {r4-r7, lr} + stmfd sp!, {r4-r8, lr} and restore r8 on both exit paths: bgt 3b - ldmeqfd sp!, {r4-r7, pc} + ldmeqfd sp!, {r4-r8, pc} (...) tst r2, torvalds#16 stmneia ip!, {r4-r7} - ldmfd sp!, {r4-r7, lr} + ldmfd sp!, {r4-r8, lr} Step 4 ====== Rewrite register list "r4-r7, r8" as "r4-r8". Signed-off-by: Ivan Djelic <[email protected]> Reviewed-by: Nicolas Pitre <[email protected]> Signed-off-by: Dirk Behme <[email protected]> Signed-off-by: Russell King <[email protected]>

The following script will produce a kernel oops: sudo ip netns add v sudo ip netns exec v ip ad add 127.0.0.1/8 dev lo sudo ip netns exec v ip link set lo up sudo ip netns exec v ip ro add 224.0.0.0/4 dev lo sudo ip netns exec v ip li add vxlan0 type vxlan id 42 group 239.1.1.1 dev lo sudo ip netns exec v ip link set vxlan0 up sudo ip netns del v where inspect by gdb: Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 107] 0xffffffffa0289e33 in ?? () (gdb) bt #0 vxlan_leave_group (dev=0xffff88001bafa000) at drivers/net/vxlan.c:533 #1 vxlan_stop (dev=0xffff88001bafa000) at drivers/net/vxlan.c:1087 #2 0xffffffff812cc498 in __dev_close_many (head=head@entry=0xffff88001f2e7dc8) at net/core/dev.c:1299 #3 0xffffffff812cd920 in dev_close_many (head=head@entry=0xffff88001f2e7dc8) at net/core/dev.c:1335 #4 0xffffffff812cef31 in rollback_registered_many (head=head@entry=0xffff88001f2e7dc8) at net/core/dev.c:4851 #5 0xffffffff812cf040 in unregister_netdevice_many (head=head@entry=0xffff88001f2e7dc8) at net/core/dev.c:5752 torvalds#6 0xffffffff812cf1ba in default_device_exit_batch (net_list=0xffff88001f2e7e18) at net/core/dev.c:6170 torvalds#7 0xffffffff812cab27 in cleanup_net (work=<optimized out>) at net/core/net_namespace.c:302 torvalds#8 0xffffffff810540ef in process_one_work (worker=0xffff88001ba9ed40, work=0xffffffff8167d020) at kernel/workqueue.c:2157 torvalds#9 0xffffffff810549d0 in worker_thread (__worker=__worker@entry=0xffff88001ba9ed40) at kernel/workqueue.c:2276 torvalds#10 0xffffffff8105870c in kthread (_create=0xffff88001f2e5d68) at kernel/kthread.c:168 torvalds#11 <signal handler called> torvalds#12 0x0000000000000000 in ?? () torvalds#13 0x0000000000000000 in ?? () (gdb) fr 0 #0 vxlan_leave_group (dev=0xffff88001bafa000) at drivers/net/vxlan.c:533 533 struct sock *sk = vn->sock->sk; (gdb) l 528 static int vxlan_leave_group(struct net_device *dev) 529 { 530 struct vxlan_dev *vxlan = netdev_priv(dev); 531 struct vxlan_net *vn = net_generic(dev_net(dev), vxlan_net_id); 532 int err = 0; 533 struct sock *sk = vn->sock->sk; 534 struct ip_mreqn mreq = { 535 .imr_multiaddr.s_addr = vxlan->gaddr, 536 .imr_ifindex = vxlan->link, 537 }; (gdb) p vn->sock $4 = (struct socket *) 0x0 The kernel calls `vxlan_exit_net` when deleting the netns before shutting down vxlan interfaces. Later the removal of all vxlan interfaces, where `vn->sock` is already gone causes the oops. so we should manually shutdown all interfaces before deleting `vn->sock` as the patch does. Signed-off-by: Zang MingJie <[email protected]> Signed-off-by: David S. Miller <[email protected]>

snd_seq_timer_open() didn't catch the whole error path but let through if the timer id is a slave. This may lead to Oops by accessing the uninitialized pointer. BUG: unable to handle kernel NULL pointer dereference at 00000000000002ae IP: [<ffffffff819b3477>] snd_seq_timer_open+0xe7/0x130 PGD 785cd067 PUD 76964067 PMD 0 Oops: 0002 [#4] SMP CPU 0 Pid: 4288, comm: trinity-child7 Tainted: G D W 3.9.0-rc1+ torvalds#100 Bochs Bochs RIP: 0010:[<ffffffff819b3477>] [<ffffffff819b3477>] snd_seq_timer_open+0xe7/0x130 RSP: 0018:ffff88006ece7d38 EFLAGS: 00010246 RAX: 0000000000000286 RBX: ffff88007851b400 RCX: 0000000000000000 RDX: 000000000000ffff RSI: ffff88006ece7d58 RDI: ffff88006ece7d38 RBP: ffff88006ece7d98 R08: 000000000000000a R09: 000000000000fffe R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8800792c5400 R14: 0000000000e8f000 R15: 0000000000000007 FS: 00007f7aaa650700(0000) GS:ffff88007f800000(0000) GS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000002ae CR3: 000000006efec000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process trinity-child7 (pid: 4288, threadinfo ffff88006ece6000, task ffff880076a8a290) Stack: 0000000000000286 ffffffff828f2be0 ffff88006ece7d58 ffffffff810f354d 65636e6575716573 2065756575712072 ffff8800792c0030 0000000000000000 ffff88006ece7d98 ffff8800792c5400 ffff88007851b400 ffff8800792c5520 Call Trace: [<ffffffff810f354d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff819b17e9>] snd_seq_queue_timer_open+0x29/0x70 [<ffffffff819ae01a>] snd_seq_ioctl_set_queue_timer+0xda/0x120 [<ffffffff819acb9b>] snd_seq_do_ioctl+0x9b/0xd0 [<ffffffff819acbe0>] snd_seq_ioctl+0x10/0x20 [<ffffffff811b9542>] do_vfs_ioctl+0x522/0x570 [<ffffffff8130a4b3>] ? file_has_perm+0x83/0xa0 [<ffffffff810f354d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff811b95ed>] sys_ioctl+0x5d/0xa0 [<ffffffff813663fe>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff81faed69>] system_call_fastpath+0x16/0x1b Reported-and-tested-by: Tommi Rantala <[email protected]> Cc: <[email protected]> Signed-off-by: Takashi Iwai <[email protected]>

ca22e56 (driver-core: implement 'sysdev' functionality for regular devices and buses) has introduced bus_register macro with a static key to distinguish different subsys mutex classes. This however doesn't work for different subsys which use a common registering function. One example is subsys_system_register (and mce_device and cpu_device). In the end this leads to the following lockdep splat: [ 207.271924] ====================================================== [ 207.271932] [ INFO: possible circular locking dependency detected ] [ 207.271942] 3.9.0-rc1-0.7-default+ torvalds#34 Not tainted [ 207.271948] ------------------------------------------------------- [ 207.271957] bash/10493 is trying to acquire lock: [ 207.271963] (subsys mutex){+.+.+.}, at: [<ffffffff8134af27>] bus_remove_device+0x37/0x1c0 [ 207.271987] [ 207.271987] but task is already holding lock: [ 207.271995] (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff81046ccf>] cpu_hotplug_begin+0x2f/0x60 [ 207.272012] [ 207.272012] which lock already depends on the new lock. [ 207.272012] [ 207.272023] [ 207.272023] the existing dependency chain (in reverse order) is: [ 207.272033] [ 207.272033] -> #4 (cpu_hotplug.lock){+.+.+.}: [ 207.272044] [<ffffffff810ae329>] lock_acquire+0xe9/0x120 [ 207.272056] [<ffffffff814ad807>] mutex_lock_nested+0x37/0x360 [ 207.272069] [<ffffffff81046ba9>] get_online_cpus+0x29/0x40 [ 207.272082] [<ffffffff81185210>] drain_all_stock+0x30/0x150 [ 207.272094] [<ffffffff811853da>] mem_cgroup_reclaim+0xaa/0xe0 [ 207.272104] [<ffffffff8118775e>] __mem_cgroup_try_charge+0x51e/0xcf0 [ 207.272114] [<ffffffff81188486>] mem_cgroup_charge_common+0x36/0x60 [ 207.272125] [<ffffffff811884da>] mem_cgroup_newpage_charge+0x2a/0x30 [ 207.272135] [<ffffffff81150531>] do_wp_page+0x231/0x830 [ 207.272147] [<ffffffff8115151e>] handle_pte_fault+0x19e/0x8d0 [ 207.272157] [<ffffffff81151da8>] handle_mm_fault+0x158/0x1e0 [ 207.272166] [<ffffffff814b6153>] do_page_fault+0x2a3/0x4e0 [ 207.272178] [<ffffffff814b2578>] page_fault+0x28/0x30 [ 207.272189] [ 207.272189] -> #3 (&mm->mmap_sem){++++++}: [ 207.272199] [<ffffffff810ae329>] lock_acquire+0xe9/0x120 [ 207.272208] [<ffffffff8114c5ad>] might_fault+0x6d/0x90 [ 207.272218] [<ffffffff811a11e3>] filldir64+0xb3/0x120 [ 207.272229] [<ffffffffa013fc19>] call_filldir+0x89/0x130 [ext3] [ 207.272248] [<ffffffffa0140377>] ext3_readdir+0x6b7/0x7e0 [ext3] [ 207.272263] [<ffffffff811a1519>] vfs_readdir+0xa9/0xc0 [ 207.272273] [<ffffffff811a15cb>] sys_getdents64+0x9b/0x110 [ 207.272284] [<ffffffff814bb599>] system_call_fastpath+0x16/0x1b [ 207.272296] [ 207.272296] -> #2 (&type->i_mutex_dir_key#3){+.+.+.}: [ 207.272309] [<ffffffff810ae329>] lock_acquire+0xe9/0x120 [ 207.272319] [<ffffffff814ad807>] mutex_lock_nested+0x37/0x360 [ 207.272329] [<ffffffff8119c254>] link_path_walk+0x6f4/0x9a0 [ 207.272339] [<ffffffff8119e7fa>] path_openat+0xba/0x470 [ 207.272349] [<ffffffff8119ecf8>] do_filp_open+0x48/0xa0 [ 207.272358] [<ffffffff8118d81c>] file_open_name+0xdc/0x110 [ 207.272369] [<ffffffff8118d885>] filp_open+0x35/0x40 [ 207.272378] [<ffffffff8135c76e>] _request_firmware+0x52e/0xb20 [ 207.272389] [<ffffffff8135cdd6>] request_firmware+0x16/0x20 [ 207.272399] [<ffffffffa03bdb91>] request_microcode_fw+0x61/0xd0 [microcode] [ 207.272416] [<ffffffffa03bd554>] microcode_init_cpu+0x104/0x150 [microcode] [ 207.272431] [<ffffffffa03bd61c>] mc_device_add+0x7c/0xb0 [microcode] [ 207.272444] [<ffffffff8134a419>] subsys_interface_register+0xc9/0x100 [ 207.272457] [<ffffffffa04fc0f4>] 0xffffffffa04fc0f4 [ 207.272472] [<ffffffff81000202>] do_one_initcall+0x42/0x180 [ 207.272485] [<ffffffff810bbeff>] load_module+0x19df/0x1b70 [ 207.272499] [<ffffffff810bc376>] sys_init_module+0xe6/0x130 [ 207.272511] [<ffffffff814bb599>] system_call_fastpath+0x16/0x1b [ 207.272523] [ 207.272523] -> #1 (umhelper_sem){++++.+}: [ 207.272537] [<ffffffff810ae329>] lock_acquire+0xe9/0x120 [ 207.272548] [<ffffffff814ae9c4>] down_read+0x34/0x50 [ 207.272559] [<ffffffff81062bff>] usermodehelper_read_trylock+0x4f/0x100 [ 207.272575] [<ffffffff8135c7dd>] _request_firmware+0x59d/0xb20 [ 207.272587] [<ffffffff8135cdd6>] request_firmware+0x16/0x20 [ 207.272599] [<ffffffffa03bdb91>] request_microcode_fw+0x61/0xd0 [microcode] [ 207.272613] [<ffffffffa03bd554>] microcode_init_cpu+0x104/0x150 [microcode] [ 207.272627] [<ffffffffa03bd61c>] mc_device_add+0x7c/0xb0 [microcode] [ 207.272641] [<ffffffff8134a419>] subsys_interface_register+0xc9/0x100 [ 207.272654] [<ffffffffa04fc0f4>] 0xffffffffa04fc0f4 [ 207.272666] [<ffffffff81000202>] do_one_initcall+0x42/0x180 [ 207.272678] [<ffffffff810bbeff>] load_module+0x19df/0x1b70 [ 207.272690] [<ffffffff810bc376>] sys_init_module+0xe6/0x130 [ 207.272702] [<ffffffff814bb599>] system_call_fastpath+0x16/0x1b [ 207.272715] [ 207.272715] -> #0 (subsys mutex){+.+.+.}: [ 207.272729] [<ffffffff810ae002>] __lock_acquire+0x13b2/0x15f0 [ 207.272740] [<ffffffff810ae329>] lock_acquire+0xe9/0x120 [ 207.272751] [<ffffffff814ad807>] mutex_lock_nested+0x37/0x360 [ 207.272763] [<ffffffff8134af27>] bus_remove_device+0x37/0x1c0 [ 207.272775] [<ffffffff81349114>] device_del+0x134/0x1f0 [ 207.272786] [<ffffffff813491f2>] device_unregister+0x22/0x60 [ 207.272798] [<ffffffff814a24ea>] mce_cpu_callback+0x15e/0x1ad [ 207.272812] [<ffffffff814b6402>] notifier_call_chain+0x72/0x130 [ 207.272824] [<ffffffff81073d6e>] __raw_notifier_call_chain+0xe/0x10 [ 207.272839] [<ffffffff81498f76>] _cpu_down+0x1d6/0x350 [ 207.272851] [<ffffffff81499130>] cpu_down+0x40/0x60 [ 207.272862] [<ffffffff8149cc55>] store_online+0x75/0xe0 [ 207.272874] [<ffffffff813474a0>] dev_attr_store+0x20/0x30 [ 207.272886] [<ffffffff812090d9>] sysfs_write_file+0xd9/0x150 [ 207.272900] [<ffffffff8118e10b>] vfs_write+0xcb/0x130 [ 207.272911] [<ffffffff8118e924>] sys_write+0x64/0xa0 [ 207.272923] [<ffffffff814bb599>] system_call_fastpath+0x16/0x1b [ 207.272936] [ 207.272936] other info that might help us debug this: [ 207.272936] [ 207.272952] Chain exists of: [ 207.272952] subsys mutex --> &mm->mmap_sem --> cpu_hotplug.lock [ 207.272952] [ 207.272973] Possible unsafe locking scenario: [ 207.272973] [ 207.272984] CPU0 CPU1 [ 207.272992] ---- ---- [ 207.273000] lock(cpu_hotplug.lock); [ 207.273009] lock(&mm->mmap_sem); [ 207.273020] lock(cpu_hotplug.lock); [ 207.273031] lock(subsys mutex); [ 207.273040] [ 207.273040] *** DEADLOCK *** [ 207.273040] [ 207.273055] 5 locks held by bash/10493: [ 207.273062] #0: (&buffer->mutex){+.+.+.}, at: [<ffffffff81209049>] sysfs_write_file+0x49/0x150 [ 207.273080] #1: (s_active#150){.+.+.+}, at: [<ffffffff812090c2>] sysfs_write_file+0xc2/0x150 [ 207.273099] #2: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff81027557>] cpu_hotplug_driver_lock+0x17/0x20 [ 207.273121] #3: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff8149911c>] cpu_down+0x2c/0x60 [ 207.273140] #4: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff81046ccf>] cpu_hotplug_begin+0x2f/0x60 [ 207.273158] [ 207.273158] stack backtrace: [ 207.273170] Pid: 10493, comm: bash Not tainted 3.9.0-rc1-0.7-default+ torvalds#34 [ 207.273180] Call Trace: [ 207.273192] [<ffffffff810ab373>] print_circular_bug+0x223/0x310 [ 207.273204] [<ffffffff810ae002>] __lock_acquire+0x13b2/0x15f0 [ 207.273216] [<ffffffff812086b0>] ? sysfs_hash_and_remove+0x60/0xc0 [ 207.273227] [<ffffffff810ae329>] lock_acquire+0xe9/0x120 [ 207.273239] [<ffffffff8134af27>] ? bus_remove_device+0x37/0x1c0 [ 207.273251] [<ffffffff814ad807>] mutex_lock_nested+0x37/0x360 [ 207.273263] [<ffffffff8134af27>] ? bus_remove_device+0x37/0x1c0 [ 207.273274] [<ffffffff812086b0>] ? sysfs_hash_and_remove+0x60/0xc0 [ 207.273286] [<ffffffff8134af27>] bus_remove_device+0x37/0x1c0 [ 207.273298] [<ffffffff81349114>] device_del+0x134/0x1f0 [ 207.273309] [<ffffffff813491f2>] device_unregister+0x22/0x60 [ 207.273321] [<ffffffff814a24ea>] mce_cpu_callback+0x15e/0x1ad [ 207.273332] [<ffffffff814b6402>] notifier_call_chain+0x72/0x130 [ 207.273344] [<ffffffff81073d6e>] __raw_notifier_call_chain+0xe/0x10 [ 207.273356] [<ffffffff81498f76>] _cpu_down+0x1d6/0x350 [ 207.273368] [<ffffffff81027557>] ? cpu_hotplug_driver_lock+0x17/0x20 [ 207.273380] [<ffffffff81499130>] cpu_down+0x40/0x60 [ 207.273391] [<ffffffff8149cc55>] store_online+0x75/0xe0 [ 207.273402] [<ffffffff813474a0>] dev_attr_store+0x20/0x30 [ 207.273413] [<ffffffff812090d9>] sysfs_write_file+0xd9/0x150 [ 207.273425] [<ffffffff8118e10b>] vfs_write+0xcb/0x130 [ 207.273436] [<ffffffff8118e924>] sys_write+0x64/0xa0 [ 207.273447] [<ffffffff814bb599>] system_call_fastpath+0x16/0x1b Which reports a false possitive deadlock because it sees: 1) load_module -> subsys_interface_register -> mc_deveice_add (*) -> subsys->p->mutex -> link_path_walk -> lookup_slow -> i_mutex 2) sys_write -> _cpu_down -> cpu_hotplug_begin -> cpu_hotplug.lock -> mce_cpu_callback -> mce_device_remove(**) -> device_unregister -> bus_remove_device -> subsys mutex 3) vfs_readdir -> i_mutex -> filldir64 -> might_fault -> might_lock_read(mmap_sem) -> page_fault -> mmap_sem -> drain_all_stock -> cpu_hotplug.lock but 1) takes cpu_subsys subsys (*) but 2) takes mce_device subsys (**) so the deadlock is not possible AFAICS. The fix is quite simple. We can pull the key inside bus_type structure because they are defined per device so the pointer will be unique as well. bus_register doesn't need to be a macro anymore so change it to the inline. We could get rid of __bus_register as there is no other caller but maybe somebody will want to use a different key so keep it around for now. Reported-by: Li Zefan <[email protected]> Signed-off-by: Michal Hocko <[email protected]> Signed-off-by: Jiri Kosina <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

