Damon/next #3

goldhorn · 2021-03-22T06:26:30Z

No description provided.

Patch series "Rationalise __alloc_pages wrappers", v3. I was poking around the __alloc_pages variants trying to understand why they each exist, and couldn't really find a good justification for keeping __alloc_pages and __alloc_pages_nodemask as separate functions. That led to getting rid of alloc_pages_current() and then I noticed the documentation was bad, and then I noticed the mempolicy documentation wasn't included. Anyway, this is all cleanups & doc fixes. This patch (of 7): We have two masks involved -- the nodemask and the gfp mask, so alloc_mask is an unclear name. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Shorten some overly-long lines by renaming this identifier. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Mike Rapoport <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

There are only two callers of __alloc_pages() so prune the thicket of alloc_page variants by combining the two functions together. Current callers of __alloc_pages() simply add an extra 'NULL' parameter and current callers of __alloc_pages_nodemask() call __alloc_pages() instead. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Mike Rapoport <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

When CONFIG_NUMA is enabled, alloc_pages() is a wrapper around alloc_pages_current(). This is pointless, just implement alloc_pages() directly. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Mike Rapoport <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Document alloc_pages() for both NUMA and non-NUMA cases as kernel-doc doesn't care. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Acked-by: Mike Rapoport <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

The current formatting doesn't quite work with kernel-doc. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Acked-by: Mike Rapoport <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Sphinx interprets the Return section as a list and complains about it. Turn it into a sentence and move it to the end of the kernel-doc to fit the kernel-doc style. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> Acked-by: Mike Rapoport <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Currently, debugging CMA allocation failures is quite limited. The most common source of these failures seems to be page migration which doesn't provide any useful information on the reason of the failure by itself. alloc_contig_range can report those failures as it holds a list of migrate-failed pages. The information logged by dump_page() has already proven helpful for debugging allocation issues, like identifying long-term pinnings on ZONE_MOVABLE or MIGRATE_CMA. Let's use the dynamic debugging infrastructure, such that we avoid flooding the logs and creating a lot of noise on frequent alloc_contig_range() calls. This information is helpful for debugging only. There are two ifdefery conditions to support common dyndbg options: - CONFIG_DYNAMIC_DEBUG_CORE && DYNAMIC_DEBUG_MODULE It aims for supporting the feature with only specific file with adding ccflags. - CONFIG_DYNAMIC_DEBUG It aims for supporting the feature with system wide globally. A simple example to enable the feature: Admin could enable the dump like this(by default, disabled) echo "func alloc_contig_dump_pages +p" > control Admin could disable it. echo "func alloc_contig_dump_pages =_" > control Detail goes Documentation/admin-guide/dynamic-debug-howto.rst A concern is utility functions in dump_page use inconsistent loglevels. In the future, we might want to make the loglevels used inside dump_page() consistent and eventually rework the way we log the information here. See [1]. [1] https://lore.kernel.org/linux-mm/[email protected]/ Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Minchan Kim <[email protected]> Reviewed-by: David Hildenbrand <[email protected]> Cc: John Dias <[email protected]> Cc: Michal Hocko <[email protected]> Cc: David Hildenbrand <[email protected]> Cc: Jason Baron <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Commit 214496c ("ia64: make SPARSEMEM default and disable DISCONTIGMEM") removed the last enabler of ARCH_DISCONTIGMEM_DEFAULT, hence the memory model can no longer default to DISCONTIGMEM_MANUAL. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Geert Uytterhoeven <[email protected]> Reviewed-by: Mike Rapoport <[email protected]> Reviewed-by: David Hildenbrand <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Patch series "hugetlb: Disable huge pmd unshare for uffd-wp", v4. This series tries to disable huge pmd unshare of hugetlbfs backed memory for uffd-wp. Although uffd-wp of hugetlbfs is still during rfc stage, the idea of this series may be needed for multiple tasks (Axel's uffd minor fault series, and Mike's soft dirty series), so I picked it out from the larger series. This patch (of 4): It is a preparation work to be able to behave differently in the per architecture huge_pte_alloc() according to different VMA attributes. Pass it deeper into huge_pmd_share() so that we can avoid the find_vma() call. Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Peter Xu <[email protected]> Suggested-by: Mike Kravetz <[email protected]> Cc: Adam Ruprecht <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Axel Rasmussen <[email protected]> Cc: Cannon Matthews <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chinwen Chang <[email protected]> Cc: David Rientjes <[email protected]> Cc: "Dr . David Alan Gilbert" <[email protected]> Cc: Huang Ying <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jann Horn <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Lokesh Gidra <[email protected]> Cc: "Matthew Wilcox (Oracle)" <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: "Michal Koutn" <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Mina Almasry <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Oliver Upton <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Shawn Anastasio <[email protected]> Cc: Steven Price <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

build fix Link: https://lkml.kernel.org/r/20210304164653.GB397383@xz-x1 Signed-off-by: Andrew Morton <[email protected]>

Huge pmd sharing could bring problem to userfaultfd. The thing is that userfaultfd is running its logic based on the special bits on page table entries, however the huge pmd sharing could potentially share page table entries for different address ranges. That could cause issues on either: - When sharing huge pmd page tables for an uffd write protected range, the newly mapped huge pmd range will also be write protected unexpectedly, or, - When we try to write protect a range of huge pmd shared range, we'll first do huge_pmd_unshare() in hugetlb_change_protection(), however that also means the UFFDIO_WRITEPROTECT could be silently skipped for the shared region, which could lead to data loss. Since at it, a few other things are done altogether: - Move want_pmd_share() from mm/hugetlb.c into linux/hugetlb.h, because that's definitely something that arch code would like to use too - ARM64 currently directly check against CONFIG_ARCH_WANT_HUGE_PMD_SHARE when trying to share huge pmd. Switch to the want_pmd_share() helper. Since at it, move vma_shareable() from huge_pmd_share() into want_pmd_share(). Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Peter Xu <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Reviewed-by: Axel Rasmussen <[email protected]> Cc: Adam Ruprecht <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Cannon Matthews <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chinwen Chang <[email protected]> Cc: David Rientjes <[email protected]> Cc: "Dr . David Alan Gilbert" <[email protected]> Cc: Huang Ying <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jann Horn <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Lokesh Gidra <[email protected]> Cc: "Matthew Wilcox (Oracle)" <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: "Michal Koutn" <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Mina Almasry <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Oliver Upton <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Shawn Anastasio <[email protected]> Cc: Steven Price <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

