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ODROID-XU4: Enable TUN module #119
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tobetter
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hardkernel:odroidxu4-v4.2-rc1
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scotte:odroidxu4-v4.2-rc1_tun
Aug 11, 2015
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ODROID-XU4: Enable TUN module #119
tobetter
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hardkernel:odroidxu4-v4.2-rc1
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scotte:odroidxu4-v4.2-rc1_tun
Aug 11, 2015
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tobetter
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Aug 11, 2015
ODROID-XU4: Enable TUN module
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Dmole
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Feb 23, 2017
commit fc98c3c upstream. Use rcuidle console tracepoint because, apparently, it may be issued from an idle CPU: hw-breakpoint: Failed to enable monitor mode on CPU 0. hw-breakpoint: CPU 0 failed to disable vector catch =============================== [ ERR: suspicious RCU usage. ] 4.10.0-rc8-next-20170215+ hardkernel#119 Not tainted ------------------------------- ./include/trace/events/printk.h:32 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 2, debug_locks = 0 RCU used illegally from extended quiescent state! 2 locks held by swapper/0/0: #0: (cpu_pm_notifier_lock){......}, at: [<c0237e2c>] cpu_pm_exit+0x10/0x54 hardkernel#1: (console_lock){+.+.+.}, at: [<c01ab350>] vprintk_emit+0x264/0x474 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc8-next-20170215+ hardkernel#119 Hardware name: Generic OMAP4 (Flattened Device Tree) console_unlock vprintk_emit vprintk_default printk reset_ctrl_regs dbg_cpu_pm_notify notifier_call_chain cpu_pm_exit omap_enter_idle_coupled cpuidle_enter_state cpuidle_enter_state_coupled do_idle cpu_startup_entry start_kernel This RCU warning, however, is suppressed by lockdep_off() in printk(). lockdep_off() increments the ->lockdep_recursion counter and thus disables RCU_LOCKDEP_WARN() and debug_lockdep_rcu_enabled(), which want lockdep to be enabled "current->lockdep_recursion == 0". Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Sergey Senozhatsky <[email protected]> Reported-by: Tony Lindgren <[email protected]> Tested-by: Tony Lindgren <[email protected]> Acked-by: Paul E. McKenney <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Lindgren <[email protected]> Cc: Russell King <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
Dmole
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Feb 23, 2017
commit fc98c3c upstream. Use rcuidle console tracepoint because, apparently, it may be issued from an idle CPU: hw-breakpoint: Failed to enable monitor mode on CPU 0. hw-breakpoint: CPU 0 failed to disable vector catch =============================== [ ERR: suspicious RCU usage. ] 4.10.0-rc8-next-20170215+ hardkernel#119 Not tainted ------------------------------- ./include/trace/events/printk.h:32 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 2, debug_locks = 0 RCU used illegally from extended quiescent state! 2 locks held by swapper/0/0: #0: (cpu_pm_notifier_lock){......}, at: [<c0237e2c>] cpu_pm_exit+0x10/0x54 hardkernel#1: (console_lock){+.+.+.}, at: [<c01ab350>] vprintk_emit+0x264/0x474 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc8-next-20170215+ hardkernel#119 Hardware name: Generic OMAP4 (Flattened Device Tree) console_unlock vprintk_emit vprintk_default printk reset_ctrl_regs dbg_cpu_pm_notify notifier_call_chain cpu_pm_exit omap_enter_idle_coupled cpuidle_enter_state cpuidle_enter_state_coupled do_idle cpu_startup_entry start_kernel This RCU warning, however, is suppressed by lockdep_off() in printk(). lockdep_off() increments the ->lockdep_recursion counter and thus disables RCU_LOCKDEP_WARN() and debug_lockdep_rcu_enabled(), which want lockdep to be enabled "current->lockdep_recursion == 0". Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Sergey Senozhatsky <[email protected]> Reported-by: Tony Lindgren <[email protected]> Tested-by: Tony Lindgren <[email protected]> Acked-by: Paul E. McKenney <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Lindgren <[email protected]> Cc: Russell King <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
Dmole
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Jul 22, 2017
commit 87b60cf upstream. Dmitry reported uses after free in qdisc code [1] The problem here is that ops->init() can return an error. qdisc_create_dflt() then call ops->destroy(), while qdisc_create() does _not_ call it. Four qdisc chose to call their own ops->destroy(), assuming their caller would not. This patch makes sure qdisc_create() calls ops->destroy() and fixes the four qdisc to avoid double free. [1] BUG: KASAN: use-after-free in mq_destroy+0x242/0x290 net/sched/sch_mq.c:33 at addr ffff8801d415d440 Read of size 8 by task syz-executor2/5030 CPU: 0 PID: 5030 Comm: syz-executor2 Not tainted 4.3.5-smp-DEV hardkernel#119 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000046 ffff8801b435b870 ffffffff81bbbed4 ffff8801db000400 ffff8801d415d440 ffff8801d415dc40 ffff8801c4988510 ffff8801b435b898 ffffffff816682b1 