The first backtrace appears on tx path with DMA mapping operations debug enabled. [ 345.637919] ------------[ cut here ]------------ [ 345.637971] WARNING: at lib/dma-debug.c:937 check_unmap+0x4df/0x910() [ 345.637977] Hardware name: System Name [ 345.637987] sis900 0000:00:01.1: DMA-API: device driver failed to check map error[device address=0x000000000d4aed02] [si ze=60 bytes] [mapped as single] [ 345.637993] Modules linked in: bridge stp llc dmfe sundance 3c59x sis900 [ 345.638022] Pid: 0, comm: swapper Not tainted 3.9.0-rc6+ #4 [ 345.638028] Call Trace: [ 345.638042] [<c122097f>] ? check_unmap+0x4df/0x910 [ 345.638059] [<c102b19c>] warn_slowpath_common+0x7c/0xa0 [ 345.638070] [<c122097f>] ? check_unmap+0x4df/0x910 [ 345.638081] [<c102b23e>] warn_slowpath_fmt+0x2e/0x30 [ 345.638092] [<c122097f>] check_unmap+0x4df/0x910 [ 345.638107] [<c100bfeb>] ? save_stack_trace+0x2b/0x50 [ 345.638120] [<c107238e>] ? mark_lock+0x31e/0x5d0 [ 345.638132] [<c1072b2c>] ? __lock_acquire+0x4ec/0x7d0 [ 345.638143] [<c1220f6d>] debug_dma_unmap_page+0x6d/0x80 [ 345.638166] [<cf834dec>] sis900_interrupt+0x49c/0x860 [sis900] [ 345.638195] [<c1094b73>] handle_irq_event_percpu+0x43/0x1c0 [ 345.638206] [<c1094d1e>] ? handle_irq_event+0x2e/0x60 [ 345.638217] [<c1094d27>] handle_irq_event+0x37/0x60 [ 345.638235] [<c10973f0>] ? irq_set_chip_data+0x40/0x40 [ 345.638246] [<c1097442>] handle_level_irq+0x52/0xa0 [ 345.638251] <IRQ> [<c1003629>] ? do_IRQ+0x39/0xa0 [ 345.638293] [<c1484631>] ? common_interrupt+0x31/0x36 [ 345.638347] [<d08c2c52>] ? br_flood_forward+0x12/0x20 [bridge] [ 345.638364] [<d08c2d40>] ? br_dev_queue_push_xmit+0x60/0x60 [bridge] [ 345.638381] [<d08c3b2b>] ? br_handle_frame_finish+0x25b/0x280 [bridge] [ 345.638399] [<d08c3ce3>] ? br_handle_frame+0x193/0x290 [bridge] [ 345.638416] [<d08c3b50>] ? br_handle_frame_finish+0x280/0x280 [bridge] [ 345.638431] [<c13b3c87>] ? __netif_receive_skb_core+0x1d7/0x710 [ 345.638442] [<c13b3b19>] ? __netif_receive_skb_core+0x69/0x710 [ 345.638454] [<c13b41e1>] ? __netif_receive_skb+0x21/0x70 [ 345.638464] [<c13b42b5>] ? process_backlog+0x85/0x130 [ 345.638476] [<c13b4bbb>] ? net_rx_action+0xfb/0x1d0 [ 345.638497] [<c1032768>] ? __do_softirq+0xa8/0x1f0 [ 345.638527] [<c147daad>] ? _raw_spin_unlock+0x1d/0x20 [ 345.638538] [<c10038c0>] ? handle_irq+0x20/0xd0 [ 345.638550] [<c1032f27>] ? irq_exit+0x97/0xa0 [ 345.638560] [<c1003632>] ? do_IRQ+0x42/0xa0 [ 345.638580] [<c104d003>] ? hrtimer_start+0x23/0x30 [ 345.638580] [<c1484631>] ? common_interrupt+0x31/0x36 [ 345.638580] [<c1008703>] ? default_idle+0x33/0xc0 [ 345.638580] [<c10086ac>] ? cpu_idle+0x4c/0x70 [ 345.638580] [<c14787e0>] ? rest_init+0xa0/0xb0 [ 345.638580] [<c1478740>] ? reciprocal_value+0x50/0x50 [ 345.638580] [<c16b5bcf>] ? start_kernel+0x28f/0x320 [ 345.638580] [<c16b54e0>] ? repair_env_string+0x60/0x60 [ 345.638580] [<c16b5269>] ? i386_start_kernel+0x39/0xa0 [ 345.638580] ---[ end trace a244264b69b8a7ae ]--- [ 345.638580] Mapped at: [ 345.638580] [<c1221c65>] debug_dma_map_page+0x65/0x110 [ 345.638580] [<cf8355a9>] sis900_start_xmit+0x129/0x210 [sis900] [ 345.638580] [<c13b2527>] dev_hard_start_xmit+0x1b7/0x530 [ 345.638580] [<c13cc32e>] sch_direct_xmit+0x8e/0x280 [ 345.638580] [<c13b4e39>] dev_queue_xmit+0x1a9/0x5b0 Signed-off-by: Denis Kirjanov <[email protected]> Signed-off-by: David S. Miller <[email protected]>

This fixes the following lockdep splat: [ 66.460000] ================================= [ 66.460000] [ INFO: inconsistent lock state ] [ 66.460000] 3.9.0-rc5-00161-ga48dd49 #4 Not tainted [ 66.460000] --------------------------------- [ 66.460000] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 66.460000] swapper/1 [HC0[0]:SC1[1]:HE1:SE0] takes: [ 66.460000] (timer_lock){+.?...}, at: [<d0006cde>] rs_poll+0x12/0xdc [ 66.460000] {SOFTIRQ-ON-W} state was registered at: [ 66.460000] [<d00421f0>] lock_acquire+0xec/0x13c [ 66.460000] [<d01ea036>] _raw_spin_lock+0x3a/0x84 [ 66.460000] [<d0006c8c>] rs_open+0x18/0x58 [ 66.460000] [<d0139ea2>] tty_open+0x262/0x3cc [ 66.460000] [<d00942e0>] chrdev_open+0x8c/0xe0 [ 66.460000] [<d00907b2>] do_dentry_open$isra$16+0x10e/0x190 [ 66.460000] [<d0091141>] finish_open+0x39/0x48 [ 66.460000] [<d009a0b4>] do_last$isra$34+0x6c4/0x824 [ 66.460000] [<d009a27a>] path_openat+0x66/0x310 [ 66.460000] [<d009a53a>] do_filp_open+0x16/0x44 [ 66.460000] [<d0091445>] do_sys_open+0xd5/0x13c [ 66.460000] [<d00914be>] sys_open+0x12/0x18 [ 66.460000] [<d0413ffc>] kernel_init_freeable+0xe4/0x12c [ 66.460000] [<d01e2a9c>] kernel_init+0xc/0x9c [ 66.460000] [<d00044fc>] ret_from_kernel_thread+0x8/0xc [ 66.460000] irq event stamp: 132542 [ 66.460000] hardirqs last enabled at (132542): [<d01ea2ec>] _raw_spin_unlock_irq+0x30/0x44 [ 66.460000] hardirqs last disabled at (132541): [<d01ea11e>] _raw_spin_lock_irq+0xe/0x8c [ 66.460000] softirqs last enabled at (132234): [<d0017d32>] __do_softirq+0x216/0x2a4 [ 66.460000] softirqs last disabled at (132539): [<d0018024>] irq_exit+0x38/0x40 [ 66.460000] [ 66.460000] other info that might help us debug this: [ 66.460000] Possible unsafe locking scenario: [ 66.460000] [ 66.460000] CPU0 [ 66.460000] ---- [ 66.460000] lock(timer_lock); [ 66.460000] <Interrupt> [ 66.460000] lock(timer_lock); [ 66.460000] [ 66.460000] *** DEADLOCK *** [ 66.460000] [ 66.460000] 1 lock held by swapper/1: [ 66.460000] #0: (((&serial_timer))){+.-...}, at: [<d001c65c>] call_timer_fn+0x0/0x1f0 [ 66.460000] Stack: d7c2fac0 00000018 00000004 00000001 d7c2faa0 00000004 00000006 d7c2fa90 9003e87c d7c2fae0 d7c30000 d025a87c 00000001 0000000f 00000000 d7c2fac0 9004005d d7c2fb10 d7c30000 d7c30338 00000001 00000001 00000000 d7c30338 [ 66.460000] Call Trace: [ 66.460000] [<d01e4f93>] print_usage_bug$part$26+0x1c3/0x1c8 [ 66.460000] [<d003e87c>] mark_lock+0x2b4/0x440 [ 66.460000] [<d004005d>] __lock_acquire+0x54d/0x16c4 [ 66.460000] [<d00421f0>] lock_acquire+0xec/0x13c [ 66.460000] [<d01ea036>] _raw_spin_lock+0x3a/0x84 [ 66.460000] [<d0006cde>] rs_poll+0x12/0xdc [ 66.460000] [<d001c71a>] call_timer_fn+0xbe/0x1f0 [ 66.460000] [<d001cd90>] run_timer_softirq+0x198/0x1f4 [ 66.460000] [<d0017c30>] __do_softirq+0x114/0x2a4 [ 66.460000] [<d0018024>] irq_exit+0x38/0x40 [ 66.460000] [<d00046c0>] do_IRQ+0x44/0x48 [ 66.460000] [<d0005c58>] do_interrupt+0x4c/0x54 [ 66.460000] [<d0003c80>] common_exception_return+0x0/0x5c [ 66.460000] [<d006682c>] free_pcppages_bulk+0x254/0x308 [ 66.460000] Signed-off-by: Max Filippov <[email protected]> Signed-off-by: Chris Zankel <[email protected]>

This can easily be triggered if a new CPU is added (via ACPI hotplug mechanism) and from user-space you do: echo 1 > /sys/devices/system/cpu/cpu3/online (or wait for UDEV to do it) on a newly appeared physical CPU. The deadlock is that the "store_online" in drivers/base/cpu.c takes the cpu_hotplug_driver_lock() lock, then calls "cpu_up". "cpu_up" eventually ends up calling "save_mc_for_early" which also takes the cpu_hotplug_driver_lock() lock. And here is that lockdep thinks of it: smpboot: Stack at about ffff880075c39f44 smpboot: CPU3: has booted. microcode: CPU3 sig=0x206a7, pf=0x2, revision=0x25 ============================================= [ INFO: possible recursive locking detected ] 3.9.0upstream-10129-g167af0e #1 Not tainted --------------------------------------------- sh/2487 is trying to acquire lock: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff81075512>] cpu_hotplug_driver_lock+0x12/0x20 but task is already holding lock: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff81075512>] cpu_hotplug_driver_lock+0x12/0x20 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(x86_cpu_hotplug_driver_mutex); lock(x86_cpu_hotplug_driver_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by sh/2487: #0: (sb_writers#5){.+.+.+}, at: [<ffffffff811ca48d>] vfs_write+0x17d/0x190 #1: (&buffer->mutex){+.+.+.}, at: [<ffffffff812464ef>] sysfs_write_file+0x3f/0x160 #2: (s_active#20){.+.+.+}, at: [<ffffffff81246578>] sysfs_write_file+0xc8/0x160 #3: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff81075512>] cpu_hotplug_driver_lock+0x12/0x20 #4: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff810961c2>] cpu_maps_update_begin+0x12/0x20 #5: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff810962a7>] cpu_hotplug_begin+0x27/0x60 Suggested-and-Acked-by: Borislav Petkov <[email protected]> Signed-off-by: Konrad Rzeszutek Wilk <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] # for v3.9 Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>

Daniel Petre reported crashes in icmp_dst_unreach() with following call graph: #3 [ffff88003fc03938] __stack_chk_fail at ffffffff81037f77 #4 [ffff88003fc03948] icmp_send at ffffffff814d5fec #5 [ffff88003fc03ae8] ipv4_link_failure at ffffffff814a1795 torvalds#6 [ffff88003fc03af8] ipgre_tunnel_xmit at ffffffff814e7965 torvalds#7 [ffff88003fc03b78] dev_hard_start_xmit at ffffffff8146e032 torvalds#8 [ffff88003fc03bc8] sch_direct_xmit at ffffffff81487d66 torvalds#9 [ffff88003fc03c08] __qdisc_run at ffffffff81487efd torvalds#10 [ffff88003fc03c48] dev_queue_xmit at ffffffff8146e5a7 torvalds#11 [ffff88003fc03c88] ip_finish_output at ffffffff814ab596 Daniel found a similar problem mentioned in http://lkml.indiana.edu/hypermail/linux/kernel/1007.0/00961.html And indeed this is the root cause : skb->cb[] contains data fooling IP stack. We must clear IPCB in ip_tunnel_xmit() sooner in case dst_link_failure() is called. Or else skb->cb[] might contain garbage from GSO segmentation layer. A similar fix was tested on linux-3.9, but gre code was refactored in linux-3.10. I'll send patches for stable kernels as well. Many thanks to Daniel for providing reports, patches and testing ! Reported-by: Daniel Petre <[email protected]> Signed-off-by: Eric Dumazet <[email protected]> Signed-off-by: David S. Miller <[email protected]>

Commit be283b2 ( Btrfs: use helper to cleanup tree roots) introduced the following bug, BUG: unable to handle kernel NULL pointer dereference at 0000000000000034 IP: [<ffffffffa039368c>] extent_buffer_get+0x4/0xa [btrfs] [...] Pid: 2463, comm: btrfs-cache-1 Tainted: G O 3.9.0+ #4 innotek GmbH VirtualBox/VirtualBox RIP: 0010:[<ffffffffa039368c>] [<ffffffffa039368c>] extent_buffer_get+0x4/0xa [btrfs] Process btrfs-cache-1 (pid: 2463, threadinfo ffff880112d60000, task ffff880117679730) [...] Call Trace: [<ffffffffa0398a99>] btrfs_search_slot+0x104/0x64d [btrfs] [<ffffffffa039aea4>] btrfs_next_old_leaf+0xa7/0x334 [btrfs] [<ffffffffa039b141>] btrfs_next_leaf+0x10/0x12 [btrfs] [<ffffffffa039ea13>] caching_thread+0x1a3/0x2e0 [btrfs] [<ffffffffa03d8811>] worker_loop+0x14b/0x48e [btrfs] [<ffffffffa03d86c6>] ? btrfs_queue_worker+0x25c/0x25c [btrfs] [<ffffffff81068d3d>] kthread+0x8d/0x95 [<ffffffff81068cb0>] ? kthread_freezable_should_stop+0x43/0x43 [<ffffffff8151e5ac>] ret_from_fork+0x7c/0xb0 [<ffffffff81068cb0>] ? kthread_freezable_should_stop+0x43/0x43 RIP [<ffffffffa039368c>] extent_buffer_get+0x4/0xa [btrfs] We've free'ed commit_root before actually getting to free block groups where caching thread needs valid extent_root->commit_root. Signed-off-by: Liu Bo <[email protected]> Signed-off-by: Josef Bacik <[email protected]> Signed-off-by: Chris Mason <[email protected]>