want_pmd_share() is undefined with !ARCH_WANT_HUGE_PMD_SHARE since it's put by accident into a "#ifdef ARCH_WANT_HUGE_PMD_SHARE" block. Moving it out won't work either since vma_shareable() is only defined within the block. Define it for !ARCH_WANT_HUGE_PMD_SHARE instead. Link: https://lkml.kernel.org/r/[email protected] Fixes: 5b109cc1cdcc ("hugetlb/userfaultfd: forbid huge pmd sharing when uffd enabled") Signed-off-by: Peter Xu <[email protected]> Reported-by: Naresh Kamboju <[email protected]> Tested-by: Naresh Kamboju <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Cc: Axel Rasmussen <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Prepare for it to be called outside of mm/hugetlb.c. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Peter Xu <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Reviewed-by: Axel Rasmussen <[email protected]> Cc: Adam Ruprecht <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Cannon Matthews <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chinwen Chang <[email protected]> Cc: David Rientjes <[email protected]> Cc: "Dr . David Alan Gilbert" <[email protected]> Cc: Huang Ying <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jann Horn <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Lokesh Gidra <[email protected]> Cc: "Matthew Wilcox (Oracle)" <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: "Michal Koutn" <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Mina Almasry <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Oliver Upton <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Shawn Anastasio <[email protected]> Cc: Steven Price <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Huge pmd sharing for hugetlbfs is racy with userfaultfd-wp because userfaultfd-wp is always based on pgtable entries, so they cannot be shared. Walk the hugetlb range and unshare all such mappings if there is, right before UFFDIO_REGISTER will succeed and return to userspace. This will pair with want_pmd_share() in hugetlb code so that huge pmd sharing is completely disabled for userfaultfd-wp registered range. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Peter Xu <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Cc: Peter Xu <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Axel Rasmussen <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Matthew Wilcox (Oracle) <[email protected]> Cc: Adam Ruprecht <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Cannon Matthews <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chinwen Chang <[email protected]> Cc: David Rientjes <[email protected]> Cc: "Dr . David Alan Gilbert" <[email protected]> Cc: Huang Ying <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jann Horn <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: Lokesh Gidra <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: "Michal Koutn" <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Mina Almasry <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Oliver Upton <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Shawn Anastasio <[email protected]> Cc: Steven Price <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…e_page() vma_resv_map(vma) checks if a reserve map is associated with the vma. The routine vma_needs_reservation() will check vma_resv_map(vma) and return 1 if no reserv map is present. map_chg is set to the return value of vma_needs_reservation(). Therefore, !vma_resv_map(vma) is redundant in the expression: map_chg || avoid_reserve || !vma_resv_map(vma); Remove the redundant check. [Thanks Mike Kravetz for reshaping this commit message!] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

HUGETLB_PAGE_SIZE_VARIABLE need not be defined for each individual platform subscribing it. Instead just make it generic. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Anshuman Khandual <[email protected]> Suggested-by: Christoph Hellwig <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Acked-by: Michael Ellerman <[email protected]> [powerpc] Cc: Benjamin Herrenschmidt <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Christophe Leroy <[email protected]> Cc: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Patch series "Some cleanups for hugetlb". This series contains cleanups to remove unnecessary VM_BUG_ON_PAGE, use helper function and so on. I also collect some previous patches into this series in case they are forgotten. This patch (of 5): We could use pages_per_huge_page to get the number of pages per hugepage, use get_hstate_idx to calculate hstate index, and use hstate_is_gigantic to check if a hstate is gigantic to make code more succinct. Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…state() We should not transfer the per-node surplus state when we do not cross the node in order to save some cpu cycles Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…p_migrate() !PageHuge(oldhpage) is implicitly checked in page_hstate() above, so we remove this explicit one. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Cc: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…b_no_page() Rework the error handling code when alloc_huge_page() failed to remove some duplicated code and simplify the code slightly. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Cc: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

The fault_mutex hashing overhead can be avoided in truncate_op case because page faults can not race with truncation in this routine. So calculate hash for fault_mutex only in !truncate_op case to save some cpu cycles. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Cc: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…apped_thps() Patch series "Cleanup and fixup for khugepaged", v2. This series contains cleanups to remove unneeded return value, use helper function and so on. And there is one fix to correct the wrong result value for trace_mm_collapse_huge_page_isolate(). This patch (of 4): The return value of khugepaged_collapse_pte_mapped_thps() is never checked since it's introduced. We should remove such unneeded return value. Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Acked-by: Kirill A. Shutemov <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Ebru Akagunduz <[email protected]> Cc: Dan Carpenter <[email protected]> Cc: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

smp_wmb() is needed to avoid the copy_huge_page writes to become visible after the set_pmd_at() write here. But we can reuse the smp_wmb() inside __SetPageUptodate() to remove this redundant one. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Acked-by: Kirill A. Shutemov <[email protected]> Cc: Dan Carpenter <[email protected]> Cc: Ebru Akagunduz <[email protected]> Cc: Mike Kravetz <[email protected]> Cc: Rik van Riel <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Commit 4d45e75 ("mm: remove the now-unnecessary mmget_still_valid() hack") have made khugepaged_test_exit() suitable for check mm->mm_users against 0. Use this helper here. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Acked-by: Kirill A. Shutemov <[email protected]> Cc: Dan Carpenter <[email protected]> Cc: Ebru Akagunduz <[email protected]> Cc: Mike Kravetz <[email protected]> Cc: Rik van Riel <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…olate() In writable and !referenced case, the result value should be SCAN_LACK_REFERENCED_PAGE for trace_mm_collapse_huge_page_isolate() instead of default 0 (SCAN_FAIL) here. Link: https://lkml.kernel.org/r/[email protected] Fixes: 7d2eba0 ("mm: add tracepoint for scanning pages") Signed-off-by: Miaohe Lin <[email protected]> Acked-by: Kirill A. Shutemov <[email protected]> Cc: Dan Carpenter <[email protected]> Cc: Ebru Akagunduz <[email protected]> Cc: Mike Kravetz <[email protected]> Cc: Rik van Riel <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

There is no need to use a new local variable ret2 to get the return value of handle_userfault(). Use ret directly to make code more succinct. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Reviewed-by: Andrew Morton <[email protected]> Cc: Mike Kravetz <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