ffff8801b435b928 ffff8801d415d440 ffff8801c49880c0 Call Trace: [<ffffffff81bbbed4>] __dump_stack lib/dump_stack.c:15 [inline] [<ffffffff81bbbed4>] dump_stack+0x6c/0x98 lib/dump_stack.c:51 [<ffffffff816682b1>] kasan_object_err+0x21/0x70 mm/kasan/report.c:158 [<ffffffff81668524>] print_address_description mm/kasan/report.c:196 [inline] [<ffffffff81668524>] kasan_report_error+0x1b4/0x4b0 mm/kasan/report.c:285 [<ffffffff81668953>] kasan_report mm/kasan/report.c:305 [inline] [<ffffffff81668953>] __asan_report_load8_noabort+0x43/0x50 mm/kasan/report.c:326 [<ffffffff82527b02>] mq_destroy+0x242/0x290 net/sched/sch_mq.c:33 [<ffffffff82524bdd>] qdisc_destroy+0x12d/0x290 net/sched/sch_generic.c:953 [<ffffffff82524e30>] qdisc_create_dflt+0xf0/0x120 net/sched/sch_generic.c:848 [<ffffffff8252550d>] attach_default_qdiscs net/sched/sch_generic.c:1029 [inline] [<ffffffff8252550d>] dev_activate+0x6ad/0x880 net/sched/sch_generic.c:1064 [<ffffffff824b1db1>] __dev_open+0x221/0x320 net/core/dev.c:1403 [<ffffffff824b24ce>] __dev_change_flags+0x15e/0x3e0 net/core/dev.c:6858 [<ffffffff824b27de>] dev_change_flags+0x8e/0x140 net/core/dev.c:6926 [<ffffffff824f5bf6>] dev_ifsioc+0x446/0x890 net/core/dev_ioctl.c:260 [<ffffffff824f61fa>] dev_ioctl+0x1ba/0xb80 net/core/dev_ioctl.c:546 [<ffffffff82430509>] sock_do_ioctl+0x99/0xb0 net/socket.c:879 [<ffffffff82430d30>] sock_ioctl+0x2a0/0x390 net/socket.c:958 [<ffffffff816f3b68>] vfs_ioctl fs/ioctl.c:44 [inline] [<ffffffff816f3b68>] do_vfs_ioctl+0x8a8/0xe50 fs/ioctl.c:611 [<ffffffff816f41a4>] SYSC_ioctl fs/ioctl.c:626 [inline] [<ffffffff816f41a4>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:617 [<ffffffff8123e357>] entry_SYSCALL_64_fastpath+0x12/0x17 Signed-off-by: Eric Dumazet <[email protected]> Reported-by: Dmitry Vyukov <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
Dmole
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Jul 22, 2017
commit 87b60cf upstream. Dmitry reported uses after free in qdisc code [1] The problem here is that ops->init() can return an error. qdisc_create_dflt() then call ops->destroy(), while qdisc_create() does _not_ call it. Four qdisc chose to call their own ops->destroy(), assuming their caller would not. This patch makes sure qdisc_create() calls ops->destroy() and fixes the four qdisc to avoid double free. [1] BUG: KASAN: use-after-free in mq_destroy+0x242/0x290 net/sched/sch_mq.c:33 at addr ffff8801d415d440 Read of size 8 by task syz-executor2/5030 CPU: 0 PID: 5030 Comm: syz-executor2 Not tainted 4.3.5-smp-DEV hardkernel#119 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000046 ffff8801b435b870 ffffffff81bbbed4 ffff8801db000400 ffff8801d415d440 ffff8801d415dc40 ffff8801c4988510 ffff8801b435b898 ffffffff816682b1 ffff8801b435b928 ffff8801d415d440 ffff8801c49880c0 Call Trace: [<ffffffff81bbbed4>] __dump_stack lib/dump_stack.c:15 [inline] [<ffffffff81bbbed4>] dump_stack+0x6c/0x98 lib/dump_stack.c:51 [<ffffffff816682b1>] kasan_object_err+0x21/0x70 mm/kasan/report.c:158 [<ffffffff81668524>] print_address_description mm/kasan/report.c:196 [inline] [<ffffffff81668524>] kasan_report_error+0x1b4/0x4b0 mm/kasan/report.c:285 [<ffffffff81668953>] kasan_report mm/kasan/report.c:305 [inline] [<ffffffff81668953>] __asan_report_load8_noabort+0x43/0x50 mm/kasan/report.c:326 [<ffffffff82527b02>] mq_destroy+0x242/0x290 net/sched/sch_mq.c:33 [<ffffffff82524bdd>] qdisc_destroy+0x12d/0x290 net/sched/sch_generic.c:953 [<ffffffff82524e30>] qdisc_create_dflt+0xf0/0x120 net/sched/sch_generic.c:848 [<ffffffff8252550d>] attach_default_qdiscs net/sched/sch_generic.c:1029 [inline] [<ffffffff8252550d>] dev_activate+0x6ad/0x880 net/sched/sch_generic.c:1064 [<ffffffff824b1db1>] __dev_open+0x221/0x320 net/core/dev.c:1403 [<ffffffff824b24ce>] __dev_change_flags+0x15e/0x3e0 net/core/dev.c:6858 [<ffffffff824b27de>] dev_change_flags+0x8e/0x140 net/core/dev.c:6926 [<ffffffff824f5bf6>] dev_ifsioc+0x446/0x890 net/core/dev_ioctl.c:260 [<ffffffff824f61fa>] dev_ioctl+0x1ba/0xb80 net/core/dev_ioctl.c:546 [<ffffffff82430509>] sock_do_ioctl+0x99/0xb0 net/socket.c:879 [<ffffffff82430d30>] sock_ioctl+0x2a0/0x390 net/socket.c:958 [<ffffffff816f3b68>] vfs_ioctl fs/ioctl.c:44 [inline] [<ffffffff816f3b68>] do_vfs_ioctl+0x8a8/0xe50 fs/ioctl.c:611 [<ffffffff816f41a4>] SYSC_ioctl fs/ioctl.c:626 [inline] [<ffffffff816f41a4>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:617 [<ffffffff8123e357>] entry_SYSCALL_64_fastpath+0x12/0x17 Signed-off-by: Eric Dumazet <[email protected]> Reported-by: Dmitry Vyukov <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
mdrjr
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Sep 4, 2017