This commit fixes a lockdep-detected deadlock by moving a wake_up() call out from a rnp->lock critical section. Please see below for the long version of this story. On Tue, 2013-05-28 at 16:13 -0400, Dave Jones wrote: > [12572.705832] ====================================================== > [12572.750317] [ INFO: possible circular locking dependency detected ] > [12572.796978] 3.10.0-rc3+ torvalds#39 Not tainted > [12572.833381] ------------------------------------------------------- > [12572.862233] trinity-child17/31341 is trying to acquire lock: > [12572.870390] (rcu_node_0){..-.-.}, at: [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12572.878859] > but task is already holding lock: > [12572.894894] (&ctx->lock){-.-...}, at: [<ffffffff811390ed>] perf_lock_task_context+0x7d/0x2d0 > [12572.903381] > which lock already depends on the new lock. > > [12572.927541] > the existing dependency chain (in reverse order) is: > [12572.943736] > -> #4 (&ctx->lock){-.-...}: > [12572.960032] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12572.968337] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12572.976633] [<ffffffff8113c987>] __perf_event_task_sched_out+0x2e7/0x5e0 > [12572.984969] [<ffffffff81088953>] perf_event_task_sched_out+0x93/0xa0 > [12572.993326] [<ffffffff816ea0bf>] __schedule+0x2cf/0x9c0 > [12573.001652] [<ffffffff816eacfe>] schedule_user+0x2e/0x70 > [12573.009998] [<ffffffff816ecd64>] retint_careful+0x12/0x2e > [12573.018321] > -> #3 (&rq->lock){-.-.-.}: > [12573.034628] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.042930] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.051248] [<ffffffff8108e6a7>] wake_up_new_task+0xb7/0x260 > [12573.059579] [<ffffffff810492f5>] do_fork+0x105/0x470 > [12573.067880] [<ffffffff81049686>] kernel_thread+0x26/0x30 > [12573.076202] [<ffffffff816cee63>] rest_init+0x23/0x140 > [12573.084508] [<ffffffff81ed8e1f>] start_kernel+0x3f1/0x3fe > [12573.092852] [<ffffffff81ed856f>] x86_64_start_reservations+0x2a/0x2c > [12573.101233] [<ffffffff81ed863d>] x86_64_start_kernel+0xcc/0xcf > [12573.109528] > -> #2 (&p->pi_lock){-.-.-.}: > [12573.125675] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.133829] [<ffffffff816ebe9b>] _raw_spin_lock_irqsave+0x4b/0x90 > [12573.141964] [<ffffffff8108e881>] try_to_wake_up+0x31/0x320 > [12573.150065] [<ffffffff8108ebe2>] default_wake_function+0x12/0x20 > [12573.158151] [<ffffffff8107bbf8>] autoremove_wake_function+0x18/0x40 > [12573.166195] [<ffffffff81085398>] __wake_up_common+0x58/0x90 > [12573.174215] [<ffffffff81086909>] __wake_up+0x39/0x50 > [12573.182146] [<ffffffff810fc3da>] rcu_start_gp_advanced.isra.11+0x4a/0x50 > [12573.190119] [<ffffffff810fdb09>] rcu_start_future_gp+0x1c9/0x1f0 > [12573.198023] [<ffffffff810fe2c4>] rcu_nocb_kthread+0x114/0x930 > [12573.205860] [<ffffffff8107a91d>] kthread+0xed/0x100 > [12573.213656] [<ffffffff816f4b1c>] ret_from_fork+0x7c/0xb0 > [12573.221379] > -> #1 (&rsp->gp_wq){..-.-.}: > [12573.236329] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.243783] [<ffffffff816ebe9b>] _raw_spin_lock_irqsave+0x4b/0x90 > [12573.251178] [<ffffffff810868f3>] __wake_up+0x23/0x50 > [12573.258505] [<ffffffff810fc3da>] rcu_start_gp_advanced.isra.11+0x4a/0x50 > [12573.265891] [<ffffffff810fdb09>] rcu_start_future_gp+0x1c9/0x1f0 > [12573.273248] [<ffffffff810fe2c4>] rcu_nocb_kthread+0x114/0x930 > [12573.280564] [<ffffffff8107a91d>] kthread+0xed/0x100 > [12573.287807] [<ffffffff816f4b1c>] ret_from_fork+0x7c/0xb0 Notice the above call chain. rcu_start_future_gp() is called with the rnp->lock held. Then it calls rcu_start_gp_advance, which does a wakeup. You can't do wakeups while holding the rnp->lock, as that would mean that you could not do a rcu_read_unlock() while holding the rq lock, or any lock that was taken while holding the rq lock. This is because... (See below). > [12573.295067] > -> #0 (rcu_node_0){..-.-.}: > [12573.309293] [<ffffffff810b8d36>] __lock_acquire+0x1786/0x1af0 > [12573.316568] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.323825] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.331081] [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12573.338377] [<ffffffff810760a6>] __rcu_read_unlock+0x96/0xa0 > [12573.345648] [<ffffffff811391b3>] perf_lock_task_context+0x143/0x2d0 > [12573.352942] [<ffffffff8113938e>] find_get_context+0x4e/0x1f0 > [12573.360211] [<ffffffff811403f4>] SYSC_perf_event_open+0x514/0xbd0 > [12573.367514] [<ffffffff81140e49>] SyS_perf_event_open+0x9/0x10 > [12573.374816] [<ffffffff816f4dd4>] tracesys+0xdd/0xe2 Notice the above trace. perf took its own ctx->lock, which can be taken while holding the rq lock. While holding this lock, it did a rcu_read_unlock(). The perf_lock_task_context() basically looks like: rcu_read_lock(); raw_spin_lock(ctx->lock); rcu_read_unlock(); Now, what looks to have happened, is that we scheduled after taking that first rcu_read_lock() but before taking the spin lock. When we scheduled back in and took the ctx->lock, the following rcu_read_unlock() triggered the "special" code. The rcu_read_unlock_special() takes the rnp->lock, which gives us a possible deadlock scenario. CPU0 CPU1 CPU2 ---- ---- ---- rcu_nocb_kthread() lock(rq->lock); lock(ctx->lock); lock(rnp->lock); wake_up(); lock(rq->lock); rcu_read_unlock(); rcu_read_unlock_special(); lock(rnp->lock); lock(ctx->lock); **** DEADLOCK **** > [12573.382068] > other info that might help us debug this: > > [12573.403229] Chain exists of: > rcu_node_0 --> &rq->lock --> &ctx->lock > > [12573.424471] Possible unsafe locking scenario: > > [12573.438499] CPU0 CPU1 > [12573.445599] ---- ---- > [12573.452691] lock(&ctx->lock); > [12573.459799] lock(&rq->lock); > [12573.467010] lock(&ctx->lock); > [12573.474192] lock(rcu_node_0); > [12573.481262] > *** DEADLOCK *** > > [12573.501931] 1 lock held by trinity-child17/31341: > [12573.508990] #0: (&ctx->lock){-.-...}, at: [<ffffffff811390ed>] perf_lock_task_context+0x7d/0x2d0 > [12573.516475] > stack backtrace: > [12573.530395] CPU: 1 PID: 31341 Comm: trinity-child17 Not tainted 3.10.0-rc3+ torvalds#39 > [12573.545357] ffffffff825b4f90 ffff880219f1dbc0 ffffffff816e375b ffff880219f1dc00 > [12573.552868] ffffffff816dfa5d ffff880219f1dc50 ffff88023ce4d1f8 ffff88023ce4ca40 > [12573.560353] 0000000000000001 0000000000000001 ffff88023ce4d1f8 ffff880219f1dcc0 > [12573.567856] Call Trace: > [12573.575011] [<ffffffff816e375b>] dump_stack+0x19/0x1b > [12573.582284] [<ffffffff816dfa5d>] print_circular_bug+0x200/0x20f > [12573.589637] [<ffffffff810b8d36>] __lock_acquire+0x1786/0x1af0 > [12573.596982] [<ffffffff810918f5>] ? sched_clock_cpu+0xb5/0x100 > [12573.604344] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.611652] [<ffffffff811054ff>] ? rcu_read_unlock_special+0x9f/0x4c0 > [12573.619030] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.626331] [<ffffffff811054ff>] ? rcu_read_unlock_special+0x9f/0x4c0 > [12573.633671] [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12573.640992] [<ffffffff811390ed>] ? perf_lock_task_context+0x7d/0x2d0 > [12573.648330] [<ffffffff810b429e>] ? put_lock_stats.isra.29+0xe/0x40 > [12573.655662] [<ffffffff813095a0>] ? delay_tsc+0x90/0xe0 > [12573.662964] [<ffffffff810760a6>] __rcu_read_unlock+0x96/0xa0 > [12573.670276] [<ffffffff811391b3>] perf_lock_task_context+0x143/0x2d0 > [12573.677622] [<ffffffff81139070>] ? __perf_event_enable+0x370/0x370 > [12573.684981] [<ffffffff8113938e>] find_get_context+0x4e/0x1f0 > [12573.692358] [<ffffffff811403f4>] SYSC_perf_event_open+0x514/0xbd0 > [12573.699753] [<ffffffff8108cd9d>] ? get_parent_ip+0xd/0x50 > [12573.707135] [<ffffffff810b71fd>] ? trace_hardirqs_on_caller+0xfd/0x1c0 > [12573.714599] [<ffffffff81140e49>] SyS_perf_event_open+0x9/0x10 > [12573.721996] [<ffffffff816f4dd4>] tracesys+0xdd/0xe2 This commit delays the wakeup via irq_work(), which is what perf and ftrace use to perform wakeups in critical sections. Reported-by: Dave Jones <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]>

In Steven Rostedt's words: > I've been debugging the last couple of days why my tests have been > locking up. One of my tracing tests, runs all available tracers. The > lockup always happened with the mmiotrace, which is used to trace > interactions between priority drivers and the kernel. But to do this > easily, when the tracer gets registered, it disables all but the boot > CPUs. The lockup always happened after it got done disabling the CPUs. > > Then I decided to try this: > > while :; do > for i in 1 2 3; do > echo 0 > /sys/devices/system/cpu/cpu$i/online > done > for i in 1 2 3; do > echo 1 > /sys/devices/system/cpu/cpu$i/online > done > done > > Well, sure enough, that locked up too, with the same users. Doing a > sysrq-w (showing all blocked tasks): > > [ 2991.344562] task PC stack pid father > [ 2991.344562] rcu_preempt D ffff88007986fdf8 0 10 2 0x00000000 > [ 2991.344562] ffff88007986fc98 0000000000000002 ffff88007986fc48 0000000000000908 > [ 2991.344562] ffff88007986c280 ffff88007986ffd8 ffff88007986ffd8 00000000001d3c80 > [ 2991.344562] ffff880079248a40 ffff88007986c280 0000000000000000 00000000fffd4295 > [ 2991.344562] Call Trace: > [ 2991.344562] [<ffffffff815437ba>] schedule+0x64/0x66 > [ 2991.344562] [<ffffffff81541750>] schedule_timeout+0xbc/0xf9 > [ 2991.344562] [<ffffffff8154bec0>] ? ftrace_call+0x5/0x2f > [ 2991.344562] [<ffffffff81049513>] ? cascade+0xa8/0xa8 > [ 2991.344562] [<ffffffff815417ab>] schedule_timeout_uninterruptible+0x1e/0x20 > [ 2991.344562] [<ffffffff810c980c>] rcu_gp_kthread+0x502/0x94b > [ 2991.344562] [<ffffffff81062791>] ? __init_waitqueue_head+0x50/0x50 > [ 2991.344562] [<ffffffff810c930a>] ? rcu_gp_fqs+0x64/0x64 > [ 2991.344562] [<ffffffff81061cdb>] kthread+0xb1/0xb9 > [ 2991.344562] [<ffffffff81091e31>] ? lock_release_holdtime.part.23+0x4e/0x55 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] [<ffffffff8154c1dc>] ret_from_fork+0x7c/0xb0 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] kworker/0:1 D ffffffff81a30680 0 47 2 0x00000000 > [ 2991.344562] Workqueue: events cpuset_hotplug_workfn > [ 2991.344562] ffff880078dbbb58 0000000000000002 0000000000000006 00000000000000d8 > [ 2991.344562] ffff880078db8100 ffff880078dbbfd8 ffff880078dbbfd8 00000000001d3c80 > [ 2991.344562] ffff8800779ca5c0 ffff880078db8100 ffffffff81541fcf 0000000000000000 > [ 2991.344562] Call Trace: > [ 2991.344562] [<ffffffff81541fcf>] ? __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff815437ba>] schedule+0x64/0x66 > [ 2991.344562] [<ffffffff81543a39>] schedule_preempt_disabled+0x18/0x24 > [ 2991.344562] [<ffffffff81541fcf>] __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff8103d11b>] ? get_online_cpus+0x3c/0x50 > [ 2991.344562] [<ffffffff8103d11b>] ? get_online_cpus+0x3c/0x50 > [ 2991.344562] [<ffffffff815422ff>] mutex_lock_nested+0x3b/0x40 > [ 2991.344562] [<ffffffff8103d11b>] get_online_cpus+0x3c/0x50 > [ 2991.344562] [<ffffffff810af7e6>] rebuild_sched_domains_locked+0x6e/0x3a8 > [ 2991.344562] [<ffffffff810b0ec6>] rebuild_sched_domains+0x1c/0x2a > [ 2991.344562] [<ffffffff810b109b>] cpuset_hotplug_workfn+0x1c7/0x1d3 > [ 2991.344562] [<ffffffff810b0ed9>] ? cpuset_hotplug_workfn+0x5/0x1d3 > [ 2991.344562] [<ffffffff81058e07>] process_one_work+0x2d4/0x4d1 > [ 2991.344562] [<ffffffff81058d3a>] ? process_one_work+0x207/0x4d1 > [ 2991.344562] [<ffffffff8105964c>] worker_thread+0x2e7/0x3b5 > [ 2991.344562] [<ffffffff81059365>] ? rescuer_thread+0x332/0x332 > [ 2991.344562] [<ffffffff81061cdb>] kthread+0xb1/0xb9 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] [<ffffffff8154c1dc>] ret_from_fork+0x7c/0xb0 > [ 2991.344562] [<ffffffff81061c2a>] ? __init_kthread_worker+0x58/0x58 > [ 2991.344562] bash D ffffffff81a4aa80 0 2618 2612 0x10000000 > [ 2991.344562] ffff8800379abb58 0000000000000002 0000000000000006 0000000000000c2c > [ 2991.344562] ffff880077fea140 ffff8800379abfd8 ffff8800379abfd8 00000000001d3c80 > [ 2991.344562] ffff8800779ca5c0 ffff880077fea140 ffffffff81541fcf 0000000000000000 > [ 2991.344562] Call Trace: > [ 2991.344562] [<ffffffff81541fcf>] ? __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff815437ba>] schedule+0x64/0x66 > [ 2991.344562] [<ffffffff81543a39>] schedule_preempt_disabled+0x18/0x24 > [ 2991.344562] [<ffffffff81541fcf>] __mutex_lock_common+0x3d4/0x609 > [ 2991.344562] [<ffffffff81530078>] ? rcu_cpu_notify+0x2f5/0x86e > [ 2991.344562] [<ffffffff81530078>] ? rcu_cpu_notify+0x2f5/0x86e > [ 2991.344562] [<ffffffff815422ff>] mutex_lock_nested+0x3b/0x40 > [ 2991.344562] [<ffffffff81530078>] rcu_cpu_notify+0x2f5/0x86e > [ 2991.344562] [<ffffffff81091c99>] ? __lock_is_held+0x32/0x53 > [ 2991.344562] [<ffffffff81548912>] notifier_call_chain+0x6b/0x98 > [ 2991.344562] [<ffffffff810671fd>] __raw_notifier_call_chain+0xe/0x10 > [ 2991.344562] [<ffffffff8103cf64>] __cpu_notify+0x20/0x32 > [ 2991.344562] [<ffffffff8103cf8d>] cpu_notify_nofail+0x17/0x36 > [ 2991.344562] [<ffffffff815225de>] _cpu_down+0x154/0x259 > [ 2991.344562] [<ffffffff81522710>] cpu_down+0x2d/0x3a > [ 2991.344562] [<ffffffff81526351>] store_online+0x4e/0xe7 > [ 2991.344562] [<ffffffff8134d764>] dev_attr_store+0x20/0x22 > [ 2991.344562] [<ffffffff811b3c5f>] sysfs_write_file+0x108/0x144 > [ 2991.344562] [<ffffffff8114c5ef>] vfs_write+0xfd/0x158 > [ 2991.344562] [<ffffffff8114c928>] SyS_write+0x5c/0x83 > [ 2991.344562] [<ffffffff8154c494>] tracesys+0xdd/0xe2 > > As well as held locks: > > [ 3034.728033] Showing all locks held in the system: > [ 3034.728033] 1 lock held by rcu_preempt/10: > [ 3034.728033] #0: (rcu_preempt_state.onoff_mutex){+.+...}, at: [<ffffffff810c9471>] rcu_gp_kthread+0x167/0x94b > [ 3034.728033] 4 locks held by kworker/0:1/47: > [ 3034.728033] #0: (events){.+.+.+}, at: [<ffffffff81058d3a>] process_one_work+0x207/0x4d1 > [ 3034.728033] #1: (cpuset_hotplug_work){+.+.+.}, at: [<ffffffff81058d3a>] process_one_work+0x207/0x4d1 > [ 3034.728033] #2: (cpuset_mutex){+.+.+.}, at: [<ffffffff810b0ec1>] rebuild_sched_domains+0x17/0x2a > [ 3034.728033] #3: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8103d11b>] get_online_cpus+0x3c/0x50 > [ 3034.728033] 1 lock held by mingetty/2563: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2565: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2569: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2572: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 1 lock held by mingetty/2575: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > [ 3034.728033] 7 locks held by bash/2618: > [ 3034.728033] #0: (sb_writers#5){.+.+.+}, at: [<ffffffff8114bc3f>] file_start_write+0x2a/0x2c > [ 3034.728033] #1: (&buffer->mutex#2){+.+.+.}, at: [<ffffffff811b3b93>] sysfs_write_file+0x3c/0x144 > [ 3034.728033] #2: (s_active#54){.+.+.+}, at: [<ffffffff811b3c3e>] sysfs_write_file+0xe7/0x144 > [ 3034.728033] #3: (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff810217c2>] cpu_hotplug_driver_lock+0x17/0x19 > [ 3034.728033] #4: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff8103d196>] cpu_maps_update_begin+0x17/0x19 > [ 3034.728033] #5: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8103cfd8>] cpu_hotplug_begin+0x2c/0x6d > [ 3034.728033] torvalds#6: (rcu_preempt_state.onoff_mutex){+.+...}, at: [<ffffffff81530078>] rcu_cpu_notify+0x2f5/0x86e > [ 3034.728033] 1 lock held by bash/2980: > [ 3034.728033] #0: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8131e28a>] n_tty_read+0x252/0x7e8 > > Things looked a little weird. Also, this is a deadlock that lockdep did > not catch. But what we have here does not look like a circular lock > issue: > > Bash is blocked in rcu_cpu_notify(): > > 1961 /* Exclude any attempts to start a new grace period. */ > 1962 mutex_lock(&rsp->onoff_mutex); > > > kworker is blocked in get_online_cpus(), which makes sense as we are > currently taking down a CPU. > > But rcu_preempt is not blocked on anything. It is simply sleeping in > rcu_gp_kthread (really rcu_gp_init) here: > > 1453 #ifdef CONFIG_PROVE_RCU_DELAY > 1454 if ((prandom_u32() % (rcu_num_nodes * 8)) == 0 && > 1455 system_state == SYSTEM_RUNNING) > 1456 schedule_timeout_uninterruptible(2); > 1457 #endif /* #ifdef CONFIG_PROVE_RCU_DELAY */ > > And it does this while holding the onoff_mutex that bash is waiting for. > > Doing a function trace, it showed me where it happened: > > [ 125.940066] rcu_pree-10 3.... 28384115273: schedule_timeout_uninterruptible <-rcu_gp_kthread > [...] > [ 125.940066] rcu_pree-10 3d..3 28384202439: sched_switch: prev_comm=rcu_preempt prev_pid=10 prev_prio=120 prev_state=D ==> next_comm=watchdog/3 next_pid=38 next_prio=120 > > The watchdog ran, and then: > > [ 125.940066] watchdog-38 3d..3 28384692863: sched_switch: prev_comm=watchdog/3 prev_pid=38 prev_prio=120 prev_state=P ==> next_comm=modprobe next_pid=2848 next_prio=118 > > Not sure what modprobe was doing, but shortly after that: > > [ 125.940066] modprobe-2848 3d..3 28385041749: sched_switch: prev_comm=modprobe prev_pid=2848 prev_prio=118 prev_state=R+ ==> next_comm=migration/3 next_pid=40 next_prio=0 > > Where the migration thread took down the CPU: > > [ 125.940066] migratio-40 3d..3 28389148276: sched_switch: prev_comm=migration/3 prev_pid=40 prev_prio=0 prev_state=P ==> next_comm=swapper/3 next_pid=0 next_prio=120 > > which finally did: > > [ 125.940066] <idle>-0 3...1 28389282142: arch_cpu_idle_dead <-cpu_startup_entry > [ 125.940066] <idle>-0 3...1 28389282548: native_play_dead <-arch_cpu_idle_dead > [ 125.940066] <idle>-0 3...1 28389282924: play_dead_common <-native_play_dead > [ 125.940066] <idle>-0 3...1 28389283468: idle_task_exit <-play_dead_common > [ 125.940066] <idle>-0 3...1 28389284644: amd_e400_remove_cpu <-play_dead_common > > > CPU 3 is now offline, the rcu_preempt thread that ran on CPU 3 is still > doing a schedule_timeout_uninterruptible() and it registered it's > timeout to the timer base for CPU 3. You would think that it would get > migrated right? The issue here is that the timer migration happens at > the CPU notifier for CPU_DEAD. The problem is that the rcu notifier for > CPU_DOWN is blocked waiting for the onoff_mutex to be released, which is > held by the thread that just put itself into a uninterruptible sleep, > that wont wake up until the CPU_DEAD notifier of the timer > infrastructure is called, which wont happen until the rcu notifier > finishes. Here's our deadlock! This commit breaks this deadlock cycle by substituting a shorter udelay() for the previous schedule_timeout_uninterruptible(), while at the same time increasing the probability of the delay. This maintains the intensity of the testing. Reported-by: Steven Rostedt <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Tested-by: Steven Rostedt <[email protected]>