We do not have a direct user interface of splitting the compound page backing a THP and there is no need unless we want to expose the THP implementation details to users. Make <debugfs>/split_huge_pages accept a new command to do that. By writing "<pid>,<vaddr_start>,<vaddr_end>" to <debugfs>/split_huge_pages, THPs within the given virtual address range from the process with the given pid are split. It is used to test split_huge_page function. In addition, a selftest program is added to tools/testing/selftests/vm to utilize the interface by splitting PMD THPs and PTE-mapped THPs. This does not change the old behavior, i.e., writing 1 to the interface to split all THPs in the system. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Zi Yan <[email protected]> Cc: "Kirill A . Shutemov" <[email protected]> Cc: Shuah Khan <[email protected]> Cc: John Hubbard <[email protected]> Cc: Sandipan Das <[email protected]> Cc: David Hildenbrand <[email protected]> Cc: Yang Shi <[email protected]> Cc: Mika Penttila <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Patch series "userfaultfd: add minor fault handling", v9. Overview ======== This series adds a new userfaultfd feature, UFFD_FEATURE_MINOR_HUGETLBFS. When enabled (via the UFFDIO_API ioctl), this feature means that any hugetlbfs VMAs registered with UFFDIO_REGISTER_MODE_MISSING will *also* get events for "minor" faults. By "minor" fault, I mean the following situation: Let there exist two mappings (i.e., VMAs) to the same page(s) (shared memory). One of the mappings is registered with userfaultfd (in minor mode), and the other is not. Via the non-UFFD mapping, the underlying pages have already been allocated & filled with some contents. The UFFD mapping has not yet been faulted in; when it is touched for the first time, this results in what I'm calling a "minor" fault. As a concrete example, when working with hugetlbfs, we have huge_pte_none(), but find_lock_page() finds an existing page. We also add a new ioctl to resolve such faults: UFFDIO_CONTINUE. The idea is, userspace resolves the fault by either a) doing nothing if the contents are already correct, or b) updating the underlying contents using the second, non-UFFD mapping (via memcpy/memset or similar, or something fancier like RDMA, or etc...). In either case, userspace issues UFFDIO_CONTINUE to tell the kernel "I have ensured the page contents are correct, carry on setting up the mapping". Use Case ======== Consider the use case of VM live migration (e.g. under QEMU/KVM): 1. While a VM is still running, we copy the contents of its memory to a target machine. The pages are populated on the target by writing to the non-UFFD mapping, using the setup described above. The VM is still running (and therefore its memory is likely changing), so this may be repeated several times, until we decide the target is "up to date enough". 2. We pause the VM on the source, and start executing on the target machine. During this gap, the VM's user(s) will *see* a pause, so it is desirable to minimize this window. 3. Between the last time any page was copied from the source to the target, and when the VM was paused, the contents of that page may have changed - and therefore the copy we have on the target machine is out of date. Although we can keep track of which pages are out of date, for VMs with large amounts of memory, it is "slow" to transfer this information to the target machine. We want to resume execution before such a transfer would complete. 4. So, the guest begins executing on the target machine. The first time it touches its memory (via the UFFD-registered mapping), userspace wants to intercept this fault. Userspace checks whether or not the page is up to date, and if not, copies the updated page from the source machine, via the non-UFFD mapping. Finally, whether a copy was performed or not, userspace issues a UFFDIO_CONTINUE ioctl to tell the kernel "I have ensured the page contents are correct, carry on setting up the mapping". We don't have to do all of the final updates on-demand. The userfaultfd manager can, in the background, also copy over updated pages once it receives the map of which pages are up-to-date or not. Interaction with Existing APIs ============================== Because this is a feature, a registered VMA could potentially receive both missing and minor faults. I spent some time thinking through how the existing API interacts with the new feature: UFFDIO_CONTINUE cannot be used to resolve non-minor faults, as it does not allocate a new page. If UFFDIO_CONTINUE is used on a non-minor fault: - For non-shared memory or shmem, -EINVAL is returned. - For hugetlb, -EFAULT is returned. UFFDIO_COPY and UFFDIO_ZEROPAGE cannot be used to resolve minor faults. Without modifications, the existing codepath assumes a new page needs to be allocated. This is okay, since userspace must have a second non-UFFD-registered mapping anyway, thus there isn't much reason to want to use these in any case (just memcpy or memset or similar). - If UFFDIO_COPY is used on a minor fault, -EEXIST is returned. - If UFFDIO_ZEROPAGE is used on a minor fault, -EEXIST is returned (or -EINVAL in the case of hugetlb, as UFFDIO_ZEROPAGE is unsupported in any case). - UFFDIO_WRITEPROTECT simply doesn't work with shared memory, and returns -ENOENT in that case (regardless of the kind of fault). Future Work =========== This series only supports hugetlbfs. I have a second series in flight to support shmem as well, extending the functionality. This series is more mature than the shmem support at this point, and the functionality works fully on hugetlbfs, so this series can be merged first and then shmem support will follow. This patch (of 6): This feature allows userspace to intercept "minor" faults. By "minor" faults, I mean the following situation: Let there exist two mappings (i.e., VMAs) to the same page(s). One of the mappings is registered with userfaultfd (in minor mode), and the other is not. Via the non-UFFD mapping, the underlying pages have already been allocated & filled with some contents. The UFFD mapping has not yet been faulted in; when it is touched for the first time, this results in what I'm calling a "minor" fault. As a concrete example, when working with hugetlbfs, we have huge_pte_none(), but find_lock_page() finds an existing page. This commit adds the new registration mode, and sets the relevant flag on the VMAs being registered. In the hugetlb fault path, if we find that we have huge_pte_none(), but find_lock_page() does indeed find an existing page, then we have a "minor" fault, and if the VMA has the userfaultfd registration flag, we call into userfaultfd to handle it. This is implemented as a new registration mode, instead of an API feature. This is because the alternative implementation has significant drawbacks [1]. However, doing it this was requires we allocate a VM_* flag for the new registration mode. On 32-bit systems, there are no unused bits, so this feature is only supported on architectures with CONFIG_ARCH_USES_HIGH_VMA_FLAGS. When attempting to register a VMA in MINOR mode on 32-bit architectures, we return -EINVAL. [1] https://lore.kernel.org/patchwork/patch/1380226/ Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Axel Rasmussen <[email protected]> Reviewed-by: Peter Xu <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chinwen Chang <[email protected]> Cc: Huang Ying <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jann Horn <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: Lokesh Gidra <[email protected]> Cc: "Matthew Wilcox (Oracle)" <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: "Michal Koutn" <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Mike Kravetz <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Peter Xu <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Shawn Anastasio <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Steven Price <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Adam Ruprecht <[email protected]> Cc: Axel Rasmussen <[email protected]> Cc: Cannon Matthews <[email protected]> Cc: "Dr . David Alan Gilbert" <[email protected]> Cc: David Rientjes <[email protected]> Cc: Mina Almasry <[email protected]> Cc: Oliver Upton <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

As the comment says: for the MINOR fault use case, although the page might be present and populated in the other (non-UFFD-registered) half of the mapping, it may be out of date, and we explicitly want userspace to get a minor fault so it can check and potentially update the page's contents. Huge PMD sharing would prevent these faults from occurring for suitably aligned areas, so disable it upon UFFD registration. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Axel Rasmussen <[email protected]> Reviewed-by: Peter Xu <[email protected]> Reviewed-by: Mike Kravetz <[email protected]> Cc: Adam Ruprecht <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: Cannon Matthews <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chinwen Chang <[email protected]> Cc: David Rientjes <[email protected]> Cc: "Dr . David Alan Gilbert" <[email protected]> Cc: Huang Ying <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jann Horn <[email protected]> Cc: Jerome Glisse <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Lokesh Gidra <[email protected]> Cc: "Matthew Wilcox (Oracle)" <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: "Michal Koutn" <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Mina Almasry <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Oliver Upton <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Shawn Anastasio <[email protected]> Cc: Steven Price <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

We found a timeout problem with the pldm command on our system. The reason is that the MCTP-I3C driver has a race condition when receiving multiple-packet messages in multi-thread, resulting in a wrong packet order problem. We identified this problem by adding a debug message to the mctp_i3c_read function. According to the MCTP spec, a multiple-packet message must be composed in sequence, and if there is a wrong sequence, the whole message will be discarded and wait for the next SOM. For example, SOM → Pkt Seq #2 → Pkt Seq #1 → Pkt Seq #3 → EOM. Therefore, we try to solve this problem by adding a mutex to the mctp_i3c_read function. Before the modification, when a command requesting a multiple-packet message response is sent consecutively, an error usually occurs within 100 loops. After the mutex, it can go through 40000 loops without any error, and it seems to run well. Fixes: c8755b2 ("mctp i3c: MCTP I3C driver") Signed-off-by: Leo Yang <[email protected]> Link: https://patch.msgid.link/[email protected] [[email protected]: dropped already answered question from changelog] Signed-off-by: Paolo Abeni <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

If GuC fails to load, the driver wedges, but in the process it tries to do stuff that may not be initialized yet. This moves the xe_gt_tlb_invalidation_init() to be done earlier: as its own doc says, it's a software-only initialization and should had been named with the _early() suffix. Move it to be called by xe_gt_init_early(), so the locks and seqno are initialized, avoiding a NULL ptr deref when wedging: xe 0000:03:00.0: [drm] *ERROR* GT0: load failed: status: Reset = 0, BootROM = 0x50, UKernel = 0x00, MIA = 0x00, Auth = 0x01 xe 0000:03:00.0: [drm] *ERROR* GT0: firmware signature verification failed xe 0000:03:00.0: [drm] *ERROR* CRITICAL: Xe has declared device 0000:03:00.0 as wedged. ... BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 9 UID: 0 PID: 3908 Comm: modprobe Tainted: G U W 6.13.0-rc4-xe+ #3 Tainted: [U]=USER, [W]=WARN Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-S ADP-S DDR5 UDIMM CRB, BIOS ADLSFWI1.R00.3275.A00.2207010640 07/01/2022 RIP: 0010:xe_gt_tlb_invalidation_reset+0x75/0x110 [xe] This can be easily triggered by poking the GuC binary to force a signature failure. There will still be an extra message, xe 0000:03:00.0: [drm] *ERROR* GT0: GuC mmio request 0x4100: no reply 0x4100 but that's better than a NULL ptr deref. Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/3956 Fixes: c9474b7 ("drm/xe: Wedge the entire device") Reviewed-by: Matthew Brost <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] Signed-off-by: Lucas De Marchi <[email protected]> (cherry picked from commit 5001ef3) Signed-off-by: Thomas Hellström <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