commit fc98c3c upstream. Use rcuidle console tracepoint because, apparently, it may be issued from an idle CPU: hw-breakpoint: Failed to enable monitor mode on CPU 0. hw-breakpoint: CPU 0 failed to disable vector catch =============================== [ ERR: suspicious RCU usage. ] 4.10.0-rc8-next-20170215+ #119 Not tainted ------------------------------- ./include/trace/events/printk.h:32 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 2, debug_locks = 0 RCU used illegally from extended quiescent state! 2 locks held by swapper/0/0: #0: (cpu_pm_notifier_lock){......}, at: [<c0237e2c>] cpu_pm_exit+0x10/0x54 #1: (console_lock){+.+.+.}, at: [<c01ab350>] vprintk_emit+0x264/0x474 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc8-next-20170215+ #119 Hardware name: Generic OMAP4 (Flattened Device Tree) console_unlock vprintk_emit vprintk_default printk reset_ctrl_regs dbg_cpu_pm_notify notifier_call_chain cpu_pm_exit omap_enter_idle_coupled cpuidle_enter_state cpuidle_enter_state_coupled do_idle cpu_startup_entry start_kernel This RCU warning, however, is suppressed by lockdep_off() in printk(). lockdep_off() increments the ->lockdep_recursion counter and thus disables RCU_LOCKDEP_WARN() and debug_lockdep_rcu_enabled(), which want lockdep to be enabled "current->lockdep_recursion == 0". Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Sergey Senozhatsky <[email protected]> Reported-by: Tony Lindgren <[email protected]> Tested-by: Tony Lindgren <[email protected]> Acked-by: Paul E. McKenney <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Lindgren <[email protected]> Cc: Russell King <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> [wt: changes are in kernel/printk.c in 3.10] Signed-off-by: Willy Tarreau <[email protected]>
mdrjr
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Dec 4, 2017
commit ff16567 upstream. acpi_remove_pm_notifier() ends up calling flush_workqueue() while holding acpi_pm_notifier_lock, and that same lock is taken by by the work via acpi_pm_notify_handler(). This can deadlock. To fix the problem let's split the single lock into two: one to protect the dev->wakeup between the work vs. add/remove, and another one to handle notifier installation vs. removal. After commit a1d1493 "workqueue/lockdep: 'Fix' flush_work() annotation" I was able to kill the machine (Intel Braswell) very easily with 'powertop --auto-tune', runtime suspending i915, and trying to wake it up via the USB keyboard. The cases when it didn't die are presumably explained by lockdep getting disabled by something else (cpu hotplug locking issues usually). Fortunately I still got a lockdep report over netconsole (trickling in very slowly), even though the machine was otherwise practically dead: [ 112.179806] ====================================================== [ 114.670858] WARNING: possible circular locking dependency detected [ 117.155663] 4.13.0-rc6-bsw-bisect-00169-ga1d14934ea4b #119 Not tainted [ 119.658101] ------------------------------------------------------ [ 121.310242] xhci_hcd 0000:00:14.0: xHCI host not responding to stop endpoint command. [ 121.313294] xhci_hcd 0000:00:14.0: xHCI host controller not responding, assume dead [ 121.313346] xhci_hcd 0000:00:14.0: HC died; cleaning up [ 121.313485] usb 1-6: USB disconnect, device number 3 [ 121.313501] usb 1-6.2: USB disconnect, device number 4 [ 134.747383] kworker/0:2/47 is trying to acquire lock: [ 137.220790] (acpi_pm_notifier_lock){+.+.}, at: [<ffffffff813cafdf>] acpi_pm_notify_handler+0x2f/0x80 [ 139.721524] [ 139.721524] but task is already holding lock: [ 144.672922] ((&dpc->work)){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720 [ 147.184450] [ 147.184450] which lock already depends on the new lock. [ 147.184450] [ 154.604711] [ 154.604711] the existing dependency chain (in reverse order) is: [ 159.447888] [ 159.447888] -> #2 ((&dpc->work)){+.+.}: [ 164.183486] __lock_acquire+0x1255/0x13f0 [ 166.504313] lock_acquire+0xb5/0x210 [ 168.778973] process_one_work+0x1b9/0x720 [ 171.030316] worker_thread+0x4c/0x440 [ 173.257184] kthread+0x154/0x190 [ 175.456143] ret_from_fork+0x27/0x40 [ 177.624348] [ 177.624348] -> #1 ("kacpi_notify"){+.+.}: [ 181.850351] __lock_acquire+0x1255/0x13f0 [ 183.941695] lock_acquire+0xb5/0x210 [ 186.046115] flush_workqueue+0xdd/0x510 [ 190.408153] acpi_os_wait_events_complete+0x31/0x40 [ 192.625303] acpi_remove_notify_handler+0x133/0x188 [ 194.820829] acpi_remove_pm_notifier+0x56/0x90 [ 196.989068] acpi_dev_pm_detach+0x5f/0xa0 [ 199.145866] dev_pm_domain_detach+0x27/0x30 [ 201.285614] i2c_device_probe+0x100/0x210 [ 203.411118] driver_probe_device+0x23e/0x310 [ 205.522425] __driver_attach+0xa3/0xb0 [ 207.634268] bus_for_each_dev+0x69/0xa0 [ 209.714797] driver_attach+0x1e/0x20 [ 211.778258] bus_add_driver+0x1bc/0x230 [ 213.837162] driver_register+0x60/0xe0 [ 215.868162] i2c_register_driver+0x42/0x70 [ 217.869551] 0xffffffffa0172017 [ 219.863009] do_one_initcall+0x45/0x170 [ 221.843863] do_init_module+0x5f/0x204 [ 223.817915] load_module+0x225b/0x29b0 [ 225.757234] SyS_finit_module+0xc6/0xd0 [ 227.661851] do_syscall_64+0x5c/0x120 [ 229.536819] return_from_SYSCALL_64+0x0/0x7a [ 231.392444] [ 231.392444] -> #0 (acpi_pm_notifier_lock){+.+.}: [ 235.124914] check_prev_add+0x44e/0x8a0 [ 237.024795] __lock_acquire+0x1255/0x13f0 [ 238.937351] lock_acquire+0xb5/0x210 [ 240.840799] __mutex_lock+0x75/0x940 [ 242.709517] mutex_lock_nested+0x1c/0x20 [ 244.551478] acpi_pm_notify_handler+0x2f/0x80 [ 246.382052] acpi_ev_notify_dispatch+0x44/0x5c [ 248.194412] acpi_os_execute_deferred+0x14/0x30 [ 250.003925] process_one_work+0x1ec/0x720 [ 251.803191] worker_thread+0x4c/0x440 [ 253.605307] kthread+0x154/0x190 [ 255.387498] ret_from_fork+0x27/0x40 [ 257.153175] [ 257.153175] other info that might help us debug this: [ 257.153175] [ 262.324392] Chain exists of: [ 262.324392] acpi_pm_notifier_lock --> "kacpi_notify" --> (&dpc->work) [ 262.324392] [ 267.391997] Possible unsafe locking scenario: [ 267.391997] [ 270.758262] CPU0 CPU1 [ 272.431713] ---- ---- [ 274.060756] lock((&dpc->work)); [ 275.646532] lock("kacpi_notify"); [ 277.260772] lock((&dpc->work)); [ 278.839146] lock(acpi_pm_notifier_lock); [ 280.391902] [ 280.391902] *** DEADLOCK *** [ 280.391902] [ 284.986385] 2 locks held by kworker/0:2/47: [ 286.524895] #0: ("kacpi_notify"){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720 [ 288.112927] #1: ((&dpc->work)){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720 [ 289.727725] Fixes: c072530 (ACPI / PM: Revork the handling of ACPI device wakeup notifications) Signed-off-by: Ville Syrjälä <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