(This is a VERY IMP change for low level interrupt/exception handling) ----------------------------------------------------------------------- WHAT ----------------------------------------------------------------------- * User 25 now saved in pt_regs->user_r25 (vs. tsk->thread_info.user_r25) * This allows Low level interrupt code to unconditionally save r25 (vs. the prev version which would only do it for U->K transition). Ofcourse for nested interrupts, only the pt_regs->user_r25 of bottom-most frame is useful. * simplifies the interrupt prologue/epilogue * Needed for ARCv2 ISA code and done here to keep design similar with ARCompact event handling ----------------------------------------------------------------------- WHY ------------------------------------------------------------------------- With CONFIG_ARC_CURR_IN_REG, r25 is used to cache "current" task pointer in kernel mode. So when entering kernel mode from User Mode - user r25 is specially safe-kept (it being a callee reg is NOT part of pt_regs which are saved by default on each interrupt/trap/exception) - r25 loaded with current task pointer. Further, if interrupt was taken in kernel mode, this is skipped since we know that r25 already has valid "current" pointer. With 2 level of interrupts in ARCompact ISA, detecting this is difficult but still possible, since we could be in kernel mode but r25 not already saved (in fact the stack itself might not have been switched). A. User mode B. L1 IRQ taken C. L2 IRQ taken (while on 1st line of L1 ISR) So in #C, although in kernel mode, r25 not saved (infact SP not switched at all) Given that ARcompact has manual stack switching, we could use a bit of trickey - The low level code would make sure that SP is only set to kernel mode value at the very end (after saving r25). So a non kernel mode SP, even if in kernel mode, meant r25 was NOT saved. The same paradigm won't work in ARCv2 ISA since SP is auto-switched so it's setting can't be delayed/constrained. Signed-off-by: Vineet Gupta <[email protected]>

@Write

…/kernel/git/vgupta/arc Pull first batch of ARC changes from Vineet Gupta: "There's a second bunch to follow next week - which depends on commits on other trees (irq/net). I'd have preferred the accompanying ARC change via respective trees, but it didn't workout somehow. Highlights of changes: - Continuation of ARC MM changes from 3.10 including zero page optimization Setting pagecache pages dirty by default Non executable stack by default Reducing dcache flushes for aliasing VIPT config - Long overdue rework of pt_regs machinery - removing the unused word gutters and adding ECR register to baseline (helps cleanup lot of low level code) - Support for ARC gcc 4.8 - Few other preventive fixes, cosmetics, usage of Kconfig helper.. The diffstat is larger than normal primarily because of arcregs.h header split as well as beautification of macros in entry.h" * tag 'arc-v3.11-rc1-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (32 commits) ARC: warn on improper stack unwind FDE entries arc: delete __cpuinit usage from all arc files ARC: [tlb-miss] Fix bug with CONFIG_ARC_DBG_TLB_MISS_COUNT ARC: [tlb-miss] Extraneous PTE bit testing/setting ARC: Adjustments for gcc 4.8 ARC: Setup Vector Table Base in early boot ARC: Remove explicit passing around of ECR ARC: pt_regs update #5: Use real ECR for pt_regs->event vs. synth values ARC: stop using pt_regs->orig_r8 ARC: pt_regs update #4: r25 saved/restored unconditionally ARC: K/U SP saved from one location in stack switching macro ARC: Entry Handler tweaks: Simplify branch for in-kernel preemption ARC: Entry Handler tweaks: Avoid hardcoded LIMMS for ECR values ARC: Increase readability of entry handlers ARC: pt_regs update #3: Remove unused gutter at start of callee_regs ARC: pt_regs update #2: Remove unused gutter at start of pt_regs ARC: pt_regs update #1: Align pt_regs end with end of kernel stack page ARC: pt_regs update #0: remove kernel stack canary ARC: [mm] Remove @Write argument to do_page_fault() ARC: [mm] Make stack/heap Non-executable by default ...

Jiri managed to trigger this warning: [] ====================================================== [] [ INFO: possible circular locking dependency detected ] [] 3.10.0+ torvalds#228 Tainted: G W [] ------------------------------------------------------- [] p/6613 is trying to acquire lock: [] (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250 [] [] but task is already holding lock: [] (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0 [] [] which lock already depends on the new lock. [] [] the existing dependency chain (in reverse order) is: [] [] -> #4 (&ctx->lock){-.-...}: [] -> #3 (&rq->lock){-.-.-.}: [] -> #2 (&p->pi_lock){-.-.-.}: [] -> #1 (&rnp->nocb_gp_wq[1]){......}: [] -> #0 (rcu_node_0){..-...}: Paul was quick to explain that due to preemptible RCU we cannot call rcu_read_unlock() while holding scheduler (or nested) locks when part of the read side critical section was preemptible. Therefore solve it by making the entire RCU read side non-preemptible. Also pull out the retry from under the non-preempt to play nice with RT. Reported-by: Jiri Olsa <[email protected]> Helped-out-by: Paul E. McKenney <[email protected]> Cc: <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>

commit 2f7021a "cpufreq: protect 'policy->cpus' from offlining during __gov_queue_work()" caused a regression in CPU hotplug, because it lead to a deadlock between cpufreq governor worker thread and the CPU hotplug writer task. Lockdep splat corresponding to this deadlock is shown below: [ 60.277396] ====================================================== [ 60.277400] [ INFO: possible circular locking dependency detected ] [ 60.277407] 3.10.0-rc7-dbg-01385-g241fd04-dirty #1744 Not tainted [ 60.277411] ------------------------------------------------------- [ 60.277417] bash/2225 is trying to acquire lock: [ 60.277422] ((&(&j_cdbs->work)->work)){+.+...}, at: [<ffffffff810621b5>] flush_work+0x5/0x280 [ 60.277444] but task is already holding lock: [ 60.277449] (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff81042d8b>] cpu_hotplug_begin+0x2b/0x60 [ 60.277465] which lock already depends on the new lock. [ 60.277472] the existing dependency chain (in reverse order) is: [ 60.277477] -> #2 (cpu_hotplug.lock){+.+.+.}: [ 60.277490] [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200 [ 60.277503] [<ffffffff815b6157>] mutex_lock_nested+0x67/0x410 [ 60.277514] [<ffffffff81042cbc>] get_online_cpus+0x3c/0x60 [ 60.277522] [<ffffffff814b842a>] gov_queue_work+0x2a/0xb0 [ 60.277532] [<ffffffff814b7891>] cs_dbs_timer+0xc1/0xe0 [ 60.277543] [<ffffffff8106302d>] process_one_work+0x1cd/0x6a0 [ 60.277552] [<ffffffff81063d31>] worker_thread+0x121/0x3a0 [ 60.277560] [<ffffffff8106ae2b>] kthread+0xdb/0xe0 [ 60.277569] [<ffffffff815bb96c>] ret_from_fork+0x7c/0xb0 [ 60.277580] -> #1 (&j_cdbs->timer_mutex){+.+...}: [ 60.277592] [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200 [ 60.277600] [<ffffffff815b6157>] mutex_lock_nested+0x67/0x410 [ 60.277608] [<ffffffff814b785d>] cs_dbs_timer+0x8d/0xe0 [ 60.277616] [<ffffffff8106302d>] process_one_work+0x1cd/0x6a0 [ 60.277624] [<ffffffff81063d31>] worker_thread+0x121/0x3a0 [ 60.277633] [<ffffffff8106ae2b>] kthread+0xdb/0xe0 [ 60.277640] [<ffffffff815bb96c>] ret_from_fork+0x7c/0xb0 [ 60.277649] -> #0 ((&(&j_cdbs->work)->work)){+.+...}: [ 60.277661] [<ffffffff810ab826>] __lock_acquire+0x1766/0x1d30 [ 60.277669] [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200 [ 60.277677] [<ffffffff810621ed>] flush_work+0x3d/0x280 [ 60.277685] [<ffffffff81062d8a>] __cancel_work_timer+0x8a/0x120 [ 60.277693] [<ffffffff81062e53>] cancel_delayed_work_sync+0x13/0x20 [ 60.277701] [<ffffffff814b89d9>] cpufreq_governor_dbs+0x529/0x6f0 [ 60.277709] [<ffffffff814b76a7>] cs_cpufreq_governor_dbs+0x17/0x20 [ 60.277719] [<ffffffff814b5df8>] __cpufreq_governor+0x48/0x100 [ 60.277728] [<ffffffff814b6b80>] __cpufreq_remove_dev.isra.14+0x80/0x3c0 [ 60.277737] [<ffffffff815adc0d>] cpufreq_cpu_callback+0x38/0x4c [ 60.277747] [<ffffffff81071a4d>] notifier_call_chain+0x5d/0x110 [ 60.277759] [<ffffffff81071b0e>] __raw_notifier_call_chain+0xe/0x10 [ 60.277768] [<ffffffff815a0a68>] _cpu_down+0x88/0x330 [ 60.277779] [<ffffffff815a0d46>] cpu_down+0x36/0x50 [ 60.277788] [<ffffffff815a2748>] store_online+0x98/0xd0 [ 60.277796] [<ffffffff81452a28>] dev_attr_store+0x18/0x30 [ 60.277806] [<ffffffff811d9edb>] sysfs_write_file+0xdb/0x150 [ 60.277818] [<ffffffff8116806d>] vfs_write+0xbd/0x1f0 [ 60.277826] [<ffffffff811686fc>] SyS_write+0x4c/0xa0 [ 60.277834] [<ffffffff815bbbbe>] tracesys+0xd0/0xd5 [ 60.277842] other info that might help us debug this: [ 60.277848] Chain exists of: (&(&j_cdbs->work)->work) --> &j_cdbs->timer_mutex --> cpu_hotplug.lock [ 60.277864] Possible unsafe locking scenario: [ 60.277869] CPU0 CPU1 [ 60.277873] ---- ---- [ 60.277877] lock(cpu_hotplug.lock); [ 60.277885] lock(&j_cdbs->timer_mutex); [ 60.277892] lock(cpu_hotplug.lock); [ 60.277900] lock((&(&j_cdbs->work)->work)); [ 60.277907] *** DEADLOCK *** [ 60.277915] 6 locks held by bash/2225: [ 60.277919] #0: (sb_writers#6){.+.+.+}, at: [<ffffffff81168173>] vfs_write+0x1c3/0x1f0 [ 60.277937] #1: (&buffer->mutex){+.+.+.}, at: [<ffffffff811d9e3c>] sysfs_write_file+0x3c/0x150 [ 60.277954] #2: (s_active#61){.+.+.+}, at: [<ffffffff811d9ec3>] sysfs_write_file+0xc3/0x150 [ 60.277972] #3: (x86_cpu_hotplug_driver_mutex){+.+...}, at: [<ffffffff81024cf7>] cpu_hotplug_driver_lock+0x17/0x20 [ 60.277990] #4: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff815a0d32>] cpu_down+0x22/0x50 [ 60.278007] #5: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff81042d8b>] cpu_hotplug_begin+0x2b/0x60 [ 60.278023] stack backtrace: [ 60.278031] CPU: 3 PID: 2225 Comm: bash Not tainted 3.10.0-rc7-dbg-01385-g241fd04-dirty #1744 [ 60.278037] Hardware name: Acer Aspire 5741G /Aspire 5741G , BIOS V1.20 02/08/2011 [ 60.278042] ffffffff8204e110 ffff88014df6b9f8 ffffffff815b3d90 ffff88014df6ba38 [ 60.278055] ffffffff815b0a8d ffff880150ed3f60 ffff880150ed4770 3871c4002c8980b2 [ 60.278068] ffff880150ed4748 ffff880150ed4770 ffff880150ed3f60 ffff88014df6bb00 [ 60.278081] Call Trace: [ 60.278091] [<ffffffff815b3d90>] dump_stack+0x19/0x1b [ 60.278101] [<ffffffff815b0a8d>] print_circular_bug+0x2b6/0x2c5 [ 60.278111] [<ffffffff810ab826>] __lock_acquire+0x1766/0x1d30 [ 60.278123] [<ffffffff81067e08>] ? __kernel_text_address+0x58/0x80 [ 60.278134] [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200 [ 60.278142] [<ffffffff810621b5>] ? flush_work+0x5/0x280 [ 60.278151] [<ffffffff810621ed>] flush_work+0x3d/0x280 [ 60.278159] [<ffffffff810621b5>] ? flush_work+0x5/0x280 [ 60.278169] [<ffffffff810a9b14>] ? mark_held_locks+0x94/0x140 [ 60.278178] [<ffffffff81062d77>] ? __cancel_work_timer+0x77/0x120 [ 60.278188] [<ffffffff810a9cbd>] ? trace_hardirqs_on_caller+0xfd/0x1c0 [ 60.278196] [<ffffffff81062d8a>] __cancel_work_timer+0x8a/0x120 [ 60.278206] [<ffffffff81062e53>] cancel_delayed_work_sync+0x13/0x20 [ 60.278214] [<ffffffff814b89d9>] cpufreq_governor_dbs+0x529/0x6f0 [ 60.278225] [<ffffffff814b76a7>] cs_cpufreq_governor_dbs+0x17/0x20 [ 60.278234] [<ffffffff814b5df8>] __cpufreq_governor+0x48/0x100 [ 60.278244] [<ffffffff814b6b80>] __cpufreq_remove_dev.isra.14+0x80/0x3c0 [ 60.278255] [<ffffffff815adc0d>] cpufreq_cpu_callback+0x38/0x4c [ 60.278265] [<ffffffff81071a4d>] notifier_call_chain+0x5d/0x110 [ 60.278275] [<ffffffff81071b0e>] __raw_notifier_call_chain+0xe/0x10 [ 60.278284] [<ffffffff815a0a68>] _cpu_down+0x88/0x330 [ 60.278292] [<ffffffff81024cf7>] ? cpu_hotplug_driver_lock+0x17/0x20 [ 60.278302] [<ffffffff815a0d46>] cpu_down+0x36/0x50 [ 60.278311] [<ffffffff815a2748>] store_online+0x98/0xd0 [ 60.278320] [<ffffffff81452a28>] dev_attr_store+0x18/0x30 [ 60.278329] [<ffffffff811d9edb>] sysfs_write_file+0xdb/0x150 [ 60.278337] [<ffffffff8116806d>] vfs_write+0xbd/0x1f0 [ 60.278347] [<ffffffff81185950>] ? fget_light+0x320/0x4b0 [ 60.278355] [<ffffffff811686fc>] SyS_write+0x4c/0xa0 [ 60.278364] [<ffffffff815bbbbe>] tracesys+0xd0/0xd5 [ 60.280582] smpboot: CPU 1 is now offline The intention of that commit was to avoid warnings during CPU hotplug, which indicated that offline CPUs were getting IPIs from the cpufreq governor's work items. But the real root-cause of that problem was commit a66b2e5 (cpufreq: Preserve sysfs files across suspend/resume) because it totally skipped all the cpufreq callbacks during CPU hotplug in the suspend/resume path, and hence it never actually shut down the cpufreq governor's worker threads during CPU offline in the suspend/resume path. Reflecting back, the reason why we never suspected that commit as the root-cause earlier, was that the original issue was reported with just the halt command and nobody had brought in suspend/resume to the equation. The reason for _that_ in turn, as it turns out, is that earlier halt/shutdown was being done by disabling non-boot CPUs while tasks were frozen, just like suspend/resume.... but commit cf7df37 (reboot: migrate shutdown/reboot to boot cpu) which came somewhere along that very same time changed that logic: shutdown/halt no longer takes CPUs offline. Thus, the test-cases for reproducing the bug were vastly different and thus we went totally off the trail. Overall, it was one hell of a confusion with so many commits affecting each other and also affecting the symptoms of the problems in subtle ways. Finally, now since the original problematic commit (a66b2e5) has been completely reverted, revert this intermediate fix too (2f7021a), to fix the CPU hotplug deadlock. Phew! Reported-by: Sergey Senozhatsky <[email protected]> Reported-by: Bartlomiej Zolnierkiewicz <[email protected]> Signed-off-by: Srivatsa S. Bhat <[email protected]> Tested-by: Peter Wu <[email protected]> Cc: 3.10+ <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]>