…ux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 changes for 6.13, part #3 - Always check page state in hyp_ack_unshare() - Align set_id_regs selftest with the fact that ASIDBITS field is RO - Various vPMU fixes for bugs that only affect nested virt

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Fix a lockdep warning [1] observed during the write combining test. The warning indicates a potential nested lock scenario that could lead to a deadlock. However, this is a false positive alarm because the SF lock and its parent lock are distinct ones. The lockdep confusion arises because the locks belong to the same object class (i.e., struct mlx5_core_dev). To resolve this, the code has been refactored to avoid taking both locks. Instead, only the parent lock is acquired. [1] raw_ethernet_bw/2118 is trying to acquire lock: [ 213.619032] ffff88811dd75e08 (&dev->wc_state_lock){+.+.}-{3:3}, at: mlx5_wc_support_get+0x18c/0x210 [mlx5_core] [ 213.620270] [ 213.620270] but task is already holding lock: [ 213.620943] ffff88810b585e08 (&dev->wc_state_lock){+.+.}-{3:3}, at: mlx5_wc_support_get+0x10c/0x210 [mlx5_core] [ 213.622045] [ 213.622045] other info that might help us debug this: [ 213.622778] Possible unsafe locking scenario: [ 213.622778] [ 213.623465] CPU0 [ 213.623815] ---- [ 213.624148] lock(&dev->wc_state_lock); [ 213.624615] lock(&dev->wc_state_lock); [ 213.625071] [ 213.625071] *** DEADLOCK *** [ 213.625071] [ 213.625805] May be due to missing lock nesting notation [ 213.625805] [ 213.626522] 4 locks held by raw_ethernet_bw/2118: [ 213.627019] #0: ffff88813f80d578 (&uverbs_dev->disassociate_srcu){.+.+}-{0:0}, at: ib_uverbs_ioctl+0xc4/0x170 [ib_uverbs] [ 213.628088] #1: ffff88810fb23930 (&file->hw_destroy_rwsem){.+.+}-{3:3}, at: ib_init_ucontext+0x2d/0xf0 [ib_uverbs] [ 213.629094] #2: ffff88810fb23878 (&file->ucontext_lock){+.+.}-{3:3}, at: ib_init_ucontext+0x49/0xf0 [ib_uverbs] [ 213.630106] #3: ffff88810b585e08 (&dev->wc_state_lock){+.+.}-{3:3}, at: mlx5_wc_support_get+0x10c/0x210 [mlx5_core] [ 213.631185] [ 213.631185] stack backtrace: [ 213.631718] CPU: 1 UID: 0 PID: 2118 Comm: raw_ethernet_bw Not tainted 6.12.0-rc7_internal_net_next_mlx5_89a0ad0 #1 [ 213.632722] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 213.633785] Call Trace: [ 213.634099] [ 213.634393] dump_stack_lvl+0x7e/0xc0 [ 213.634806] print_deadlock_bug+0x278/0x3c0 [ 213.635265] __lock_acquire+0x15f4/0x2c40 [ 213.635712] lock_acquire+0xcd/0x2d0 [ 213.636120] ? mlx5_wc_support_get+0x18c/0x210 [mlx5_core] [ 213.636722] ? mlx5_ib_enable_lb+0x24/0xa0 [mlx5_ib] [ 213.637277] __mutex_lock+0x81/0xda0 [ 213.637697] ? mlx5_wc_support_get+0x18c/0x210 [mlx5_core] [ 213.638305] ? mlx5_wc_support_get+0x18c/0x210 [mlx5_core] [ 213.638902] ? rcu_read_lock_sched_held+0x3f/0x70 [ 213.639400] ? mlx5_wc_support_get+0x18c/0x210 [mlx5_core] [ 213.640016] mlx5_wc_support_get+0x18c/0x210 [mlx5_core] [ 213.640615] set_ucontext_resp+0x68/0x2b0 [mlx5_ib] [ 213.641144] ? debug_mutex_init+0x33/0x40 [ 213.641586] mlx5_ib_alloc_ucontext+0x18e/0x7b0 [mlx5_ib] [ 213.642145] ib_init_ucontext+0xa0/0xf0 [ib_uverbs] [ 213.642679] ib_uverbs_handler_UVERBS_METHOD_GET_CONTEXT+0x95/0xc0 [ib_uverbs] [ 213.643426] ? _copy_from_user+0x46/0x80 [ 213.643878] ib_uverbs_cmd_verbs+0xa6b/0xc80 [ib_uverbs] [ 213.644426] ? ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x130/0x130 [ib_uverbs] [ 213.645213] ? __lock_acquire+0xa99/0x2c40 [ 213.645675] ? lock_acquire+0xcd/0x2d0 [ 213.646101] ? ib_uverbs_ioctl+0xc4/0x170 [ib_uverbs] [ 213.646625] ? reacquire_held_locks+0xcf/0x1f0 [ 213.647102] ? do_user_addr_fault+0x45d/0x770 [ 213.647586] ib_uverbs_ioctl+0xe0/0x170 [ib_uverbs] [ 213.648102] ? ib_uverbs_ioctl+0xc4/0x170 [ib_uverbs] [ 213.648632] __x64_sys_ioctl+0x4d3/0xaa0 [ 213.649060] ? do_user_addr_fault+0x4a8/0x770 [ 213.649528] do_syscall_64+0x6d/0x140 [ 213.649947] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 213.650478] RIP: 0033:0x7fa179b0737b [ 213.650893] Code: ff ff ff 85 c0 79 9b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 7d 2a 0f 00 f7 d8 64 89 01 48 [ 213.652619] RSP: 002b:00007ffd2e6d46e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 213.653390] RAX: ffffffffffffffda RBX: 00007ffd2e6d47f8 RCX: 00007fa179b0737b [ 213.654084] RDX: 00007ffd2e6d47e0 RSI: 00000000c0181b01 RDI: 0000000000000003 [ 213.654767] RBP: 00007ffd2e6d47c0 R08: 00007fa1799be010 R09: 0000000000000002 [ 213.655453] R10: 00007ffd2e6d4960 R11: 0000000000000246 R12: 00007ffd2e6d487c [ 213.656170] R13: 0000000000000027 R14: 0000000000000001 R15: 00007ffd2e6d4f70 Fixes: d98995b ("net/mlx5: Reimplement write combining test") Signed-off-by: Yishai Hadas <[email protected]> Reviewed-by: Michael Guralnik <[email protected]> Reviewed-by: Larysa Zaremba <[email protected]> Signed-off-by: Tariq Toukan <[email protected]> Signed-off-by: Paolo Abeni <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