mdrjr
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Feb 27, 2018
[ Upstream commit 8722e09 ] DWC3_DEPCMD_ENDTRANSFER has been witnessed to require around 600 iterations before controller would become idle again after unplugging the USB cable with AIO reads submitted. Bump timeout from 500 iterations to 1000 so dwc3_stop_active_transfer does not receive -ETIMEDOUT and does not WARN: [ 81.326273] ------------[ cut here ]------------ [ 81.335341] WARNING: CPU: 0 PID: 1874 at drivers/usb/dwc3/gadget.c:2627 dwc3_stop_active_transfer.constprop.23+0x69/0xc0 [dwc3] [ 81.347094] Modules linked in: usb_f_fs libcomposite configfs bnep btsdio bluetooth ecdh_generic brcmfmac brcmutil dwc3 intel_powerclamp coretemp ulpi kvm_intel udc_core kvm irqbypass crc32_pclmul crc32c_intel pcbc dwc3_pci aesni_intel aes_i586 crypto_simd cryptd ehci_pci ehci_hcd basincove_gpadc industrialio gpio_keys usbcore usb_common [ 81.378142] CPU: 0 PID: 1874 Comm: irq/34-dwc3 Not tainted 4.14.0-edison+ #119 [ 81.385545] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48 [ 81.394548] task: f5b1be00 task.stack: f420a000 [ 81.399219] EIP: dwc3_stop_active_transfer.constprop.23+0x69/0xc0 [dwc3] [ 81.406086] EFLAGS: 00010086 CPU: 0 [ 81.409672] EAX: 0000001f EBX: f5729800 ECX: c132a2a2 EDX: 00000000 [ 81.416096] ESI: f4054014 EDI: f41cf400 EBP: f420be10 ESP: f420bdf4 [ 81.422521] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 [ 81.428061] CR0: 80050033 CR2: b7a3f000 CR3: 01d94000 CR4: 001006d0 [ 81.434483] Call Trace: [ 81.437063] __dwc3_gadget_ep_disable+0xa3/0x2b0 [dwc3] [ 81.442438] ? _raw_spin_lock_irqsave+0x32/0x40 [ 81.447135] dwc3_gadget_ep_disable+0xbf/0xe0 [dwc3] [ 81.452269] usb_ep_disable+0x1c/0xd0 [udc_core] [ 81.457048] ffs_func_eps_disable.isra.15+0x3b/0x90 [usb_f_fs] [ 81.463070] ffs_func_set_alt+0x7d/0x310 [usb_f_fs] [ 81.468132] ffs_func_disable+0x14/0x20 [usb_f_fs] [ 81.473075] reset_config+0x5b/0x90 [libcomposite] [ 81.478023] composite_disconnect+0x2b/0x50 [libcomposite] [ 81.483685] dwc3_disconnect_gadget+0x39/0x50 [dwc3] [ 81.488808] dwc3_gadget_disconnect_interrupt+0x21b/0x250 [dwc3] [ 81.495014] dwc3_thread_interrupt+0x2a8/0xf70 [dwc3] [ 81.500219] ? __schedule+0x78c/0x7e0 [ 81.504027] irq_thread_fn+0x18/0x30 [ 81.507715] ? irq_thread+0xb7/0x180 [ 81.511400] irq_thread+0x111/0x180 [ 81.515000] ? irq_finalize_oneshot+0xe0/0xe0 [ 81.519490] ? wake_threads_waitq+0x30/0x30 [ 81.523806] kthread+0x107/0x110 [ 81.527131] ? disable_percpu_irq+0x50/0x50 [ 81.531439] ? kthread_stop+0x150/0x150 [ 81.535397] ret_from_fork+0x19/0x24 [ 81.539136] Code: 89 d8 c7 45 ec 00 00 00 00 c7 45 f0 00 00 00 00 c7 45 f4 00 00 00 00 e8 56 ef ff ff 85 c0 74 12 50 68 b9 1c 14 f8 e8 64 0f f7 c8 <0f> ff 58 5a 8d 76 00 8b 83 98 00 00 00 c6 83 a0 00 00 00 00 83 [ 81.559295] ---[ end trace f3133eec81a473b8 ]--- Number of iterations measured on 4 consecutive unplugs: [ 1088.799777] dwc3_send_gadget_ep_cmd(cmd=331016, params={0, 0, 0}) iterated 605 times [ 1222.024986] dwc3_send_gadget_ep_cmd(cmd=331016, params={0, 0, 0}) iterated 580 times [ 1317.590452] dwc3_send_gadget_ep_cmd(cmd=331016, params={0, 0, 0}) iterated 598 times [ 1453.218314] dwc3_send_gadget_ep_cmd(cmd=331016, params={0, 0, 0}) iterated 594 times Signed-off-by: Vincent Pelletier <[email protected]> Signed-off-by: Felipe Balbi <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
mdrjr
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Apr 29, 2018
commit 75a4598 upstream. mlx5 modify_qp() relies on FW that the error will be thrown if wrong state is supplied. The missing check in FW causes the following crash while using XRC_TGT QPs. [ 14.769632] BUG: unable to handle kernel NULL pointer dereference at (null) [ 14.771085] IP: mlx5_ib_modify_qp+0xf60/0x13f0 [ 14.771894] PGD 800000001472e067 P4D 800000001472e067 PUD 14529067 PMD 0 [ 14.773126] Oops: 0002 [#1] SMP PTI [ 14.773763] CPU: 0 PID: 365 Comm: ubsan Not tainted 4.16.0-rc1-00038-g8151138c0793 #119 [ 14.775192] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 14.777522] RIP: 0010:mlx5_ib_modify_qp+0xf60/0x13f0 [ 14.778417] RSP: 0018:ffffbf48001c7bd8 EFLAGS: 00010246 [ 14.779346] RAX: 0000000000000000 RBX: ffff9a8f9447d400 RCX: 0000000000000000 [ 14.780643] RDX: 0000000000000000 RSI: 000000000000000a RDI: 0000000000000000 [ 14.781930] RBP: 0000000000000000 R08: 00000000000217b0 R09: ffffffffbc9c1504 [ 14.783214] R10: fffff4a180519480 R11: ffff9a8f94523600 R12: ffff9a8f9493e240 [ 14.784507] R13: ffff9a8f9447d738 R14: 000000000000050a