Since commit 2025172 (spi/bitbang: Use core message pump), the following kernel crash is seen: Unable to handle kernel NULL pointer dereference at virtual address 0000000d pgd = 80004000 [0000000d] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: CPU: 1 PID: 48 Comm: spi32766 Not tainted 3.11.0-rc1+ #4 task: bfa3e580 ti: bfb90000 task.ti: bfb90000 PC is at spi_bitbang_transfer_one+0x50/0x248 LR is at spi_bitbang_transfer_one+0x20/0x248 ... ,and also the following build warning: drivers/spi/spi-bitbang.c: In function 'spi_bitbang_start': drivers/spi/spi-bitbang.c:436:31: warning: assignment from incompatible pointer type [enabled by default] In order to fix it, we need to change the first parameter of spi_bitbang_transfer_one() to 'struct spi_master *master'. Tested on a mx6qsabrelite by succesfully probing a SPI NOR flash. Signed-off-by: Fabio Estevam <[email protected]> Signed-off-by: Mark Brown <[email protected]>

When we try to open a file with O_TMPFILE flag, we will trigger a bug. The root cause is that in ext4_orphan_add() we check ->i_nlink == 0 and this check always fails because we set ->i_nlink = 1 in inode_init_always(). We can use the following program to trigger it: int main(int argc, char *argv[]) { int fd; fd = open(argv[1], O_TMPFILE, 0666); if (fd < 0) { perror("open "); return -1; } close(fd); return 0; } The oops message looks like this: kernel: kernel BUG at fs/ext3/namei.c:1992! kernel: invalid opcode: 0000 [#1] SMP kernel: Modules linked in: ext4 jbd2 crc16 cpufreq_ondemand ipv6 dm_mirror dm_region_hash dm_log dm_mod parport_pc parport serio_raw sg dcdbas pcspkr i2c_i801 ehci_pci ehci_hcd button acpi_cpufreq mperf e1000e ptp pps_core ttm drm_kms_helper drm hwmon i2c_algo_bit i2c_core ext3 jbd sd_mod ahci libahci libata scsi_mod uhci_hcd kernel: CPU: 0 PID: 2882 Comm: tst_tmpfile Not tainted 3.11.0-rc1+ #4 kernel: Hardware name: Dell Inc. OptiPlex 780 /0V4W66, BIOS A05 08/11/2010 kernel: task: ffff880112d30050 ti: ffff8801124d4000 task.ti: ffff8801124d4000 kernel: RIP: 0010:[<ffffffffa00db5ae>] [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3] kernel: RSP: 0018:ffff8801124d5cc8 EFLAGS: 00010202 kernel: RAX: 0000000000000000 RBX: ffff880111510128 RCX: ffff8801114683a0 kernel: RDX: 0000000000000000 RSI: ffff880111510128 RDI: ffff88010fcf65a8 kernel: RBP: ffff8801124d5d18 R08: 0080000000000000 R09: ffffffffa00d3b7f kernel: R10: ffff8801114683a0 R11: ffff8801032a2558 R12: 0000000000000000 kernel: R13: ffff88010fcf6800 R14: ffff8801032a2558 R15: ffff8801115100d8 kernel: FS: 00007f5d172b5700(0000) GS:ffff880117c00000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b kernel: CR2: 00007f5d16df15d0 CR3: 0000000110b1d000 CR4: 00000000000407f0 kernel: Stack: kernel: 000000000000000c ffff8801048a7dc8 ffff8801114685a8 ffffffffa00b80d7 kernel: ffff8801124d5e38 ffff8801032a2558 ffff88010ce24d68 0000000000000000 kernel: ffff88011146b300 ffff8801124d5d44 ffff8801124d5d78 ffffffffa00db7e1 kernel: Call Trace: kernel: [<ffffffffa00b80d7>] ? journal_start+0x8c/0xbd [jbd] kernel: [<ffffffffa00db7e1>] ext3_tmpfile+0xb2/0x13b [ext3] kernel: [<ffffffff821076f8>] path_openat+0x11f/0x5e7 kernel: [<ffffffff821c86b4>] ? list_del+0x11/0x30 kernel: [<ffffffff82065fa2>] ? __dequeue_entity+0x33/0x38 kernel: [<ffffffff82107cd5>] do_filp_open+0x3f/0x8d kernel: [<ffffffff82112532>] ? __alloc_fd+0x50/0x102 kernel: [<ffffffff820f9296>] do_sys_open+0x13b/0x1cd kernel: [<ffffffff820f935c>] SyS_open+0x1e/0x20 kernel: [<ffffffff82398c02>] system_call_fastpath+0x16/0x1b kernel: Code: 39 c7 0f 85 67 01 00 00 0f b7 03 25 00 f0 00 00 3d 00 40 00 00 74 18 3d 00 80 00 00 74 11 3d 00 a0 00 00 74 0a 83 7b 48 00 74 04 <0f> 0b eb fe 49 8b 85 50 03 00 00 4c 89 f6 48 c7 c7 c0 99 0e a0 kernel: RIP [<ffffffffa00db5ae>] ext3_orphan_add+0x6a/0x1eb [ext3] kernel: RSP <ffff8801124d5cc8> Here we couldn't call clear_nlink() directly because in d_tmpfile() we will call inode_dec_link_count() to decrease ->i_nlink. So this commit tries to call d_tmpfile() before ext4_orphan_add() to fix this problem. Signed-off-by: Zheng Liu <[email protected]> Signed-off-by: "Theodore Ts'o" <[email protected]> Cc: Jan Kara <[email protected]> Cc: Al Viro <[email protected]>

Commits 6a1c068 and 9356b53, respectively 'tty: Convert termios_mutex to termios_rwsem' and 'n_tty: Access termios values safely' introduced a circular lock dependency with console_lock and termios_rwsem. The lockdep report [1] shows that n_tty_write() will attempt to claim console_lock while holding the termios_rwsem, whereas tty_do_resize() may already hold the console_lock while claiming the termios_rwsem. Since n_tty_write() and tty_do_resize() do not contend over the same data -- the tty->winsize structure -- correct the lock dependency by introducing a new lock which specifically serializes access to tty->winsize only. [1] Lockdep report ====================================================== [ INFO: possible circular locking dependency detected ] 3.10.0-0+tip-xeon+lockdep #0+tip Not tainted ------------------------------------------------------- modprobe/277 is trying to acquire lock: (&tty->termios_rwsem){++++..}, at: [<ffffffff81452656>] tty_do_resize+0x36/0xe0 but task is already holding lock: ((fb_notifier_list).rwsem){.+.+.+}, at: [<ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 ((fb_notifier_list).rwsem){.+.+.+}: [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff8175b797>] down_read+0x47/0x5c [<ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0 [<ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20 [<ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20 [<ffffffff813d95b2>] register_framebuffer+0x1e2/0x320 [<ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper] [<ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau] [<ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau] [<ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm] [<ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau] [<ffffffff813b13db>] local_pci_probe+0x4b/0x80 [<ffffffff813b1701>] pci_device_probe+0x111/0x120 [<ffffffff814977eb>] driver_probe_device+0x8b/0x3a0 [<ffffffff81497bab>] __driver_attach+0xab/0xb0 [<ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0 [<ffffffff814971fe>] driver_attach+0x1e/0x20 [<ffffffff81496cc1>] bus_add_driver+0x111/0x290 [<ffffffff814982b7>] driver_register+0x77/0x170 [<ffffffff813b0454>] __pci_register_driver+0x64/0x70 [<ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm] [<ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau] [<ffffffff810002ea>] do_one_initcall+0xea/0x1a0 [<ffffffff810c54cb>] load_module+0x123b/0x1bf0 [<ffffffff810c5f57>] SyS_init_module+0xd7/0x120 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b -> #1 (console_lock){+.+.+.}: [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff810430a7>] console_lock+0x77/0x80 [<ffffffff8146b2a1>] con_flush_chars+0x31/0x50 [<ffffffff8145780c>] n_tty_write+0x1ec/0x4d0 [<ffffffff814541b9>] tty_write+0x159/0x2e0 [<ffffffff814543f5>] redirected_tty_write+0xb5/0xc0 [<ffffffff811ab9d5>] vfs_write+0xc5/0x1f0 [<ffffffff811abec5>] SyS_write+0x55/0xa0 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b -> #0 (&tty->termios_rwsem){++++..}: [<ffffffff810b65c3>] __lock_acquire+0x1c43/0x1d30 [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff8175b724>] down_write+0x44/0x70 [<ffffffff81452656>] tty_do_resize+0x36/0xe0 [<ffffffff8146c841>] vc_do_resize+0x3e1/0x4c0 [<ffffffff8146c99f>] vc_resize+0x1f/0x30 [<ffffffff813e4535>] fbcon_init+0x385/0x5a0 [<ffffffff8146a4bc>] visual_init+0xbc/0x120 [<ffffffff8146cd13>] do_bind_con_driver+0x163/0x320 [<ffffffff8146cfa1>] do_take_over_console+0x61/0x70 [<ffffffff813e2b93>] do_fbcon_takeover+0x63/0xc0 [<ffffffff813e67a5>] fbcon_event_notify+0x715/0x820 [<ffffffff81762f9d>] notifier_call_chain+0x5d/0x110 [<ffffffff8107aadc>] __blocking_notifier_call_chain+0x6c/0xc0 [<ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20 [<ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20 [<ffffffff813d95b2>] register_framebuffer+0x1e2/0x320 [<ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper] [<ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau] [<ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau] [<ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm] [<ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau] [<ffffffff813b13db>] local_pci_probe+0x4b/0x80 [<ffffffff813b1701>] pci_device_probe+0x111/0x120 [<ffffffff814977eb>] driver_probe_device+0x8b/0x3a0 [<ffffffff81497bab>] __driver_attach+0xab/0xb0 [<ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0 [<ffffffff814971fe>] driver_attach+0x1e/0x20 [<ffffffff81496cc1>] bus_add_driver+0x111/0x290 [<ffffffff814982b7>] driver_register+0x77/0x170 [<ffffffff813b0454>] __pci_register_driver+0x64/0x70 [<ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm] [<ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau] [<ffffffff810002ea>] do_one_initcall+0xea/0x1a0 [<ffffffff810c54cb>] load_module+0x123b/0x1bf0 [<ffffffff810c5f57>] SyS_init_module+0xd7/0x120 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b other info that might help us debug this: Chain exists of: &tty->termios_rwsem --> console_lock --> (fb_notifier_list).rwsem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((fb_notifier_list).rwsem); lock(console_lock); lock((fb_notifier_list).rwsem); lock(&tty->termios_rwsem); *** DEADLOCK *** 7 locks held by modprobe/277: #0: (&__lockdep_no_validate__){......}, at: [<ffffffff81497b5b>] __driver_attach+0x5b/0xb0 #1: (&__lockdep_no_validate__){......}, at: [<ffffffff81497b69>] __driver_attach+0x69/0xb0 #2: (drm_global_mutex){+.+.+.}, at: [<ffffffffa008a6dd>] drm_get_pci_dev+0xbd/0x2a0 [drm] #3: (registration_lock){+.+.+.}, at: [<ffffffff813d93f5>] register_framebuffer+0x25/0x320 #4: (&fb_info->lock){+.+.+.}, at: [<ffffffff813d8116>] lock_fb_info+0x26/0x60 #5: (console_lock){+.+.+.}, at: [<ffffffff813d95a4>] register_framebuffer+0x1d4/0x320 torvalds#6: ((fb_notifier_list).rwsem){.+.+.+}, at: [<ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0 stack backtrace: CPU: 0 PID: 277 Comm: modprobe Not tainted 3.10.0-0+tip-xeon+lockdep #0+tip Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012 ffffffff8213e5e0 ffff8802aa2fb298 ffffffff81755f19 ffff8802aa2fb2e8 ffffffff8174f506 ffff8802aa2fa000 ffff8802aa2fb378 ffff8802aa2ea8e8 ffff8802aa2ea910 ffff8802aa2ea8e8 0000000000000006 0000000000000007 Call Trace: [<ffffffff81755f19>] dump_stack+0x19/0x1b [<ffffffff8174f506>] print_circular_bug+0x1fb/0x20c [<ffffffff810b65c3>] __lock_acquire+0x1c43/0x1d30 [<ffffffff810b775e>] ? mark_held_locks+0xae/0x120 [<ffffffff810b78d5>] ? trace_hardirqs_on_caller+0x105/0x1d0 [<ffffffff810b6d62>] lock_acquire+0x92/0x1f0 [<ffffffff81452656>] ? tty_do_resize+0x36/0xe0 [<ffffffff8175b724>] down_write+0x44/0x70 [<ffffffff81452656>] ? tty_do_resize+0x36/0xe0 [<ffffffff81452656>] tty_do_resize+0x36/0xe0 [<ffffffff8146c841>] vc_do_resize+0x3e1/0x4c0 [<ffffffff8146c99f>] vc_resize+0x1f/0x30 [<ffffffff813e4535>] fbcon_init+0x385/0x5a0 [<ffffffff8146a4bc>] visual_init+0xbc/0x120 [<ffffffff8146cd13>] do_bind_con_driver+0x163/0x320 [<ffffffff8146cfa1>] do_take_over_console+0x61/0x70 [<ffffffff813e2b93>] do_fbcon_takeover+0x63/0xc0 [<ffffffff813e67a5>] fbcon_event_notify+0x715/0x820 [<ffffffff81762f9d>] notifier_call_chain+0x5d/0x110 [<ffffffff8107aadc>] __blocking_notifier_call_chain+0x6c/0xc0 [<ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20 [<ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20 [<ffffffff813d95b2>] register_framebuffer+0x1e2/0x320 [<ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper] [<ffffffff8173cbcb>] ? kmemleak_alloc+0x5b/0xc0 [<ffffffff81198874>] ? kmem_cache_alloc_trace+0x104/0x290 [<ffffffffa01035e1>] ? drm_fb_helper_single_add_all_connectors+0x81/0xf0 [drm_kms_helper] [<ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau] [<ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau] [<ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm] [<ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau] [<ffffffff8175f162>] ? _raw_spin_unlock_irqrestore+0x42/0x80 [<ffffffff813b13db>] local_pci_probe+0x4b/0x80 [<ffffffff813b1701>] pci_device_probe+0x111/0x120 [<ffffffff814977eb>] driver_probe_device+0x8b/0x3a0 [<ffffffff81497bab>] __driver_attach+0xab/0xb0 [<ffffffff81497b00>] ? driver_probe_device+0x3a0/0x3a0 [<ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0 [<ffffffff814971fe>] driver_attach+0x1e/0x20 [<ffffffff81496cc1>] bus_add_driver+0x111/0x290 [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffff814982b7>] driver_register+0x77/0x170 [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffff813b0454>] __pci_register_driver+0x64/0x70 [<ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm] [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffffa022a000>] ? 0xffffffffa0229fff [<ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau] [<ffffffff810002ea>] do_one_initcall+0xea/0x1a0 [<ffffffff810c54cb>] load_module+0x123b/0x1bf0 [<ffffffff81399a50>] ? ddebug_proc_open+0xb0/0xb0 [<ffffffff813855ae>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff810c5f57>] SyS_init_module+0xd7/0x120 [<ffffffff817677c2>] system_call_fastpath+0x16/0x1b Signed-off-by: Peter Hurley <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