This commit addresses a circular locking dependency issue within the GFX isolation mechanism. The problem was identified by a warning indicating a potential deadlock due to inconsistent lock acquisition order. - The `amdgpu_gfx_enforce_isolation_ring_begin_use` and `amdgpu_gfx_enforce_isolation_ring_end_use` functions previously acquired `enforce_isolation_mutex` and called `amdgpu_gfx_kfd_sch_ctrl`, leading to potential deadlocks. ie., If `amdgpu_gfx_kfd_sch_ctrl` is called while `enforce_isolation_mutex` is held, and `amdgpu_gfx_enforce_isolation_handler` is called while `kfd_sch_mutex` is held, it can create a circular dependency. By ensuring consistent lock usage, this fix resolves the issue: [ 606.297333] ====================================================== [ 606.297343] WARNING: possible circular locking dependency detected [ 606.297353] 6.10.0-amd-mlkd-610-311224-lof #19 Tainted: G OE [ 606.297365] ------------------------------------------------------ [ 606.297375] kworker/u96:3/3825 is trying to acquire lock: [ 606.297385] ffff9aa64e431cb8 ((work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work)){+.+.}-{0:0}, at: __flush_work+0x232/0x610 [ 606.297413] but task is already holding lock: [ 606.297423] ffff9aa64e432338 (&adev->gfx.kfd_sch_mutex){+.+.}-{3:3}, at: amdgpu_gfx_kfd_sch_ctrl+0x51/0x4d0 [amdgpu] [ 606.297725] which lock already depends on the new lock. [ 606.297738] the existing dependency chain (in reverse order) is: [ 606.297749] -> #2 (&adev->gfx.kfd_sch_mutex){+.+.}-{3:3}: [ 606.297765] __mutex_lock+0x85/0x930 [ 606.297776] mutex_lock_nested+0x1b/0x30 [ 606.297786] amdgpu_gfx_kfd_sch_ctrl+0x51/0x4d0 [amdgpu] [ 606.298007] amdgpu_gfx_enforce_isolation_ring_begin_use+0x2a4/0x5d0 [amdgpu] [ 606.298225] amdgpu_ring_alloc+0x48/0x70 [amdgpu] [ 606.298412] amdgpu_ib_schedule+0x176/0x8a0 [amdgpu] [ 606.298603] amdgpu_job_run+0xac/0x1e0 [amdgpu] [ 606.298866] drm_sched_run_job_work+0x24f/0x430 [gpu_sched] [ 606.298880] process_one_work+0x21e/0x680 [ 606.298890] worker_thread+0x190/0x350 [ 606.298899] kthread+0xe7/0x120 [ 606.298908] ret_from_fork+0x3c/0x60 [ 606.298919] ret_from_fork_asm+0x1a/0x30 [ 606.298929] -> #1 (&adev->enforce_isolation_mutex){+.+.}-{3:3}: [ 606.298947] __mutex_lock+0x85/0x930 [ 606.298956] mutex_lock_nested+0x1b/0x30 [ 606.298966] amdgpu_gfx_enforce_isolation_handler+0x87/0x370 [amdgpu] [ 606.299190] process_one_work+0x21e/0x680 [ 606.299199] worker_thread+0x190/0x350 [ 606.299208] kthread+0xe7/0x120 [ 606.299217] ret_from_fork+0x3c/0x60 [ 606.299227] ret_from_fork_asm+0x1a/0x30 [ 606.299236] -> #0 ((work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work)){+.+.}-{0:0}: [ 606.299257] __lock_acquire+0x16f9/0x2810 [ 606.299267] lock_acquire+0xd1/0x300 [ 606.299276] __flush_work+0x250/0x610 [ 606.299286] cancel_delayed_work_sync+0x71/0x80 [ 606.299296] amdgpu_gfx_kfd_sch_ctrl+0x287/0x4d0 [amdgpu] [ 606.299509] amdgpu_gfx_enforce_isolation_ring_begin_use+0x2a4/0x5d0 [amdgpu] [ 606.299723] amdgpu_ring_alloc+0x48/0x70 [amdgpu] [ 606.299909] amdgpu_ib_schedule+0x176/0x8a0 [amdgpu] [ 606.300101] amdgpu_job_run+0xac/0x1e0 [amdgpu] [ 606.300355] drm_sched_run_job_work+0x24f/0x430 [gpu_sched] [ 606.300369] process_one_work+0x21e/0x680 [ 606.300378] worker_thread+0x190/0x350 [ 606.300387] kthread+0xe7/0x120 [ 606.300396] ret_from_fork+0x3c/0x60 [ 606.300406] ret_from_fork_asm+0x1a/0x30 [ 606.300416] other info that might help us debug this: [ 606.300428] Chain exists of: (work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work) --> &adev->enforce_isolation_mutex --> &adev->gfx.kfd_sch_mutex [ 606.300458] Possible unsafe locking scenario: [ 606.300468] CPU0 CPU1 [ 606.300476] ---- ---- [ 606.300484] lock(&adev->gfx.kfd_sch_mutex); [ 606.300494] lock(&adev->enforce_isolation_mutex); [ 606.300508] lock(&adev->gfx.kfd_sch_mutex); [ 606.300521] lock((work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work)); [ 606.300536] *** DEADLOCK *** [ 606.300546] 5 locks held by kworker/u96:3/3825: [ 606.300555] #0: ffff9aa5aa1f5d58 ((wq_completion)comp_1.1.0){+.+.}-{0:0}, at: process_one_work+0x3f5/0x680 [ 606.300577] #1: ffffaa53c3c97e40 ((work_completion)(&sched->work_run_job)){+.+.}-{0:0}, at: process_one_work+0x1d6/0x680 [ 606.300600] #2: ffff9aa64e463c98 (&adev->enforce_isolation_mutex){+.+.}-{3:3}, at: amdgpu_gfx_enforce_isolation_ring_begin_use+0x1c3/0x5d0 [amdgpu] [ 606.300837] #3: ffff9aa64e432338 (&adev->gfx.kfd_sch_mutex){+.+.}-{3:3}, at: amdgpu_gfx_kfd_sch_ctrl+0x51/0x4d0 [amdgpu] [ 606.301062] #4: ffffffff8c1a5660 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x70/0x610 [ 606.301083] stack backtrace: [ 606.301092] CPU: 14 PID: 3825 Comm: kworker/u96:3 Tainted: G OE 6.10.0-amd-mlkd-610-311224-lof #19 [ 606.301109] Hardware name: Gigabyte Technology Co., Ltd. X570S GAMING X/X570S GAMING X, BIOS F7 03/22/2024 [ 606.301124] Workqueue: comp_1.1.0 drm_sched_run_job_work [gpu_sched] [ 606.301140] Call Trace: [ 606.301146] <TASK> [ 606.301154] dump_stack_lvl+0x9b/0xf0 [ 606.301166] dump_stack+0x10/0x20 [ 606.301175] print_circular_bug+0x26c/0x340 [ 606.301187] check_noncircular+0x157/0x170 [ 606.301197] ? register_lock_class+0x48/0x490 [ 606.301213] __lock_acquire+0x16f9/0x2810 [ 606.301230] lock_acquire+0xd1/0x300 [ 606.301239] ? __flush_work+0x232/0x610 [ 606.301250] ? srso_alias_return_thunk+0x5/0xfbef5 [ 606.301261] ? mark_held_locks+0x54/0x90 [ 606.301274] ? __flush_work+0x232/0x610 [ 606.301284] __flush_work+0x250/0x610 [ 606.301293] ? __flush_work+0x232/0x610 [ 606.301305] ? __pfx_wq_barrier_func+0x10/0x10 [ 606.301318] ? mark_held_locks+0x54/0x90 [ 606.301331] ? srso_alias_return_thunk+0x5/0xfbef5 [ 606.301345] cancel_delayed_work_sync+0x71/0x80 [ 606.301356] amdgpu_gfx_kfd_sch_ctrl+0x287/0x4d0 [amdgpu] [ 606.301661] amdgpu_gfx_enforce_isolation_ring_begin_use+0x2a4/0x5d0 [amdgpu] [ 606.302050] ? srso_alias_return_thunk+0x5/0xfbef5 [ 606.302069] amdgpu_ring_alloc+0x48/0x70 [amdgpu] [ 606.302452] amdgpu_ib_schedule+0x176/0x8a0 [amdgpu] [ 606.302862] ? drm_sched_entity_error+0x82/0x190 [gpu_sched] [ 606.302890] amdgpu_job_run+0xac/0x1e0 [amdgpu] [ 606.303366] drm_sched_run_job_work+0x24f/0x430 [gpu_sched] [ 606.303388] process_one_work+0x21e/0x680 [ 606.303409] worker_thread+0x190/0x350 [ 606.303424] ? __pfx_worker_thread+0x10/0x10 [ 606.303437] kthread+0xe7/0x120 [ 606.303449] ? __pfx_kthread+0x10/0x10 [ 606.303463] ret_from_fork+0x3c/0x60 [ 606.303476] ? __pfx_kthread+0x10/0x10 [ 606.303489] ret_from_fork_asm+0x1a/0x30 [ 606.303512] </TASK> v2: Refactor lock handling to resolve circular dependency (Alex) - Introduced a `sched_work` flag to defer the call to `amdgpu_gfx_kfd_sch_ctrl` until after releasing `enforce_isolation_mutex`. - This change ensures that `amdgpu_gfx_kfd_sch_ctrl` is called outside the critical section, preventing the circular dependency and deadlock. - The `sched_work` flag is set within the mutex-protected section if conditions are met, and the actual function call is made afterward. - This approach ensures consistent lock acquisition order. Fixes: afefd6f ("drm/amdgpu: Implement Enforce Isolation Handler for KGD/KFD serialization") Cc: Christian König <[email protected]> Cc: Alex Deucher <[email protected]> Signed-off-by: Srinivasan Shanmugam <[email protected]> Suggested-by: Alex Deucher <[email protected]> Reviewed-by: Alex Deucher <[email protected]> Signed-off-by: Alex Deucher <[email protected]> (cherry picked from commit 0b6b2dd) Cc: [email protected]