R15: 0000000000000000 [ 14.785800] FS: 00007f545b466700(0000) GS:ffff9a8f9fc00000(0000) knlGS:0000000000000000 [ 14.787073] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 14.787792] CR2: 0000000000000000 CR3: 00000000144be000 CR4: 00000000000006b0 [ 14.788689] Call Trace: [ 14.789007] _ib_modify_qp+0x71/0x120 [ 14.789475] modify_qp.isra.20+0x207/0x2f0 [ 14.790010] ib_uverbs_modify_qp+0x90/0xe0 [ 14.790532] ib_uverbs_write+0x1d2/0x3c0 [ 14.791049] ? __handle_mm_fault+0x93c/0xe40 [ 14.791644] __vfs_write+0x36/0x180 [ 14.792096] ? handle_mm_fault+0xc1/0x210 [ 14.792601] vfs_write+0xad/0x1e0 [ 14.793018] SyS_write+0x52/0xc0 [ 14.793422] do_syscall_64+0x75/0x180 [ 14.793888] entry_SYSCALL_64_after_hwframe+0x21/0x86 [ 14.794527] RIP: 0033:0x7f545ad76099 [ 14.794975] RSP: 002b:00007ffd78787468 EFLAGS: 00000287 ORIG_RAX: 0000000000000001 [ 14.795958] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f545ad76099 [ 14.797075] RDX: 0000000000000078 RSI: 0000000020009000 RDI: 0000000000000003 [ 14.798140] RBP: 00007ffd78787470 R08: 00007ffd78787480 R09: 00007ffd78787480 [ 14.799207] R10: 00007ffd78787480 R11: 0000000000000287 R12: 00005599ada98760 [ 14.800277] R13: 00007ffd78787560 R14: 0000000000000000 R15: 0000000000000000 [ 14.801341] Code: 4c 8b 1c 24 48 8b 83 70 02 00 00 48 c7 83 cc 02 00 00 00 00 00 00 48 c7 83 24 03 00 00 00 00 00 00 c7 83 2c 03 00 00 00 00 00 00 <c7> 00 00 00 00 00 48 8b 83 70 02 00 00 c7 40 04 00 00 00 00 4c [ 14.804012] RIP: mlx5_ib_modify_qp+0xf60/0x13f0 RSP: ffffbf48001c7bd8 [ 14.804838] CR2: 0000000000000000 [ 14.805288] ---[ end trace 3f1da0df5c8b7c37 ]--- Cc: syzkaller <[email protected]> Reported-by: Maor Gottlieb <[email protected]> Signed-off-by: Leon Romanovsky <[email protected]> Signed-off-by: Doug Ledford <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
mihailescu2m
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Feb 27, 2019
We've been seeing hard-to-trigger psi crashes when running inside VM instances: divide error: 0000 [#1] SMP PTI Modules linked in: [...] CPU: 0 PID: 212 Comm: kworker/0:2 Not tainted 4.16.18-119_fbk9_3817_gfe944c98d695 hardkernel#119 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Workqueue: events psi_clock RIP: 0010:psi_update_stats+0x270/0x490 RSP: 0018:ffffc90001117e10 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8800a35a13f8 RDX: 0000000000000000 RSI: ffff8800a35a1340 RDI: 0000000000000000 RBP: 0000000000000658 R08: ffff8800a35a1470 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 00000000000f8502 FS: 0000000000000000(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbe370fa000 CR3: 00000000b1e3a000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: psi_clock+0x12/0x50 process_one_work+0x1e0/0x390 worker_thread+0x2b/0x3c0 ? rescuer_thread+0x330/0x330 kthread+0x113/0x130 ? kthread_create_worker_on_cpu+0x40/0x40 ? SyS_exit_group+0x10/0x10 ret_from_fork+0x35/0x40 Code: 48 0f 47 c7 48 01 c2 45 85 e4 48 89 16 0f 85 e6 00 00 00 4c 8b 49 10 4c 8b 51 08 49 69 d9 f2 07 00 00 48 6b c0 64 4c 8b 29 31 d2 <48> f7 f7 49 69 d5 8d 06 00 00 48 89 c5 4c 69 f0 00 98 0b 00 48 The Code-line points to `period` being 0 inside update_stats(), and we divide by that when calculating that period's pressure percentage. The elapsed period should never be 0. The reason this can happen is due to an off-by-one in the idle time / missing period calculation combined with a coarse sched_clock() in the virtual machine. The target time for aggregation is advanced into the future on a fixed grid to prevent clock drift. So when an aggregation runs after some idle period, we can not just set it to "now + psi_period", but have to calculate the downtime and advance the target time relative to itself. However, if the aggregator was disabled exactly one psi_period (ns), we drop one idle period in the calculation due to a > when we should do >=. In that case, next_update will be advanced from 'now - psi_period' to 'now' when it should be moved to 'now + psi_period'. The run finishes with last_update == next_update == sched_clock(). With hardware clocks, this exact nanosecond match isn't likely in the first place; but if it does happen, the clock will still have moved on and the period non-zero by the time the worker runs. A pointlessly short period, but besides the extra work, no harm no foul. However, a slow sched_clock() like we have on VMs might not have advanced either by the time the worker runs again. And when we calculate the elapsed period, the result, our pressure divisor, will be 0. Ouch. Fix this by correctly handling the situation when the elapsed time between aggregation runs is precisely two periods, and advance the expiration timestamp correctly to period into the future. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Johannes Weiner <[email protected]> Reported-by: Łukasz Siudut <[email protected] Reviewed-by: Andrew Morton <[email protected]> Cc: Peter Zijlstra <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
ardje
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Feb 5, 2020