Otherwise we end up dereferencing the already freed net->ipv6.mrt pointer which leads to a panic (from Srivatsa S. Bhat): BUG: unable to handle kernel paging request at ffff882018552020 IP: [<ffffffffa0366b02>] ip6mr_sk_done+0x32/0xb0 [ipv6] PGD 290a067 PUD 207ffe0067 PMD 207ff1d067 PTE 8000002018552060 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: ebtable_nat ebtables nfs fscache nf_conntrack_ipv4 nf_defrag_ipv4 ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables nfsd lockd nfs_acl exportfs auth_rpcgss autofs4 sunrpc 8021q garp bridge stp llc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter +ip6_tables ipv6 vfat fat vhost_net macvtap macvlan vhost tun kvm_intel kvm uinput iTCO_wdt iTCO_vendor_support cdc_ether usbnet mii microcode i2c_i801 i2c_core lpc_ich mfd_core shpchp ioatdma dca mlx4_core be2net wmi acpi_cpufreq mperf ext4 jbd2 mbcache dm_mirror dm_region_hash dm_log dm_mod CPU: 0 PID: 7 Comm: kworker/u33:0 Not tainted 3.11.0-rc1-ea45e-a #4 Hardware name: IBM -[8737R2A]-/00Y2738, BIOS -[B2E120RUS-1.20]- 11/30/2012 Workqueue: netns cleanup_net task: ffff8810393641c0 ti: ffff881039366000 task.ti: ffff881039366000 RIP: 0010:[<ffffffffa0366b02>] [<ffffffffa0366b02>] ip6mr_sk_done+0x32/0xb0 [ipv6] RSP: 0018:ffff881039367bd8 EFLAGS: 00010286 RAX: ffff881039367fd8 RBX: ffff882018552000 RCX: dead000000200200 RDX: 0000000000000000 RSI: ffff881039367b68 RDI: ffff881039367b68 RBP: ffff881039367bf8 R08: ffff881039367b68 R09: 2222222222222222 R10: 2222222222222222 R11: 2222222222222222 R12: ffff882015a7a040 R13: ffff882014eb89c0 R14: ffff8820289e2800 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88103fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff882018552020 CR3: 0000000001c0b000 CR4: 00000000000407f0 Stack: ffff881039367c18 ffff882014eb89c0 ffff882015e28c00 0000000000000000 ffff881039367c18 ffffffffa034d9d1 ffff8820289e2800 ffff882014eb89c0 ffff881039367c58 ffffffff815bdecb ffffffff815bddf2 ffff882014eb89c0 Call Trace: [<ffffffffa034d9d1>] rawv6_close+0x21/0x40 [ipv6] [<ffffffff815bdecb>] inet_release+0xfb/0x220 [<ffffffff815bddf2>] ? inet_release+0x22/0x220 [<ffffffffa032686f>] inet6_release+0x3f/0x50 [ipv6] [<ffffffff8151c1d9>] sock_release+0x29/0xa0 [<ffffffff81525520>] sk_release_kernel+0x30/0x70 [<ffffffffa034f14b>] icmpv6_sk_exit+0x3b/0x80 [ipv6] [<ffffffff8152fff9>] ops_exit_list+0x39/0x60 [<ffffffff815306fb>] cleanup_net+0xfb/0x1a0 [<ffffffff81075e3a>] process_one_work+0x1da/0x610 [<ffffffff81075dc9>] ? process_one_work+0x169/0x610 [<ffffffff81076390>] worker_thread+0x120/0x3a0 [<ffffffff81076270>] ? process_one_work+0x610/0x610 [<ffffffff8107da2e>] kthread+0xee/0x100 [<ffffffff8107d940>] ? __init_kthread_worker+0x70/0x70 [<ffffffff8162a99c>] ret_from_fork+0x7c/0xb0 [<ffffffff8107d940>] ? __init_kthread_worker+0x70/0x70 Code: 20 48 89 5d e8 4c 89 65 f0 4c 89 6d f8 66 66 66 66 90 4c 8b 67 30 49 89 fd e8 db 3c 1e e1 49 8b 9c 24 90 08 00 00 48 85 db 74 06 <4c> 39 6b 20 74 20 bb f3 ff ff ff e8 8e 3c 1e e1 89 d8 4c 8b 65 RIP [<ffffffffa0366b02>] ip6mr_sk_done+0x32/0xb0 [ipv6] RSP <ffff881039367bd8> CR2: ffff882018552020 Reported-by: Srivatsa S. Bhat <[email protected]> Tested-by: Srivatsa S. Bhat <[email protected]> Signed-off-by: Hannes Frederic Sowa <[email protected]> Signed-off-by: David S. Miller <[email protected]>

We used to keep the port's char device structs and the /sys entries around till the last reference to the port was dropped. This is actually unnecessary, and resulted in buggy behaviour: 1. Open port in guest 2. Hot-unplug port 3. Hot-plug a port with the same 'name' property as the unplugged one This resulted in hot-plug being unsuccessful, as a port with the same name already exists (even though it was unplugged). This behaviour resulted in a warning message like this one: -------------------8<--------------------------------------- WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xc9/0x130() (Not tainted) Hardware name: KVM sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:04.0/virtio0/virtio-ports/vport0p1' Call Trace: [<ffffffff8106b607>] ? warn_slowpath_common+0x87/0xc0 [<ffffffff8106b6f6>] ? warn_slowpath_fmt+0x46/0x50 [<ffffffff811f2319>] ? sysfs_add_one+0xc9/0x130 [<ffffffff811f23e8>] ? create_dir+0x68/0xb0 [<ffffffff811f2469>] ? sysfs_create_dir+0x39/0x50 [<ffffffff81273129>] ? kobject_add_internal+0xb9/0x260 [<ffffffff812733d8>] ? kobject_add_varg+0x38/0x60 [<ffffffff812734b4>] ? kobject_add+0x44/0x70 [<ffffffff81349de4>] ? get_device_parent+0xf4/0x1d0 [<ffffffff8134b389>] ? device_add+0xc9/0x650 -------------------8<--------------------------------------- Instead of relying on guest applications to release all references to the ports, we should go ahead and unregister the port from all the core layers. Any open/read calls on the port will then just return errors, and an unplug/plug operation on the host will succeed as expected. This also caused buggy behaviour in case of the device removal (not just a port): when the device was removed (which means all ports on that device are removed automatically as well), the ports with active users would clean up only when the last references were dropped -- and it would be too late then to be referencing char device pointers, resulting in oopses: -------------------8<--------------------------------------- PID: 6162 TASK: ffff8801147ad500 CPU: 0 COMMAND: "cat" #0 [ffff88011b9d5a90] machine_kexec at ffffffff8103232b #1 [ffff88011b9d5af0] crash_kexec at ffffffff810b9322 #2 [ffff88011b9d5bc0] oops_end at ffffffff814f4a50 #3 [ffff88011b9d5bf0] die at ffffffff8100f26b #4 [ffff88011b9d5c20] do_general_protection at ffffffff814f45e2 #5 [ffff88011b9d5c50] general_protection at ffffffff814f3db5 [exception RIP: strlen+2] RIP: ffffffff81272ae2 RSP: ffff88011b9d5d00 RFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff880118901c18 RCX: 0000000000000000 RDX: ffff88011799982c RSI: 00000000000000d0 RDI: 3a303030302f3030 RBP: ffff88011b9d5d38 R8: 0000000000000006 R9: ffffffffa0134500 R10: 0000000000001000 R11: 0000000000001000 R12: ffff880117a1cc10 R13: 00000000000000d0 R14: 0000000000000017 R15: ffffffff81aff700 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 torvalds#6 [ffff88011b9d5d00] kobject_get_path at ffffffff8126dc5d torvalds#7 [ffff88011b9d5d40] kobject_uevent_env at ffffffff8126e551 torvalds#8 [ffff88011b9d5dd0] kobject_uevent at ffffffff8126e9eb torvalds#9 [ffff88011b9d5de0] device_del at ffffffff813440c7 -------------------8<--------------------------------------- So clean up when we have all the context, and all that's left to do when the references to the port have dropped is to free up the port struct itself. CC: <[email protected]> Reported-by: chayang <[email protected]> Reported-by: YOGANANTH SUBRAMANIAN <[email protected]> Reported-by: FuXiangChun <[email protected]> Reported-by: Qunfang Zhang <[email protected]> Reported-by: Sibiao Luo <[email protected]> Signed-off-by: Amit Shah <[email protected]> Signed-off-by: Rusty Russell <[email protected]>

Otherwise we get flooded by the kernel warning us that we are doing long sequences of IO without serialisation. For example, WARNING: CPU: 0 PID: 11136 at drivers/gpu/drm/i915/intel_sideband.c:40 vlv_sideband_rw+0x48/0x1ef() Modules linked in: CPU: 0 PID: 11136 Comm: kworker/u2:0 Tainted: G W 3.11.0-rc2+ #4 Call Trace: [<c2028564>] ? warn_slowpath_common+0x63/0x78 [<c227ad43>] ? vlv_sideband_rw+0x48/0x1ef [<c20285dd>] ? warn_slowpath_null+0xf/0x13 [<c227ad43>] ? vlv_sideband_rw+0x48/0x1ef [<c227b060>] ? vlv_dpio_write+0x1c/0x21 [<c2262b3b>] ? intel_dp_set_signal_levels+0x24a/0x385 [<c2264909>] ? intel_dp_complete_link_train+0x25/0x1d1 [<c2264c55>] ? intel_dp_check_link_status+0xf7/0x106 [<c2238ced>] ? i915_hotplug_work_func+0x17b/0x221 [<c203a204>] ? process_one_work+0x12e/0x210 [<c203a5e4>] ? worker_thread+0x116/0x1ad [<c203a4ce>] ? rescuer_thread+0x1cb/0x1cb [<c203d8f5>] ? kthread+0x67/0x6c [<c2457ebb>] ? ret_from_kernel_thread+0x1b/0x30 [<c203d88e>] ? init_completion+0x18/0x18 v2: Retire the locking in vlv_crtc_enable() and do it close to the meat. Signed-off-by: Chris Wilson <[email protected]> Reviewed-by: Jani Nikula <[email protected]> [danvet: Squash in a s/mutex_lock/mutex_unlock/ fixup spotted by the 0 day kernel build/coccinelle and reported by Dan Carpenter.] Signed-off-by: Daniel Vetter <[email protected]>

Since commit 29a241c (ACPICA: Add argument typechecking for all predefined ACPI names), _DSM parameters are validated which trigger the following warning: ACPI Warning: \_SB_.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Integer], ACPI requires [Package] (20130517/nsarguments-95) ACPI Warning: \_SB_.PCI0.GFX0._DSM: Argument #4 type mismatch - Found [Integer], ACPI requires [Package] (20130517/nsarguments-95) ACPI Warning: \_SB_.PCI0.P0P2.PEGP._DSM: Argument #4 type mismatch - Found [Integer], ACPI requires [Package] (20130517/nsarguments-95) ACPI Warning: \_SB_.PCI0.P0P2.PEGP._DSM: Argument #4 type mismatch - Found [Integer], ACPI requires [Package] (20130517/nsarguments-95) As the Intel _DSM method seems to ignore this parameter, let's comply to the ACPI spec and use a Package instead. Signed-off-by: Peter Wu <[email protected]> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=32602 Signed-off-by: Daniel Vetter <[email protected]>

We met lockdep warning when enable and disable the bearer for commands such as: tipc-config -netid=1234 -addr=1.1.3 -be=eth:eth0 tipc-config -netid=1234 -addr=1.1.3 -bd=eth:eth0 --------------------------------------------------- [ 327.693595] ====================================================== [ 327.693994] [ INFO: possible circular locking dependency detected ] [ 327.694519] 3.11.0-rc3-wwd-default #4 Tainted: G O [ 327.694882] ------------------------------------------------------- [ 327.695385] tipc-config/5825 is trying to acquire lock: [ 327.695754] (((timer))#2){+.-...}, at: [<ffffffff8105be80>] del_timer_sync+0x0/0xd0 [ 327.696018] [ 327.696018] but task is already holding lock: [ 327.696018] (&(&b_ptr->lock)->rlock){+.-...}, at: [<ffffffffa02be58d>] bearer_disable+ 0xdd/0x120 [tipc] [ 327.696018] [ 327.696018] which lock already depends on the new lock. [ 327.696018] [ 327.696018] [ 327.696018] the existing dependency chain (in reverse order) is: [ 327.696018] [ 327.696018] -> #1 (&(&b_ptr->lock)->rlock){+.-...}: [ 327.696018] [<ffffffff810b3b4d>] validate_chain+0x6dd/0x870 [ 327.696018] [<ffffffff810b40bb>] __lock_acquire+0x3db/0x670 [ 327.696018] [<ffffffff810b4453>] lock_acquire+0x103/0x130 [ 327.696018] [<ffffffff814d65b1>] _raw_spin_lock_bh+0x41/0x80 [ 327.696018] [<ffffffffa02c5d48>] disc_timeout+0x18/0xd0 [tipc] [ 327.696018] [<ffffffff8105b92a>] call_timer_fn+0xda/0x1e0 [ 327.696018] [<ffffffff8105bcd7>] run_timer_softirq+0x2a7/0x2d0 [ 327.696018] [<ffffffff8105379a>] __do_softirq+0x16a/0x2e0 [ 327.696018] [<ffffffff81053a35>] irq_exit+0xd5/0xe0 [ 327.696018] [<ffffffff81033005>] smp_apic_timer_interrupt+0x45/0x60 [ 327.696018] [<ffffffff814df4af>] apic_timer_interrupt+0x6f/0x80 [ 327.696018] [<ffffffff8100b70e>] arch_cpu_idle+0x1e/0x30 [ 327.696018] [<ffffffff810a039d>] cpu_idle_loop+0x1fd/0x280 [ 327.696018] [<ffffffff810a043e>] cpu_startup_entry+0x1e/0x20 [ 327.696018] [<ffffffff81031589>] start_secondary+0x89/0x90 [ 327.696018] [ 327.696018] -> #0 (((timer))#2){+.-...}: [ 327.696018] [<ffffffff810b33fe>] check_prev_add+0x43e/0x4b0 [ 327.696018] [<ffffffff810b3b4d>] validate_chain+0x6dd/0x870 [ 327.696018] [<ffffffff810b40bb>] __lock_acquire+0x3db/0x670 [ 327.696018] [<ffffffff810b4453>] lock_acquire+0x103/0x130 [ 327.696018] [<ffffffff8105bebd>] del_timer_sync+0x3d/0xd0 [ 327.696018] [<ffffffffa02c5855>] tipc_disc_delete+0x15/0x30 [tipc] [ 327.696018] [<ffffffffa02be59f>] bearer_disable+0xef/0x120 [tipc] [ 327.696018] [<ffffffffa02be74f>] tipc_disable_bearer+0x2f/0x60 [tipc] [ 327.696018] [<ffffffffa02bfb32>] tipc_cfg_do_cmd+0x2e2/0x550 [tipc] [ 327.696018] [<ffffffffa02c8c79>] handle_cmd+0x49/0xe0 [tipc] [ 327.696018] [<ffffffff8143e898>] genl_family_rcv_msg+0x268/0x340 [ 327.696018] [<ffffffff8143ed30>] genl_rcv_msg+0x70/0xd0 [ 327.696018] [<ffffffff8143d4c9>] netlink_rcv_skb+0x89/0xb0 [ 327.696018] [<ffffffff8143e617>] genl_rcv+0x27/0x40 [ 327.696018] [<ffffffff8143d21e>] netlink_unicast+0x15e/0x1b0 [ 327.696018] [<ffffffff8143ddcf>] netlink_sendmsg+0x22f/0x400 [ 327.696018] [<ffffffff813f7836>] __sock_sendmsg+0x66/0x80 [ 327.696018] [<ffffffff813f7957>] sock_aio_write+0x107/0x120 [ 327.696018] [<ffffffff8117f76d>] do_sync_write+0x7d/0xc0 [ 327.696018] [<ffffffff8117fc56>] vfs_write+0x186/0x190 [ 327.696018] [<ffffffff811803e0>] SyS_write+0x60/0xb0 [ 327.696018] [<ffffffff814de852>] system_call_fastpath+0x16/0x1b [ 327.696018] [ 327.696018] other info that might help us debug this: [ 327.696018] [ 327.696018] Possible unsafe locking scenario: [ 327.696018] [ 327.696018] CPU0 CPU1 [ 327.696018] ---- ---- [ 327.696018] lock(&(&b_ptr->lock)->rlock); [ 327.696018] lock(((timer))#2); [ 327.696018] lock(&(&b_ptr->lock)->rlock); [ 327.696018] lock(((timer))#2); [ 327.696018] [ 327.696018] *** DEADLOCK *** [ 327.696018] [ 327.696018] 5 locks held by tipc-config/5825: [ 327.696018] #0: (cb_lock){++++++}, at: [<ffffffff8143e608>] genl_rcv+0x18/0x40 [ 327.696018] #1: (genl_mutex){+.+.+.}, at: [<ffffffff8143ed66>] genl_rcv_msg+0xa6/0xd0 [ 327.696018] #2: (config_mutex){+.+.+.}, at: [<ffffffffa02bf889>] tipc_cfg_do_cmd+0x39/ 0x550 [tipc] [ 327.696018] #3: (tipc_net_lock){++.-..}, at: [<ffffffffa02be738>] tipc_disable_bearer+ 0x18/0x60 [tipc] [ 327.696018] #4: (&(&b_ptr->lock)->rlock){+.-...}, at: [<ffffffffa02be58d>] bearer_disable+0xdd/0x120 [tipc] [ 327.696018] [ 327.696018] stack backtrace: [ 327.696018] CPU: 2 PID: 5825 Comm: tipc-config Tainted: G O 3.11.0-rc3-wwd- default #4 [ 327.696018] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 327.696018] 00000000ffffffff ffff880037fa77a8 ffffffff814d03dd 0000000000000000 [ 327.696018] ffff880037fa7808 ffff880037fa77e8 ffffffff810b1c4f 0000000037fa77e8 [ 327.696018] ffff880037fa7808 ffff880037e4db40 0000000000000000 ffff880037e4e318 [ 327.696018] Call Trace: [ 327.696018] [<ffffffff814d03dd>] dump_stack+0x4d/0xa0 [ 327.696018] [<ffffffff810b1c4f>] print_circular_bug+0x10f/0x120 [ 327.696018] [<ffffffff810b33fe>] check_prev_add+0x43e/0x4b0 [ 327.696018] [<ffffffff810b3b4d>] validate_chain+0x6dd/0x870 [ 327.696018] [<ffffffff81087a28>] ? sched_clock_cpu+0xd8/0x110 [ 327.696018] [<ffffffff810b40bb>] __lock_acquire+0x3db/0x670 [ 327.696018] [<ffffffff810b4453>] lock_acquire+0x103/0x130 [ 327.696018] [<ffffffff8105be80>] ? try_to_del_timer_sync+0x70/0x70 [ 327.696018] [<ffffffff8105bebd>] del_timer_sync+0x3d/0xd0 [ 327.696018] [<ffffffff8105be80>] ? try_to_del_timer_sync+0x70/0x70 [ 327.696018] [<ffffffffa02c5855>] tipc_disc_delete+0x15/0x30 [tipc] [ 327.696018] [<ffffffffa02be59f>] bearer_disable+0xef/0x120 [tipc] [ 327.696018] [<ffffffffa02be74f>] tipc_disable_bearer+0x2f/0x60 [tipc] [ 327.696018] [<ffffffffa02bfb32>] tipc_cfg_do_cmd+0x2e2/0x550 [tipc] [ 327.696018] [<ffffffff81218783>] ? security_capable+0x13/0x20 [ 327.696018] [<ffffffffa02c8c79>] handle_cmd+0x49/0xe0 [tipc] [ 327.696018] [<ffffffff8143e898>] genl_family_rcv_msg+0x268/0x340 [ 327.696018] [<ffffffff8143ed30>] genl_rcv_msg+0x70/0xd0 [ 327.696018] [<ffffffff8143ecc0>] ? genl_lock+0x20/0x20 [ 327.696018] [<ffffffff8143d4c9>] netlink_rcv_skb+0x89/0xb0 [ 327.696018] [<ffffffff8143e608>] ? genl_rcv+0x18/0x40 [ 327.696018] [<ffffffff8143e617>] genl_rcv+0x27/0x40 [ 327.696018] [<ffffffff8143d21e>] netlink_unicast+0x15e/0x1b0 [ 327.696018] [<ffffffff81289d7c>] ? memcpy_fromiovec+0x6c/0x90 [ 327.696018] [<ffffffff8143ddcf>] netlink_sendmsg+0x22f/0x400 [ 327.696018] [<ffffffff813f7836>] __sock_sendmsg+0x66/0x80 [ 327.696018] [<ffffffff813f7957>] sock_aio_write+0x107/0x120 [ 327.696018] [<ffffffff813fe29c>] ? release_sock+0x8c/0xa0 [ 327.696018] [<ffffffff8117f76d>] do_sync_write+0x7d/0xc0 [ 327.696018] [<ffffffff8117fa24>] ? rw_verify_area+0x54/0x100 [ 327.696018] [<ffffffff8117fc56>] vfs_write+0x186/0x190 [ 327.696018] [<ffffffff811803e0>] SyS_write+0x60/0xb0 [ 327.696018] [<ffffffff814de852>] system_call_fastpath+0x16/0x1b ----------------------------------------------------------------------- The problem is that the tipc_link_delete() will cancel the timer disc_timeout() when the b_ptr->lock is hold, but the disc_timeout() still call b_ptr->lock to finish the work, so the dead lock occurs. We should unlock the b_ptr->lock when del the disc_timeout(). Remove link_timeout() still met the same problem, the patch: http://article.gmane.org/gmane.network.tipc.general/4380 fix the problem, so no need to send patch for fix link_timeout() deadlock warming. Signed-off-by: Wang Weidong <[email protected]> Signed-off-by: Ding Tianhong <[email protected]> Acked-by: Ying Xue <[email protected]> Signed-off-by: David S. Miller <[email protected]>