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

irq_chip functions may be called in raw spinlock context. Therefore, we must also use a raw spinlock for our own internal locking. This fixes the following lockdep splat: [ 5.349336] ============================= [ 5.353349] [ BUG: Invalid wait context ] [ 5.357361] 6.13.0-rc5+ #69 Tainted: G W [ 5.363031] ----------------------------- [ 5.367045] kworker/u17:1/44 is trying to lock: [ 5.371587] ffffff88018b02c0 (&chip->gpio_lock){....}-{3:3}, at: xgpio_irq_unmask (drivers/gpio/gpio-xilinx.c:433 (discriminator 8)) [ 5.380079] other info that might help us debug this: [ 5.385138] context-{5:5} [ 5.387762] 5 locks held by kworker/u17:1/44: [ 5.392123] #0: ffffff8800014958 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work (kernel/workqueue.c:3204) [ 5.402260] #1: ffffffc082fcbdd8 (deferred_probe_work){+.+.}-{0:0}, at: process_one_work (kernel/workqueue.c:3205) [ 5.411528] #2: ffffff880172c900 (&dev->mutex){....}-{4:4}, at: __device_attach (drivers/base/dd.c:1006) [ 5.419929] #3: ffffff88039c8268 (request_class#2){+.+.}-{4:4}, at: __setup_irq (kernel/irq/internals.h:156 kernel/irq/manage.c:1596) [ 5.428331] #4: ffffff88039c80c8 (lock_class#2){....}-{2:2}, at: __setup_irq (kernel/irq/manage.c:1614) [ 5.436472] stack backtrace: [ 5.439359] CPU: 2 UID: 0 PID: 44 Comm: kworker/u17:1 Tainted: G W 6.13.0-rc5+ #69 [ 5.448690] Tainted: [W]=WARN [ 5.451656] Hardware name: xlnx,zynqmp (DT) [ 5.455845] Workqueue: events_unbound deferred_probe_work_func [ 5.461699] Call trace: [ 5.464147] show_stack+0x18/0x24 C [ 5.467821] dump_stack_lvl (lib/dump_stack.c:123) [ 5.471501] dump_stack (lib/dump_stack.c:130) [ 5.474824] __lock_acquire (kernel/locking/lockdep.c:4828 kernel/locking/lockdep.c:4898 kernel/locking/lockdep.c:5176) [ 5.478758] lock_acquire (arch/arm64/include/asm/percpu.h:40 kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851 kernel/locking/lockdep.c:5814) [ 5.482429] _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:111 kernel/locking/spinlock.c:162) [ 5.486797] xgpio_irq_unmask (drivers/gpio/gpio-xilinx.c:433 (discriminator 8)) [ 5.490737] irq_enable (kernel/irq/internals.h:236 kernel/irq/chip.c:170 kernel/irq/chip.c:439 kernel/irq/chip.c:432 kernel/irq/chip.c:345) [ 5.494060] __irq_startup (kernel/irq/internals.h:241 kernel/irq/chip.c:180 kernel/irq/chip.c:250) [ 5.497645] irq_startup (kernel/irq/chip.c:270) [ 5.501143] __setup_irq (kernel/irq/manage.c:1807) [ 5.504728] request_threaded_irq (kernel/irq/manage.c:2208) Fixes: a32c7ca ("gpio: gpio-xilinx: Add interrupt support") Signed-off-by: Sean Anderson <[email protected]> Cc: [email protected] Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Bartosz Golaszewski <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