commit f1f27ad upstream. The task which created the MID may be gone by the time cifsd attempts to call the callbacks on MIDs from cifs_reconnect(). This leads to a use-after-free of the task struct in cifs_wake_up_task: ================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x31a0/0x3270 Read of size 8 at addr ffff8880103e3a68 by task cifsd/630 CPU: 0 PID: 630 Comm: cifsd Not tainted 5.5.0-rc6+ hardkernel#119 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Call Trace: dump_stack+0x8e/0xcb print_address_description.constprop.5+0x1d3/0x3c0 ? __lock_acquire+0x31a0/0x3270 __kasan_report+0x152/0x1aa ? __lock_acquire+0x31a0/0x3270 ? __lock_acquire+0x31a0/0x3270 kasan_report+0xe/0x20 __lock_acquire+0x31a0/0x3270 ? __wake_up_common+0x1dc/0x630 ? _raw_spin_unlock_irqrestore+0x4c/0x60 ? mark_held_locks+0xf0/0xf0 ? _raw_spin_unlock_irqrestore+0x39/0x60 ? __wake_up_common_lock+0xd5/0x130 ? __wake_up_common+0x630/0x630 lock_acquire+0x13f/0x330 ? try_to_wake_up+0xa3/0x19e0 _raw_spin_lock_irqsave+0x38/0x50 ? try_to_wake_up+0xa3/0x19e0 try_to_wake_up+0xa3/0x19e0 ? cifs_compound_callback+0x178/0x210 ? set_cpus_allowed_ptr+0x10/0x10 cifs_reconnect+0xa1c/0x15d0 ? generic_ip_connect+0x1860/0x1860 ? rwlock_bug.part.0+0x90/0x90 cifs_readv_from_socket+0x479/0x690 cifs_read_from_socket+0x9d/0xe0 ? cifs_readv_from_socket+0x690/0x690 ? mempool_resize+0x690/0x690 ? rwlock_bug.part.0+0x90/0x90 ? memset+0x1f/0x40 ? allocate_buffers+0xff/0x340 cifs_demultiplex_thread+0x388/0x2a50 ? cifs_handle_standard+0x610/0x610 ? rcu_read_lock_held_common+0x120/0x120 ? mark_lock+0x11b/0xc00 ? __lock_acquire+0x14ed/0x3270 ? __kthread_parkme+0x78/0x100 ? lockdep_hardirqs_on+0x3e8/0x560 ? lock_downgrade+0x6a0/0x6a0 ? lockdep_hardirqs_on+0x3e8/0x560 ? _raw_spin_unlock_irqrestore+0x39/0x60 ? cifs_handle_standard+0x610/0x610 kthread+0x2bb/0x3a0 ? kthread_create_worker_on_cpu+0xc0/0xc0 ret_from_fork+0x3a/0x50 Allocated by task 649: save_stack+0x19/0x70 __kasan_kmalloc.constprop.5+0xa6/0xf0 kmem_cache_alloc+0x107/0x320 copy_process+0x17bc/0x5370 _do_fork+0x103/0xbf0 __x64_sys_clone+0x168/0x1e0 do_syscall_64+0x9b/0xec0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 0: save_stack+0x19/0x70 __kasan_slab_free+0x11d/0x160 kmem_cache_free+0xb5/0x3d0 rcu_core+0x52f/0x1230 __do_softirq+0x24d/0x962 The buggy address belongs to the object at ffff8880103e32c0 which belongs to the cache task_struct of size 6016 The buggy address is located 1960 bytes inside of 6016-byte region [ffff8880103e32c0, ffff8880103e4a40) The buggy address belongs to the page: page:ffffea000040f800 refcount:1 mapcount:0 mapping:ffff8880108da5c0 index:0xffff8880103e4c00 compound_mapcount: 0 raw: 4000000000010200 ffffea00001f2208 ffffea00001e3408 ffff8880108da5c0 raw: ffff8880103e4c00 0000000000050003 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880103e3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880103e3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880103e3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880103e3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880103e3b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== This can be reliably reproduced by adding the below delay to cifs_reconnect(), running find(1) on the mount, restarting the samba server while find is running, and killing find during the delay: spin_unlock(&GlobalMid_Lock); mutex_unlock(&server->srv_mutex); + msleep(10000); + cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__); list_for_each_safe(tmp, tmp2, &retry_list) { mid_entry = list_entry(tmp, struct mid_q_entry, qhead); Fix this by holding a reference to the task struct until the MID is freed. Signed-off-by: Vincent Whitchurch <[email protected]> Signed-off-by: Steve French <[email protected]> CC: Stable <[email protected]> Reviewed-by: Paulo Alcantara (SUSE) <[email protected]> Reviewed-by: Pavel Shilovsky <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
mdrjr
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Jun 29, 2020
commit f1f27ad upstream. The task which created the MID may be gone by the time cifsd attempts to call the callbacks on MIDs from cifs_reconnect(). This leads to a use-after-free of the task struct in cifs_wake_up_task: ================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x31a0/0x3270 Read of size 8 at addr ffff8880103e3a68 by task cifsd/630 CPU: 0 PID: 630 Comm: cifsd Not tainted 5.5.0-rc6+ #119 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Call Trace: dump_stack+0x8e/0xcb print_address_description.constprop.5+0x1d3/0x3c0 ? __lock_acquire+0x31a0/0x3270 __kasan_report+0x152/0x1aa ? __lock_acquire+0x31a0/0x3270 ? __lock_acquire+0x31a0/0x3270 kasan_report+0xe/0x20 __lock_acquire+0x31a0/0x3270 ? __wake_up_common+0x1dc/0x630 ? _raw_spin_unlock_irqrestore+0x4c/0x60 ? mark_held_locks+0xf0/0xf0 ? _raw_spin_unlock_irqrestore+0x39/0x60 ? __wake_up_common_lock+0xd5/0x130 ? __wake_up_common+0x630/0x630 lock_acquire+0x13f/0x330 ? try_to_wake_up+0xa3/0x19e0 _raw_spin_lock_irqsave+0x38/0x50 ? try_to_wake_up+0xa3/0x19e0 try_to_wake_up+0xa3/0x19e0 ? cifs_compound_callback+0x178/0x210 ? set_cpus_allowed_ptr+0x10/0x10 cifs_reconnect+0xa1c/0x15d0 ? generic_ip_connect+0x1860/0x1860 ? rwlock_bug.part.0+0x90/0x90 cifs_readv_from_socket+0x479/0x690 cifs_read_from_socket+0x9d/0xe0 ? cifs_readv_from_socket+0x690/0x690 ? mempool_resize+0x690/0x690 ? rwlock_bug.part.0+0x90/0x90 ? memset+0x1f/0x40 ? allocate_buffers+0xff/0x340 cifs_demultiplex_thread+0x388/0x2a50 ? cifs_handle_standard+0x610/0x610 ? rcu_read_lock_held_common+0x120/0x120 ? mark_lock+0x11b/0xc00 ? __lock_acquire+0x14ed/0x3270 ? __kthread_parkme+0x78/0x100 ? lockdep_hardirqs_on+0x3e8/0x560 ? lock_downgrade+0x6a0/0x6a0 ? lockdep_hardirqs_on+0x3e8/0x560 ? _raw_spin_unlock_irqrestore+0x39/0x60 ? cifs_handle_standard+0x610/0x610 kthread+0x2bb/0x3a0 ? kthread_create_worker_on_cpu+0xc0/0xc0 ret_from_fork+0x3a/0x50 Allocated by task 649: save_stack+0x19/0x70 __kasan_kmalloc.constprop.5+0xa6/0xf0 kmem_cache_alloc+0x107/0x320 copy_process+0x17bc/0x5370 _do_fork+0x103/0xbf0 __x64_sys_clone+0x168/0x1e0 do_syscall_64+0x9b/0xec0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 0: save_stack+0x19/0x70 __kasan_slab_free+0x11d/0x160 kmem_cache_free+0xb5/0x3d0 rcu_core+0x52f/0x1230 __do_softirq+0x24d/0x962 The buggy address belongs to the object at ffff8880103e32c0 which belongs to the cache task_struct of size 6016 The buggy address is located 1960 bytes inside of 6016-byte region [ffff8880103e32c0, ffff8880103e4a40) The buggy address belongs to the page: page:ffffea000040f800 refcount:1 mapcount:0 mapping:ffff8880108da5c0 index:0xffff8880103e4c00 compound_mapcount: 0 raw: 4000000000010200 ffffea00001f2208 ffffea00001e3408 ffff8880108da5c0 raw: ffff8880103e4c00 0000000000050003 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880103e3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880103e3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880103e3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880103e3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880103e3b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== This can be reliably reproduced by adding the below delay to cifs_reconnect(), running find(1) on the mount, restarting the samba server while find is running, and killing find during the delay: spin_unlock(&GlobalMid_Lock); mutex_unlock(&server->srv_mutex); + msleep(10000); + cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__); list_for_each_safe(tmp, tmp2, &retry_list) { mid_entry = list_entry(tmp, struct mid_q_entry, qhead); Fix this by holding a reference to the task struct until the MID is freed. Signed-off-by: Vincent Whitchurch <[email protected]> Signed-off-by: Steve French <[email protected]> Reviewed-by: Paulo Alcantara (SUSE) <[email protected]> Reviewed-by: Pavel Shilovsky <[email protected]> [bwh: Backported to 3.16: - In _cifs_mid_q_entry_release(), use mid instead of midEntry - Adjust context, indentation] Signed-off-by: Ben Hutchings <[email protected]>
mdrjr
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Apr 15, 2024
[ Upstream commit 3d75b8a ] Always flush the per-vCPU async #PF workqueue when a vCPU is clearing its completion queue, e.g. when a VM and all its vCPUs is being destroyed. KVM must ensure that none of its workqueue callbacks is running when the last reference to the KVM _module_ is put. Gifting a reference to the associated VM prevents the workqueue callback from dereferencing freed vCPU/VM memory, but does not prevent the KVM module from being unloaded before the callback completes. Drop the misguided VM refcount gifting, as calling kvm_put_kvm() from async_pf_execute() if kvm_put_kvm() flushes the async #PF workqueue will result in deadlock. async_pf_execute() can't return until kvm_put_kvm() finishes, and kvm_put_kvm() can't return until async_pf_execute() finishes: WARNING: CPU: 8 PID: 251 at virt/kvm/kvm_main.c:1435 kvm_put_kvm+0x2d/0x320 [kvm] Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel kvm irqbypass CPU: 8 PID: 251 Comm: kworker/8:1 Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: events async_pf_execute [kvm] RIP: 0010:kvm_put_kvm+0x2d/0x320 [kvm] Call Trace: <TASK> async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> ---[ end trace 0000000000000000 ]--- INFO: task kworker/8:1:251 blocked for more than 120 seconds. Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/8:1 state:D stack:0 pid:251 ppid:2 flags:0x00004000 Workqueue: events async_pf_execute [kvm] Call Trace: <TASK> __schedule+0x33f/0xa40 schedule+0x53/0xc0 schedule_timeout+0x12a/0x140 __wait_for_common+0x8d/0x1d0 __flush_work.isra.0+0x19f/0x2c0 kvm_clear_async_pf_completion_queue+0x129/0x190 [kvm] kvm_arch_destroy_vm+0x78/0x1b0 [kvm] kvm_put_kvm+0x1c1/0x320 [kvm] async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> If kvm_clear_async_pf_completion_queue() actually flushes the workqueue, then there's no need to gift async_pf_execute() a reference because all invocations of async_pf_execute() will be forced to complete before the vCPU and its VM are destroyed/freed. And that in turn fixes the module unloading bug as __fput() won't do module_put() on the last vCPU reference until the vCPU has been freed, e.g. if closing the vCPU file also puts the last reference to the KVM module. Note that kvm_check_async_pf_completion() may also take the work item off the completion queue and so also needs to flush the work queue, as the work will not be seen by kvm_clear_async_pf_completion_queue(). Waiting on the workqueue could theoretically delay a vCPU due to waiting for the work to complete, but that's a very, very small chance, and likely a very small delay. kvm_arch_async_page_present_queued() unconditionally makes a new