Fix a NULL pointer deference while removing an empty directory, which was introduced by commit 3704412 ("[readdir] convert ocfs2"). BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<(null)>] (null) PGD 6da85067 PUD 6da89067 PMD 0 Oops: 0010 [#1] SMP CPU: 0 PID: 6564 Comm: rmdir Tainted: G O 3.11.0-rc1 #4 RIP: 0010:[<0000000000000000>] [< (null)>] (null) Call Trace: ocfs2_dir_foreach+0x49/0x50 [ocfs2] ocfs2_empty_dir+0x12c/0x3e0 [ocfs2] ocfs2_unlink+0x56e/0xc10 [ocfs2] vfs_rmdir+0xd5/0x140 do_rmdir+0x1cb/0x1e0 SyS_rmdir+0x16/0x20 system_call_fastpath+0x16/0x1b Code: Bad RIP value. RIP [< (null)>] (null) RSP <ffff88006daddc10> CR2: 0000000000000000 [[email protected]: fix pointer math] Signed-off-by: Jie Liu <[email protected]> Reported-by: David Weber <[email protected]> Cc: Al Viro <[email protected]> Cc: Joel Becker <[email protected]> Cc: Mark Fasheh <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

ACPI 5.0 specification requires the fourth parameter to the _DSM (Device Specific Method) to be of type package instead of integer. Failing to do that we get following warning on the console: ACPI Warning: \_SB_.PCI0.I2C1.TPL0._DSM: Argument #4 type mismatch - Found [Integer], ACPI requires [Package] (20130517/nsarguments-95) Fix this by passing an empty package to the _DSM method. The HID over I2C specification doesn't require any specific values to be passed with this parameter. Signed-off-by: Mika Westerberg <[email protected]> Reviewed-by: Benjamin Tissoires <[email protected]> Signed-off-by: Jiri Kosina <[email protected]>

When booting secondary CPUs, announce_cpu() is called to show which cpu has been brought up. For example: [ 0.402751] smpboot: Booting Node 0, Processors #1 #2 #3 #4 #5 OK [ 0.525667] smpboot: Booting Node 1, Processors torvalds#6 torvalds#7 torvalds#8 torvalds#9 torvalds#10 torvalds#11 OK [ 0.755592] smpboot: Booting Node 0, Processors torvalds#12 torvalds#13 torvalds#14 torvalds#15 torvalds#16 torvalds#17 OK [ 0.890495] smpboot: Booting Node 1, Processors torvalds#18 torvalds#19 torvalds#20 torvalds#21 torvalds#22 torvalds#23 But the last "OK" is lost, because 'nr_cpu_ids-1' represents the maximum possible cpu id. It should use the maximum present cpu id in case not all CPUs booted up. Signed-off-by: Libin <[email protected]> Cc: <[email protected]> Cc: <[email protected]> Cc: <[email protected]> Cc: <[email protected]> Link: http://lkml.kernel.org/r/[email protected] [ tweaked the changelog, removed unnecessary line break, tweaked the format to align the fields vertically. ] Signed-off-by: Ingo Molnar <[email protected]>

Not all I/O ASIC versions have the free-running counter implemented, an early revision used in the 5000/1xx models aka 3MIN and 4MIN did not have it. Therefore we cannot unconditionally use it as a clock source. Fortunately if not implemented its register slot has a fixed value so it is enough if we check for the value at the end of the calibration period being the same as at the beginning. This also means we need to look for another high-precision clock source on the systems affected. The 5000/1xx can have an R4000SC processor installed where the CP0 Count register can be used as a clock source. Unfortunately all the R4k DECstations suffer from the missed timer interrupt on CP0 Count reads erratum, so we cannot use the CP0 timer as a clock source and a clock event both at a time. However we never need an R4k clock event device because all DECstations have a DS1287A RTC chip whose periodic interrupt can be used as a clock source. This gives us the following four configuration possibilities for I/O ASIC DECstations: 1. No I/O ASIC counter and no CP0 timer, e.g. R3k 5000/1xx (3MIN). 2. No I/O ASIC counter but the CP0 timer, i.e. R4k 5000/150 (4MIN). 3. The I/O ASIC counter but no CP0 timer, e.g. R3k 5000/240 (3MAX+). 4. The I/O ASIC counter and the CP0 timer, e.g. R4k 5000/260 (4MAX+). For #1 and #2 this change stops the I/O ASIC free-running counter from being installed as a clock source of a 0Hz frequency. For #2 it also arranges for the CP0 timer to be used as a clock source rather than a clock event device, because having an accurate wall clock is more important than a high-precision interval timer. For #3 there is no change. For #4 the change makes the I/O ASIC free-running counter installed as a clock source so that the CP0 timer can be used as a clock event device. Unfortunately the use of the CP0 timer as a clock event device relies on a succesful completion of c0_compare_interrupt. That never happens, because while waiting for a CP0 Compare interrupt to happen the function spins in a loop reading the CP0 Count register. This makes the CP0 Count erratum trigger reliably causing the interrupt waited for to be lost in all cases. As a result #4 resorts to using the CP0 timer as a clock source as well, just as #2. However we want to keep this separate arrangement in case (hope) c0_compare_interrupt is eventually rewritten such that it avoids the erratum. Signed-off-by: Maciej W. Rozycki <[email protected]> Cc: [email protected] Patchwork: https://patchwork.linux-mips.org/patch/5825/ Signed-off-by: Ralf Baechle <[email protected]>

When parsing lines from objdump a line containing source code starting with a numeric label is mistaken for a line of disassembly starting with a memory address. Current validation fails to recognise that the "memory address" is out of range and calculates an invalid offset which later causes this segfault: Program received signal SIGSEGV, Segmentation fault. 0x0000000000457315 in disasm__calc_percent (notes=0xc98970, evidx=0, offset=143705, end=2127526177, path=0x7fffffffbf50) at util/annotate.c:631 631 hits += h->addr[offset++]; (gdb) bt #0 0x0000000000457315 in disasm__calc_percent (notes=0xc98970, evidx=0, offset=143705, end=2127526177, path=0x7fffffffbf50) at util/annotate.c:631 #1 0x00000000004d65e3 in annotate_browser__calc_percent (browser=0x7fffffffd130, evsel=0xa01da0) at ui/browsers/annotate.c:364 #2 0x00000000004d7433 in annotate_browser__run (browser=0x7fffffffd130, evsel=0xa01da0, hbt=0x0) at ui/browsers/annotate.c:672 #3 0x00000000004d80c9 in symbol__tui_annotate (sym=0xc989a0, map=0xa02660, evsel=0xa01da0, hbt=0x0) at ui/browsers/annotate.c:962 #4 0x00000000004d7aa0 in hist_entry__tui_annotate (he=0xdf73f0, evsel=0xa01da0, hbt=0x0) at ui/browsers/annotate.c:823 #5 0x00000000004dd648 in perf_evsel__hists_browse (evsel=0xa01da0, nr_events=1, helpline= 0x58b768 "For a higher level overview, try: perf report --sort comm,dso", ev_name=0xa02cd0 "cycles", left_exits=false, hbt= 0x0, min_pcnt=0, env=0xa011e0) at ui/browsers/hists.c:1659 torvalds#6 0x00000000004de372 in perf_evlist__tui_browse_hists (evlist=0xa01520, help= 0x58b768 "For a higher level overview, try: perf report --sort comm,dso", hbt=0x0, min_pcnt=0, env=0xa011e0) at ui/browsers/hists.c:1950 torvalds#7 0x000000000042cf6b in __cmd_report (rep=0x7fffffffd6c0) at builtin-report.c:581 torvalds#8 0x000000000042e25d in cmd_report (argc=0, argv=0x7fffffffe4b0, prefix=0x0) at builtin-report.c:965 torvalds#9 0x000000000041a0e1 in run_builtin (p=0x801548, argc=1, argv=0x7fffffffe4b0) at perf.c:319 torvalds#10 0x000000000041a319 in handle_internal_command (argc=1, argv=0x7fffffffe4b0) at perf.c:376 torvalds#11 0x000000000041a465 in run_argv (argcp=0x7fffffffe38c, argv=0x7fffffffe380) at perf.c:420 torvalds#12 0x000000000041a707 in main (argc=1, argv=0x7fffffffe4b0) at perf.c:521 After the fix is applied the symbol can be annotated showing the problematic line "1: rep" copy_user_generic_string /usr/lib/debug/lib/modules/3.9.10-100.fc17.x86_64/vmlinux */ ENTRY(copy_user_generic_string) CFI_STARTPROC ASM_STAC andl %edx,%edx and %edx,%edx jz 4f je 37 cmpl $8,%edx cmp $0x8,%edx jb 2f /* less than 8 bytes, go to byte copy loop */ jb 33 ALIGN_DESTINATION mov %edi,%ecx and $0x7,%ecx je 28 sub $0x8,%ecx neg %ecx sub %ecx,%edx 1a: mov (%rsi),%al mov %al,(%rdi) inc %rsi inc %rdi dec %ecx jne 1a movl %edx,%ecx 28: mov %edx,%ecx shrl $3,%ecx shr $0x3,%ecx andl $7,%edx and $0x7,%edx 1: rep 100.00 rep movsq %ds:(%rsi),%es:(%rdi) movsq 2: movl %edx,%ecx 33: mov %edx,%ecx 3: rep rep movsb %ds:(%rsi),%es:(%rdi) movsb 4: xorl %eax,%eax 37: xor %eax,%eax data32 xchg %ax,%ax ASM_CLAC ret retq Signed-off-by: Adrian Hunter <[email protected]> Cc: David Ahern <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Stephane Eranian <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

…CIe cards The band selection and PE control code for the RT3593 chipsets only handles USB based devices currently. Due to this limitation RT3593 based PCIe cards are not working correctly. On PCIe cards band selection is controlled via GPIO torvalds#8 which is identical to the USB devices. The LNA PE control is slightly different, all LNA PEs are controlled by GPIO #4. Update the code to configure the GPIO_CTRL register correctly on PCIe devices. Cc: Steven Liu <[email protected]> Cc: JasonYS Cheng <[email protected]> Signed-off-by: Gabor Juhos <[email protected]> Signed-off-by: John W. Linville <[email protected]>

As the new x86 CPU bootup printout format code maintainer, I am taking immediate action to improve and clean (and thus indulge my OCD) the reporting of the cores when coming up online. Fix padding to a right-hand alignment, cleanup code and bind reporting width to the max number of supported CPUs on the system, like this: [ 0.074509] smpboot: Booting Node 0, Processors: #1 #2 #3 #4 #5 torvalds#6 torvalds#7 OK [ 0.644008] smpboot: Booting Node 1, Processors: torvalds#8 torvalds#9 torvalds#10 torvalds#11 torvalds#12 torvalds#13 torvalds#14 torvalds#15 OK [ 1.245006] smpboot: Booting Node 2, Processors: torvalds#16 torvalds#17 torvalds#18 torvalds#19 torvalds#20 torvalds#21 torvalds#22 torvalds#23 OK [ 1.864005] smpboot: Booting Node 3, Processors: torvalds#24 torvalds#25 torvalds#26 torvalds#27 torvalds#28 torvalds#29 torvalds#30 torvalds#31 OK [ 2.489005] smpboot: Booting Node 4, Processors: torvalds#32 torvalds#33 torvalds#34 torvalds#35 torvalds#36 torvalds#37 torvalds#38 torvalds#39 OK [ 3.093005] smpboot: Booting Node 5, Processors: torvalds#40 torvalds#41 torvalds#42 torvalds#43 torvalds#44 torvalds#45 torvalds#46 torvalds#47 OK [ 3.698005] smpboot: Booting Node 6, Processors: torvalds#48 torvalds#49 torvalds#50 torvalds#51 #52 #53 torvalds#54 torvalds#55 OK [ 4.304005] smpboot: Booting Node 7, Processors: torvalds#56 torvalds#57 #58 torvalds#59 torvalds#60 torvalds#61 torvalds#62 torvalds#63 OK [ 4.961413] Brought up 64 CPUs and this: [ 0.072367] smpboot: Booting Node 0, Processors: #1 #2 #3 #4 #5 torvalds#6 torvalds#7 OK [ 0.686329] Brought up 8 CPUs Signed-off-by: Borislav Petkov <[email protected]> Cc: Libin <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>

Michael Semon reported that xfs/299 generated this lockdep warning: ============================================= [ INFO: possible recursive locking detected ] 3.12.0-rc2+ #2 Not tainted --------------------------------------------- touch/21072 is trying to acquire lock: (&xfs_dquot_other_class){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 but task is already holding lock: (&xfs_dquot_other_class){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&xfs_dquot_other_class); lock(&xfs_dquot_other_class); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by touch/21072: #0: (sb_writers#10){++++.+}, at: [<c11185b6>] mnt_want_write+0x1e/0x3e #1: (&type->i_mutex_dir_key#4){+.+.+.}, at: [<c11078ee>] do_last+0x245/0xe40 #2: (sb_internal#2){++++.+}, at: [<c122c9e0>] xfs_trans_alloc+0x1f/0x35 #3: (&(&ip->i_lock)->mr_lock/1){+.+...}, at: [<c126cd1b>] xfs_ilock+0x100/0x1f1 #4: (&(&ip->i_lock)->mr_lock){++++-.}, at: [<c126cf52>] xfs_ilock_nowait+0x105/0x22f #5: (&dqp->q_qlock){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 torvalds#6: (&xfs_dquot_other_class){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 The lockdep annotation for dquot lock nesting only understands locking for user and "other" dquots, not user, group and quota dquots. Fix the annotations to match the locking heirarchy we now have. Reported-by: Michael L. Semon <[email protected]> Signed-off-by: Dave Chinner <[email protected]> Reviewed-by: Ben Myers <[email protected]> Signed-off-by: Ben Myers <[email protected]>

Turn it into (for example): [ 0.073380] x86: Booting SMP configuration: [ 0.074005] .... node #0, CPUs: #1 #2 #3 #4 #5 torvalds#6 torvalds#7 [ 0.603005] .... node #1, CPUs: torvalds#8 torvalds#9 torvalds#10 torvalds#11 torvalds#12 torvalds#13 torvalds#14 torvalds#15 [ 1.200005] .... node #2, CPUs: torvalds#16 torvalds#17 torvalds#18 torvalds#19 torvalds#20 torvalds#21 torvalds#22 torvalds#23 [ 1.796005] .... node #3, CPUs: torvalds#24 torvalds#25 torvalds#26 torvalds#27 torvalds#28 torvalds#29 torvalds#30 torvalds#31 [ 2.393005] .... node #4, CPUs: torvalds#32 torvalds#33 torvalds#34 torvalds#35 torvalds#36 torvalds#37 torvalds#38 torvalds#39 [ 2.996005] .... node #5, CPUs: torvalds#40 torvalds#41 torvalds#42 torvalds#43 torvalds#44 torvalds#45 torvalds#46 torvalds#47 [ 3.600005] .... node torvalds#6, CPUs: torvalds#48 torvalds#49 torvalds#50 torvalds#51 #52 #53 torvalds#54 torvalds#55 [ 4.202005] .... node torvalds#7, CPUs: torvalds#56 torvalds#57 #58 torvalds#59 torvalds#60 torvalds#61 torvalds#62 torvalds#63 [ 4.811005] .... node torvalds#8, CPUs: torvalds#64 torvalds#65 torvalds#66 torvalds#67 torvalds#68 torvalds#69 #70 torvalds#71 [ 5.421006] .... node torvalds#9, CPUs: torvalds#72 torvalds#73 torvalds#74 torvalds#75 torvalds#76 torvalds#77 torvalds#78 torvalds#79 [ 6.032005] .... node torvalds#10, CPUs: torvalds#80 torvalds#81 torvalds#82 torvalds#83 torvalds#84 torvalds#85 torvalds#86 torvalds#87 [ 6.648006] .... node torvalds#11, CPUs: torvalds#88 torvalds#89 torvalds#90 torvalds#91 torvalds#92 torvalds#93 torvalds#94 torvalds#95 [ 7.262005] .... node torvalds#12, CPUs: torvalds#96 torvalds#97 torvalds#98 torvalds#99 torvalds#100 torvalds#101 torvalds#102 torvalds#103 [ 7.865005] .... node torvalds#13, CPUs: torvalds#104 torvalds#105 torvalds#106 torvalds#107 torvalds#108 torvalds#109 torvalds#110 torvalds#111 [ 8.466005] .... node torvalds#14, CPUs: torvalds#112 torvalds#113 torvalds#114 torvalds#115 torvalds#116 torvalds#117 torvalds#118 torvalds#119 [ 9.073006] .... node torvalds#15, CPUs: torvalds#120 torvalds#121 torvalds#122 torvalds#123 torvalds#124 torvalds#125 torvalds#126 torvalds#127 [ 9.679901] x86: Booted up 16 nodes, 128 CPUs and drop useless elements. Change num_digits() to hpa's division-avoiding, cell-phone-typed version which he went at great lengths and pains to submit on a Saturday evening. Signed-off-by: Borislav Petkov <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Linus Torvalds <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>

Michael Semon reported that xfs/299 generated this lockdep warning: ============================================= [ INFO: possible recursive locking detected ] 3.12.0-rc2+ #2 Not tainted --------------------------------------------- touch/21072 is trying to acquire lock: (&xfs_dquot_other_class){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 but task is already holding lock: (&xfs_dquot_other_class){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&xfs_dquot_other_class); lock(&xfs_dquot_other_class); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by touch/21072: #0: (sb_writers#10){++++.+}, at: [<c11185b6>] mnt_want_write+0x1e/0x3e #1: (&type->i_mutex_dir_key#4){+.+.+.}, at: [<c11078ee>] do_last+0x245/0xe40 #2: (sb_internal#2){++++.+}, at: [<c122c9e0>] xfs_trans_alloc+0x1f/0x35 #3: (&(&ip->i_lock)->mr_lock/1){+.+...}, at: [<c126cd1b>] xfs_ilock+0x100/0x1f1 #4: (&(&ip->i_lock)->mr_lock){++++-.}, at: [<c126cf52>] xfs_ilock_nowait+0x105/0x22f #5: (&dqp->q_qlock){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 torvalds#6: (&xfs_dquot_other_class){+.+...}, at: [<c12902fb>] xfs_trans_dqlockedjoin+0x57/0x64 The lockdep annotation for dquot lock nesting only understands locking for user and "other" dquots, not user, group and quota dquots. Fix the annotations to match the locking heirarchy we now have. Reported-by: Michael L. Semon <[email protected]> Signed-off-by: Dave Chinner <[email protected]> Reviewed-by: Ben Myers <[email protected]> Signed-off-by: Ben Myers <[email protected]> (cherry picked from commit f112a04)

Booting a mx6 with CONFIG_PROVE_LOCKING we get: ====================================================== [ INFO: possible circular locking dependency detected ] 3.12.0-rc4-next-20131009+ torvalds#34 Not tainted ------------------------------------------------------- swapper/0/1 is trying to acquire lock: (&imx_drm_device->mutex){+.+.+.}, at: [<804575a8>] imx_drm_encoder_get_mux_id+0x28/0x98 but task is already holding lock: (&crtc->mutex){+.+...}, at: [<802fe778>] drm_modeset_lock_all+0x40/0x54 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&crtc->mutex){+.+...}: [<800777d0>] __lock_acquire+0x18d4/0x1c24 [<80077fec>] lock_acquire+0x68/0x7c [<805ead5c>] _mutex_lock_nest_lock+0x58/0x3a8 [<802fec50>] drm_crtc_init+0x48/0xa8 [<80457c88>] imx_drm_add_crtc+0xd4/0x144 [<8045e2e8>] ipu_drm_probe+0x114/0x1fc [<80312278>] platform_drv_probe+0x20/0x50 [<80310c68>] driver_probe_device+0x110/0x22c [<80310e20>] __driver_attach+0x9c/0xa0 [<8030f218>] bus_for_each_dev+0x5c/0x90 [<80310750>] driver_attach+0x20/0x28 [<8031034c>] bus_add_driver+0xdc/0x1dc [<803114d8>] driver_register+0x80/0xfc [<80312198>] __platform_driver_register+0x50/0x64 [<808172fc>] ipu_drm_driver_init+0x18/0x20 [<800088c0>] do_one_initcall+0xfc/0x160 [<807e7c5c>] kernel_init_freeable+0x104/0x1d4 [<805e2930>] kernel_init+0x10/0xec [<8000ea68>] ret_from_fork+0x14/0x2c -> #1 (&dev->mode_config.mutex){+.+.+.}: [<800777d0>] __lock_acquire+0x18d4/0x1c24 [<80077fec>] lock_acquire+0x68/0x7c [<805eb100>] mutex_lock_nested+0x54/0x3a4 [<802fe758>] drm_modeset_lock_all+0x20/0x54 [<802fead4>] drm_encoder_init+0x20/0x7c [<80457ae4>] imx_drm_add_encoder+0x88/0xec [<80459838>] imx_ldb_probe+0x344/0x4fc [<80312278>] platform_drv_probe+0x20/0x50 [<80310c68>] driver_probe_device+0x110/0x22c [<80310e20>] __driver_attach+0x9c/0xa0 [<8030f218>] bus_for_each_dev+0x5c/0x90 [<80310750>] driver_attach+0x20/0x28 [<8031034c>] bus_add_driver+0xdc/0x1dc [<803114d8>] driver_register+0x80/0xfc [<80312198>] __platform_driver_register+0x50/0x64 [<8081722c>] imx_ldb_driver_init+0x18/0x20 [<800088c0>] do_one_initcall+0xfc/0x160 [<807e7c5c>] kernel_init_freeable+0x104/0x1d4 [<805e2930>] kernel_init+0x10/0xec [<8000ea68>] ret_from_fork+0x14/0x2c -> #0 (&imx_drm_device->mutex){+.+.+.}: [<805e510c>] print_circular_bug+0x74/0x2e0 [<80077ad0>] __lock_acquire+0x1bd4/0x1c24 [<80077fec>] lock_acquire+0x68/0x7c [<805eb100>] mutex_lock_nested+0x54/0x3a4 [<804575a8>] imx_drm_encoder_get_mux_id+0x28/0x98 [<80459a98>] imx_ldb_encoder_prepare+0x34/0x114 [<802ef724>] drm_crtc_helper_set_mode+0x1f0/0x4c0 [<802f0344>] drm_crtc_helper_set_config+0x828/0x99c [<802ff270>] drm_mode_set_config_internal+0x5c/0xdc [<802eebe0>] drm_fb_helper_set_par+0x50/0xb4 [<802af580>] fbcon_init+0x490/0x500 [<802dd104>] visual_init+0xa8/0xf8 [<802df414>] do_bind_con_driver+0x140/0x37c [<802df764>] do_take_over_console+0x114/0x1c4 [<802af65c>] do_fbcon_takeover+0x6c/0xd4 [<802b2b30>] fbcon_event_notify+0x7c8/0x818 [<80049954>] notifier_call_chain+0x4c/0x8c [<80049cd8>] __blocking_notifier_call_chain+0x50/0x68 [<80049d10>] blocking_notifier_call_chain+0x20/0x28 [<802a75f0>] fb_notifier_call_chain+0x1c/0x24 [<802a9224>] register_framebuffer+0x188/0x268 [<802ee994>] drm_fb_helper_initial_config+0x2bc/0x4b8 [<802f118c>] drm_fbdev_cma_init+0x7c/0xec [<80817288>] imx_fb_helper_init+0x54/0x90 [<800088c0>] do_one_initcall+0xfc/0x160 [<807e7c5c>] kernel_init_freeable+0x104/0x1d4 [<805e2930>] kernel_init+0x10/0xec [<8000ea68>] ret_from_fork+0x14/0x2c other info that might help us debug this: Chain exists of: &imx_drm_device->mutex --> &dev->mode_config.mutex --> &crtc->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&crtc->mutex); lock(&dev->mode_config.mutex); lock(&crtc->mutex); lock(&imx_drm_device->mutex); *** DEADLOCK *** 6 locks held by swapper/0/1: #0: (registration_lock){+.+.+.}, at: [<802a90bc>] register_framebuffer+0x20/0x268 #1: (&fb_info->lock){+.+.+.}, at: [<802a7a90>] lock_fb_info+0x20/0x44 #2: (console_lock){+.+.+.}, at: [<802a9218>] register_framebuffer+0x17c/0x268 #3: ((fb_notifier_list).rwsem){.+.+.+}, at: [<80049cbc>] __blocking_notifier_call_chain+0x34/0x68 #4: (&dev->mode_config.mutex){+.+.+.}, at: [<802fe758>] drm_modeset_lock_all+0x20/0x54 #5: (&crtc->mutex){+.+...}, at: [<802fe778>] drm_modeset_lock_all+0x40/0x54 In order to avoid this lockdep warning, remove the locking from imx_drm_encoder_get_mux_id() and imx_drm_crtc_panel_format_pins(). Tested on a mx6sabrelite and mx53qsb. Reported-by: Russell King <[email protected]> Tested-by: Russell King <[email protected]> Signed-off-by: Fabio Estevam <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

If EM Transmit bit is busy during init ata_msleep() is called. It is wrong - msleep() should be used instead of ata_msleep(), because if EM Transmit bit is busy for one port, it will be busy for all other ports too, so using ata_msleep() causes wasting tries for another ports. The most common scenario looks like that now (six ports try to transmit a LED meaasege): - port #0 tries for the 1st time and succeeds - ports #1-5 try for the 1st time and sleeps - port #1 tries for the 2nd time and succeeds - ports #2-5 try for the 2nd time and sleeps - port #2 tries for the 3rd time and succeeds - ports #3-5 try for the 3rd time and sleeps - port #3 tries for the 4th time and succeeds - ports #4-5 try for the 4th time and sleeps - port #4 tries for the 5th time and succeeds - port #5 tries for the 5th time and sleeps At this moment port #5 wasted all its five tries and failed to initialize. Because there are only 5 (EM_MAX_RETRY) tries available usually only five ports succeed to initialize. The sixth port and next ones usually will fail. If msleep() is used instead of ata_msleep() the first port succeeds to initialize in the first try and next ones usually succeed to initialize in the second try. tj: updated comment Signed-off-by: Lukasz Dorau <[email protected]> Signed-off-by: Tejun Heo <[email protected]>

Andrey reported the following report: ERROR: AddressSanitizer: heap-buffer-overflow on address ffff8800359c99f3 ffff8800359c99f3 is located 0 bytes to the right of 243-byte region [ffff8800359c9900, ffff8800359c99f3) Accessed by thread T13003: #0 ffffffff810dd2da (asan_report_error+0x32a/0x440) #1 ffffffff810dc6b0 (asan_check_region+0x30/0x40) #2 ffffffff810dd4d3 (__tsan_write1+0x13/0x20) #3 ffffffff811cd19e (ftrace_regex_release+0x1be/0x260) #4 ffffffff812a1065 (__fput+0x155/0x360) #5 ffffffff812a12de (____fput+0x1e/0x30) torvalds#6 ffffffff8111708d (task_work_run+0x10d/0x140) torvalds#7 ffffffff810ea043 (do_exit+0x433/0x11f0) torvalds#8 ffffffff810eaee4 (do_group_exit+0x84/0x130) torvalds#9 ffffffff810eafb1 (SyS_exit_group+0x21/0x30) torvalds#10 ffffffff81928782 (system_call_fastpath+0x16/0x1b) Allocated by thread T5167: #0 ffffffff810dc778 (asan_slab_alloc+0x48/0xc0) #1 ffffffff8128337c (__kmalloc+0xbc/0x500) #2 ffffffff811d9d54 (trace_parser_get_init+0x34/0x90) #3 ffffffff811cd7b3 (ftrace_regex_open+0x83/0x2e0) #4 ffffffff811cda7d (ftrace_filter_open+0x2d/0x40) #5 ffffffff8129b4ff (do_dentry_open+0x32f/0x430) torvalds#6 ffffffff8129b668 (finish_open+0x68/0xa0) torvalds#7 ffffffff812b66ac (do_last+0xb8c/0x1710) torvalds#8 ffffffff812b7350 (path_openat+0x120/0xb50) torvalds#9 ffffffff812b8884 (do_filp_open+0x54/0xb0) torvalds#10 ffffffff8129d36c (do_sys_open+0x1ac/0x2c0) torvalds#11 ffffffff8129d4b7 (SyS_open+0x37/0x50) torvalds#12 ffffffff81928782 (system_call_fastpath+0x16/0x1b) Shadow bytes around the buggy address: ffff8800359c9700: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd ffff8800359c9780: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa ffff8800359c9800: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9880: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>ffff8800359c9980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[03]fb ffff8800359c9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa ffff8800359c9b00: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00 ffff8800359c9b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8800359c9c00: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap redzone: fa Heap kmalloc redzone: fb Freed heap region: fd Shadow gap: fe The out-of-bounds access happens on 'parser->buffer[parser->idx] = 0;' Although the crash happened in ftrace_regex_open() the real bug occurred in trace_get_user() where there's an incrementation to parser->idx without a check against the size. The way it is triggered is if userspace sends in 128 characters (EVENT_BUF_SIZE + 1), the loop that reads the last character stores it and then breaks out because there is no more characters. Then the last character is read to determine what to do next, and the index is incremented without checking size. Then the caller of trace_get_user() usually nulls out the last character with a zero, but since the index is equal to the size, it writes a nul character after the allocated space, which can corrupt memory. Luckily, only root user has write access to this file. Link: http://lkml.kernel.org/r/[email protected] Reported-by: Andrey Konovalov <[email protected]> Signed-off-by: Steven Rostedt <[email protected]>

…ux/kernel/git/tip/tip Pull x86 boot changes from Ingo Molnar: "Two changes that prettify and compactify the SMP bootup output from: smpboot: Booting Node 0, Processors #1 #2 #3 OK smpboot: Booting Node 1, Processors #4 #5 torvalds#6 torvalds#7 OK smpboot: Booting Node 2, Processors torvalds#8 torvalds#9 torvalds#10 torvalds#11 OK smpboot: Booting Node 3, Processors torvalds#12 torvalds#13 torvalds#14 torvalds#15 OK Brought up 16 CPUs to something like: x86: Booting SMP configuration: .... node #0, CPUs: #1 #2 #3 .... node #1, CPUs: #4 #5 torvalds#6 torvalds#7 .... node #2, CPUs: torvalds#8 torvalds#9 torvalds#10 torvalds#11 .... node #3, CPUs: torvalds#12 torvalds#13 torvalds#14 torvalds#15 x86: Booted up 4 nodes, 16 CPUs" * 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Further compress CPUs bootup message x86: Improve the printout of the SMP bootup CPU table

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test IDE of sh2007 #4

test IDE of sh2007 #4

mitake commented Sep 5, 2012

test IDE of sh2007 #4

test IDE of sh2007 #4

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mitake commented Sep 5, 2012