request, i.e. will effectively delay entering the guest, so the remaining work is really just: trace_kvm_async_pf_completed(addr, cr2_or_gpa); __kvm_vcpu_wake_up(vcpu); mmput(mm); and mmput() can't drop the last reference to the page tables if the vCPU is still alive, i.e. the vCPU won't get stuck tearing down page tables. Add a helper to do the flushing, specifically to deal with "wakeup all" work items, as they aren't actually work items, i.e. are never placed in a workqueue. Trying to flush a bogus workqueue entry rightly makes __flush_work() complain (kudos to whoever added that sanity check). Note, commit 5f6de5c ("KVM: Prevent module exit until all VMs are freed") *tried* to fix the module refcounting issue by having VMs grab a reference to the module, but that only made the bug slightly harder to hit as it gave async_pf_execute() a bit more time to complete before the KVM module could be unloaded. Fixes: af585b9 ("KVM: Halt vcpu if page it tries to access is swapped out") Cc: [email protected] Cc: David Matlack <[email protected]> Reviewed-by: Xu Yilun <[email protected]> Reviewed-by: Vitaly Kuznetsov <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
mdrjr
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May 7, 2024
[ Upstream commit 3d75b8a ] Always flush the per-vCPU async #PF workqueue when a vCPU is clearing its completion queue, e.g. when a VM and all its vCPUs is being destroyed. KVM must ensure that none of its workqueue callbacks is running when the last reference to the KVM _module_ is put. Gifting a reference to the associated VM prevents the workqueue callback from dereferencing freed vCPU/VM memory, but does not prevent the KVM module from being unloaded before the callback completes. Drop the misguided VM refcount gifting, as calling kvm_put_kvm() from async_pf_execute() if kvm_put_kvm() flushes the async #PF workqueue will result in deadlock. async_pf_execute() can't return until kvm_put_kvm() finishes, and kvm_put_kvm() can't return until async_pf_execute() finishes: WARNING: CPU: 8 PID: 251 at virt/kvm/kvm_main.c:1435 kvm_put_kvm+0x2d/0x320 [kvm] Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel kvm irqbypass CPU: 8 PID: 251 Comm: kworker/8:1 Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: events async_pf_execute [kvm] RIP: 0010:kvm_put_kvm+0x2d/0x320 [kvm] Call Trace: <TASK> async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> ---[ end trace 0000000000000000 ]--- INFO: task kworker/8:1:251 blocked for more than 120 seconds. Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/8:1 state:D stack:0 pid:251 ppid:2 flags:0x00004000 Workqueue: events async_pf_execute [kvm] Call Trace: <TASK> __schedule+0x33f/0xa40 schedule+0x53/0xc0 schedule_timeout+0x12a/0x140 __wait_for_common+0x8d/0x1d0 __flush_work.isra.0+0x19f/0x2c0 kvm_clear_async_pf_completion_queue+0x129/0x190 [kvm] kvm_arch_destroy_vm+0x78/0x1b0 [kvm] kvm_put_kvm+0x1c1/0x320 [kvm] async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> If kvm_clear_async_pf_completion_queue() actually flushes the workqueue, then there's no need to gift async_pf_execute() a reference because all invocations of async_pf_execute() will be forced to complete before the vCPU and its VM are destroyed/freed. And that in turn fixes the module unloading bug as __fput() won't do module_put() on the last vCPU reference until the vCPU has been freed, e.g. if closing the vCPU file also puts the last reference to the KVM module. Note that kvm_check_async_pf_completion() may also take the work item off the completion queue and so also needs to flush the work queue, as the work will not be seen by kvm_clear_async_pf_completion_queue(). Waiting on the workqueue could theoretically delay a vCPU due to waiting for the work to complete, but that's a very, very small chance, and likely a very small delay. kvm_arch_async_page_present_queued() unconditionally makes a new request, i.e. will effectively delay entering the guest, so the remaining work is really just: trace_kvm_async_pf_completed(addr, cr2_or_gpa); __kvm_vcpu_wake_up(vcpu); mmput(mm); and mmput() can't drop the last reference to the page tables if the vCPU is still alive, i.e. the vCPU won't get stuck tearing down page tables. Add a helper to do the flushing, specifically to deal with "wakeup all" work items, as they aren't actually work items, i.e. are never placed in a workqueue. Trying to flush a bogus workqueue entry rightly makes __flush_work() complain (kudos to whoever added that sanity check). Note, commit 5f6de5c ("KVM: Prevent module exit until all VMs are freed") *tried* to fix the module refcounting issue by having VMs grab a reference to the module, but that only made the bug slightly harder to hit as it gave async_pf_execute() a bit more time to complete before the KVM module could be unloaded. Fixes: af585b9 ("KVM: Halt vcpu if page it tries to access is swapped out") Cc: [email protected] Cc: David Matlack <[email protected]> Reviewed-by: Xu Yilun <[email protected]> Reviewed-by: Vitaly Kuznetsov <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Sean Christopherson <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
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Enable TUN device module, needed by openvpn, etc.