This commit addresses a circular locking dependency issue within the GFX isolation mechanism. The problem was identified by a warning indicating a potential deadlock due to inconsistent lock acquisition order. - The `amdgpu_gfx_enforce_isolation_ring_begin_use` and `amdgpu_gfx_enforce_isolation_ring_end_use` functions previously acquired `enforce_isolation_mutex` and called `amdgpu_gfx_kfd_sch_ctrl`, leading to potential deadlocks. ie., If `amdgpu_gfx_kfd_sch_ctrl` is called while `enforce_isolation_mutex` is held, and `amdgpu_gfx_enforce_isolation_handler` is called while `kfd_sch_mutex` is held, it can create a circular dependency. By ensuring consistent lock usage, this fix resolves the issue: [ 606.297333] ====================================================== [ 606.297343] WARNING: possible circular locking dependency detected [ 606.297353] 6.10.0-amd-mlkd-610-311224-lof #19 Tainted: G OE [ 606.297365] ------------------------------------------------------ [ 606.297375] kworker/u96:3/3825 is trying to acquire lock: [ 606.297385] ffff9aa64e431cb8 ((work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work)){+.+.}-{0:0}, at: __flush_work+0x232/0x610 [ 606.297413] but task is already holding lock: [ 606.297423] ffff9aa64e432338 (&adev->gfx.kfd_sch_mutex){+.+.}-{3:3}, at: amdgpu_gfx_kfd_sch_ctrl+0x51/0x4d0 [amdgpu] [ 606.297725] which lock already depends on the new lock. [ 606.297738] the existing dependency chain (in reverse order) is: [ 606.297749] -> #2 (&adev->gfx.kfd_sch_mutex){+.+.}-{3:3}: [ 606.297765] __mutex_lock+0x85/0x930 [ 606.297776] mutex_lock_nested+0x1b/0x30 [ 606.297786] amdgpu_gfx_kfd_sch_ctrl+0x51/0x4d0 [amdgpu] [ 606.298007] amdgpu_gfx_enforce_isolation_ring_begin_use+0x2a4/0x5d0 [amdgpu] [ 606.298225] amdgpu_ring_alloc+0x48/0x70 [amdgpu] [ 606.298412] amdgpu_ib_schedule+0x176/0x8a0 [amdgpu] [ 606.298603] amdgpu_job_run+0xac/0x1e0 [amdgpu] [ 606.298866] drm_sched_run_job_work+0x24f/0x430 [gpu_sched] [ 606.298880] process_one_work+0x21e/0x680 [ 606.298890] worker_thread+0x190/0x350 [ 606.298899] kthread+0xe7/0x120 [ 606.298908] ret_from_fork+0x3c/0x60 [ 606.298919] ret_from_fork_asm+0x1a/0x30 [ 606.298929] -> #1 (&adev->enforce_isolation_mutex){+.+.}-{3:3}: [ 606.298947] __mutex_lock+0x85/0x930 [ 606.298956] mutex_lock_nested+0x1b/0x30 [ 606.298966] amdgpu_gfx_enforce_isolation_handler+0x87/0x370 [amdgpu] [ 606.299190] process_one_work+0x21e/0x680 [ 606.299199] worker_thread+0x190/0x350 [ 606.299208] kthread+0xe7/0x120 [ 606.299217] ret_from_fork+0x3c/0x60 [ 606.299227] ret_from_fork_asm+0x1a/0x30 [ 606.299236] -> #0 ((work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work)){+.+.}-{0:0}: [ 606.299257] __lock_acquire+0x16f9/0x2810 [ 606.299267] lock_acquire+0xd1/0x300 [ 606.299276] __flush_work+0x250/0x610 [ 606.299286] cancel_delayed_work_sync+0x71/0x80 [ 606.299296] amdgpu_gfx_kfd_sch_ctrl+0x287/0x4d0 [amdgpu] [ 606.299509] amdgpu_gfx_enforce_isolation_ring_begin_use+0x2a4/0x5d0 [amdgpu] [ 606.299723] amdgpu_ring_alloc+0x48/0x70 [amdgpu] [ 606.299909] amdgpu_ib_schedule+0x176/0x8a0 [amdgpu] [ 606.300101] amdgpu_job_run+0xac/0x1e0 [amdgpu] [ 606.300355] drm_sched_run_job_work+0x24f/0x430 [gpu_sched] [ 606.300369] process_one_work+0x21e/0x680 [ 606.300378] worker_thread+0x190/0x350 [ 606.300387] kthread+0xe7/0x120 [ 606.300396] ret_from_fork+0x3c/0x60 [ 606.300406] ret_from_fork_asm+0x1a/0x30 [ 606.300416] other info that might help us debug this: [ 606.300428] Chain exists of: (work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work) --> &adev->enforce_isolation_mutex --> &adev->gfx.kfd_sch_mutex [ 606.300458] Possible unsafe locking scenario: [ 606.300468] CPU0 CPU1 [ 606.300476] ---- ---- [ 606.300484] lock(&adev->gfx.kfd_sch_mutex); [ 606.300494] lock(&adev->enforce_isolation_mutex); [ 606.300508] lock(&adev->gfx.kfd_sch_mutex); [ 606.300521] lock((work_completion)(&(&adev->gfx.enforce_isolation[i].work)->work)); [ 606.300536] *** DEADLOCK *** [ 606.300546] 5 locks held by kworker/u96:3/3825: [ 606.300555] #0: ffff9aa5aa1f5d58 ((wq_completion)comp_1.1.0){+.+.}-{0:0}, at: process_one_work+0x3f5/0x680 [ 606.300577] #1: ffffaa53c3c97e40 ((work_completion)(&sched->work_run_job)){+.+.}-{0:0}, at: process_one_work+0x1d6/0x680 [ 606.300600] #2: ffff9aa64e463c98 (&adev->enforce_isolation_mutex){+.+.}-{3:3}, at: amdgpu_gfx_enforce_isolation_ring_begin_use+0x1c3/0x5d0 [amdgpu] [ 606.300837] #3: ffff9aa64e432338 (&adev->gfx.kfd_sch_mutex){+.+.}-{3:3}, at: amdgpu_gfx_kfd_sch_ctrl+0x51/0x4d0 [amdgpu] [ 606.301062] #4: ffffffff8c1a5660 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x70/0x610 [ 606.301083] stack backtrace: [ 606.301092] CPU: 14 PID: 3825 Comm: kworker/u96:3 Tainted: G OE 6.10.0-amd-mlkd-610-311224-lof #19 [ 606.301109] Hardware name: Gigabyte Technology Co., Ltd. X570S GAMING X/X570S GAMING X, BIOS F7 03/22/2024 [ 606.301124] Workqueue: comp_1.1.0 drm_sched_run_job_work [gpu_sched] [ 606.301140] Call Trace: [ 606.301146] <TASK> [ 606.301154] dump_stack_lvl+0x9b/0xf0 [ 606.301166] dump_stack+0x10/0x20 [ 606.301175] print_circular_bug+0x26c/0x340 [ 606.301187] check_noncircular+0x157/0x170 [ 606.301197] ? register_lock_class+0x48/0x490 [ 606.301213] __lock_acquire+0x16f9/0x2810 [ 606.301230] lock_acquire+0xd1/0x300 [ 606.301239] ? __flush_work+0x232/0x610 [ 606.301250] ? srso_alias_return_thunk+0x5/0xfbef5 [ 606.301261] ? mark_held_locks+0x54/0x90 [ 606.301274] ? __flush_work+0x232/0x610 [ 606.301284] __flush_work+0x250/0x610 [ 606.301293] ? __flush_work+0x232/0x610 [ 606.301305] ? __pfx_wq_barrier_func+0x10/0x10 [ 606.301318] ? mark_held_locks+0x54/0x90 [ 606.301331] ? srso_alias_return_thunk+0x5/0xfbef5 [ 606.301345] cancel_delayed_work_sync+0x71/0x80 [ 606.301356] amdgpu_gfx_kfd_sch_ctrl+0x287/0x4d0 [amdgpu] [ 606.301661] amdgpu_gfx_enforce_isolation_ring_begin_use+0x2a4/0x5d0 [amdgpu] [ 606.302050] ? srso_alias_return_thunk+0x5/0xfbef5 [ 606.302069] amdgpu_ring_alloc+0x48/0x70 [amdgpu] [ 606.302452] amdgpu_ib_schedule+0x176/0x8a0 [amdgpu] [ 606.302862] ? drm_sched_entity_error+0x82/0x190 [gpu_sched] [ 606.302890] amdgpu_job_run+0xac/0x1e0 [amdgpu] [ 606.303366] drm_sched_run_job_work+0x24f/0x430 [gpu_sched] [ 606.303388] process_one_work+0x21e/0x680 [ 606.303409] worker_thread+0x190/0x350 [ 606.303424] ? __pfx_worker_thread+0x10/0x10 [ 606.303437] kthread+0xe7/0x120 [ 606.303449] ? __pfx_kthread+0x10/0x10 [ 606.303463] ret_from_fork+0x3c/0x60 [ 606.303476] ? __pfx_kthread+0x10/0x10 [ 606.303489] ret_from_fork_asm+0x1a/0x30 [ 606.303512] </TASK> v2: Refactor lock handling to resolve circular dependency (Alex) - Introduced a `sched_work` flag to defer the call to `amdgpu_gfx_kfd_sch_ctrl` until after releasing `enforce_isolation_mutex`. - This change ensures that `amdgpu_gfx_kfd_sch_ctrl` is called outside the critical section, preventing the circular dependency and deadlock. - The `sched_work` flag is set within the mutex-protected section if conditions are met, and the actual function call is made afterward. - This approach ensures consistent lock acquisition order. Fixes: afefd6f ("drm/amdgpu: Implement Enforce Isolation Handler for KGD/KFD serialization") Cc: Christian König <[email protected]> Cc: Alex Deucher <[email protected]> Signed-off-by: Srinivasan Shanmugam <[email protected]> Suggested-by: Alex Deucher <[email protected]> Reviewed-by: Alex Deucher <[email protected]> Signed-off-by: Alex Deucher <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Packets handled by hardware have added secpath as a way to inform XFRM core code that this path was already handled. That secpath is not needed at all after policy is checked and it is removed later in the stack. However, in the case of IP forwarding is enabled (/proc/sys/net/ipv4/ip_forward), that secpath is not removed and packets which already were handled are reentered to the driver TX path with xfrm_offload set. The following kernel panic is observed in mlx5 in such case: mlx5_core 0000:04:00.0 enp4s0f0np0: Link up mlx5_core 0000:04:00.1 enp4s0f1np1: Link up Initializing XFRM netlink socket IPsec XFRM device driver BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 0 P4D 0 Oops: Oops: 0010 [#1] PREEMPT SMP CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc1-alex #3 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0018:ffffb87380003800 EFLAGS: 00010206 RAX: ffff8df004e02600 RBX: ffffb873800038d8 RCX: 00000000ffff98cf RDX: ffff8df00733e108 RSI: ffff8df00521fb80 RDI: ffff8df001661f00 RBP: ffffb87380003850 R08: ffff8df013980000 R09: 0000000000000010 R10: 0000000000000002 R11: 0000000000000002 R12: ffff8df001661f00 R13: ffff8df00521fb80 R14: ffff8df00733e108 R15: ffff8df011faf04e FS: 0000000000000000(0000) GS:ffff8df46b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000106384000 CR4: 0000000000350ef0 Call Trace: <IRQ> ? show_regs+0x63/0x70 ? __die_body+0x20/0x60 ? __die+0x2b/0x40 ? page_fault_oops+0x15c/0x550 ? do_user_addr_fault+0x3ed/0x870 ? exc_page_fault+0x7f/0x190 ? asm_exc_page_fault+0x27/0x30 mlx5e_ipsec_handle_tx_skb+0xe7/0x2f0 [mlx5_core] mlx5e_xmit+0x58e/0x1980 [mlx5_core] ? __fib_lookup+0x6a/0xb0 dev_hard_start_xmit+0x82/0x1d0 sch_direct_xmit+0xfe/0x390 __dev_queue_xmit+0x6d8/0xee0 ? __fib_lookup+0x6a/0xb0 ? internal_add_timer+0x48/0x70 ? mod_timer+0xe2/0x2b0 neigh_resolve_output+0x115/0x1b0 __neigh_update+0x26a/0xc50 neigh_update+0x14/0x20 arp_process+0x2cb/0x8e0 ? __napi_build_skb+0x5e/0x70 arp_rcv+0x11e/0x1c0 ? dev_gro_receive+0x574/0x820 __netif_receive_skb_list_core+0x1cf/0x1f0 netif_receive_skb_list_internal+0x183/0x2a0 napi_complete_done+0x76/0x1c0 mlx5e_napi_poll+0x234/0x7a0 [mlx5_core] __napi_poll+0x2d/0x1f0 net_rx_action+0x1a6/0x370 ? atomic_notifier_call_chain+0x3b/0x50 ? irq_int_handler+0x15/0x20 [mlx5_core] handle_softirqs+0xb9/0x2f0 ? handle_irq_event+0x44/0x60 irq_exit_rcu+0xdb/0x100 common_interrupt+0x98/0xc0 </IRQ> <TASK> asm_common_interrupt+0x27/0x40 RIP: 0010:pv_native_safe_halt+0xb/0x10 Code: 09 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 0f 22 0f 1f 84 00 00 00 00 00 90 eb 07 0f 00 2d 7f e9 36 00 fb 40 00 83 ff 07 77 21 89 ff ff 24 fd 88 3d a1 bd 0f 21 f8 RSP: 0018:ffffffffbe603de8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000f92f46680 RDX: 0000000000000037 RSI: 00000000ffffffff RDI: 00000000000518d4 RBP: ffffffffbe603df0 R08: 000000cd42e4dffb R09: ffffffffbe603d70 R10: 0000004d80d62680 R11: 0000000000000001 R12: ffffffffbe60bf40 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffffbe60aff8 ? default_idle+0x9/0x20 arch_cpu_idle+0x9/0x10 default_idle_call+0x29/0xf0 do_idle+0x1f2/0x240 cpu_startup_entry+0x2c/0x30 rest_init+0xe7/0x100 start_kernel+0x76b/0xb90 x86_64_start_reservations+0x18/0x30 x86_64_start_kernel+0xc0/0x110 ? setup_ghcb+0xe/0x130 common_startup_64+0x13e/0x141 </TASK> Modules linked in: esp4_offload esp4 xfrm_interface xfrm6_tunnel tunnel4 tunnel6 xfrm_user xfrm_algo binfmt_misc intel_rapl_msr intel_rapl_common kvm_amd ccp kvm input_leds serio_raw qemu_fw_cfg sch_fq_codel dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua efi_pstore ip_tables x_tables autofs4 raid10 raid456 async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx libcrc32c raid1 raid0 mlx5_core crct10dif_pclmul crc32_pclmul polyval_clmulni polyval_generic ghash_clmulni_intel sha256_ssse3 sha1_ssse3 ahci mlxfw i2c_i801 libahci i2c_mux i2c_smbus psample virtio_rng pci_hyperv_intf aesni_intel crypto_simd cryptd CR2: 0000000000000000 ---[ end trace 0000000000000000 ]--- RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0018:ffffb87380003800 EFLAGS: 00010206 RAX: ffff8df004e02600 RBX: ffffb873800038d8 RCX: 00000000ffff98cf RDX: ffff8df00733e108 RSI: ffff8df00521fb80 RDI: ffff8df001661f00 RBP: ffffb87380003850 R08: ffff8df013980000 R09: 0000000000000010 R10: 0000000000000002 R11: 0000000000000002 R12: ffff8df001661f00 R13: ffff8df00521fb80 R14: ffff8df00733e108 R15: ffff8df011faf04e FS: 0000000000000000(0000) GS:ffff8df46b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000106384000 CR4: 0000000000350ef0 Kernel panic - not syncing: Fatal exception in interrupt Kernel Offset: 0x3b800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- Fixes: 5958372 ("xfrm: add RX datapath protection for IPsec packet offload mode") Signed-off-by: Alexandre Cassen <[email protected]> Signed-off-by: Leon Romanovsky <[email protected]> Signed-off-by: Steffen Klassert <[email protected]>

libtraceevent parses and returns an array of argument fields, sometimes larger than RAW_SYSCALL_ARGS_NUM (6) because it includes "__syscall_nr", idx will traverse to index 6 (7th element) whereas sc->fmt->arg holds 6 elements max, creating an out-of-bounds access. This runtime error is found by UBsan. The error message: $ sudo UBSAN_OPTIONS=print_stacktrace=1 ./perf trace -a --max-events=1 builtin-trace.c:1966:35: runtime error: index 6 out of bounds for type 'syscall_arg_fmt [6]' #0 0x5c04956be5fe in syscall__alloc_arg_fmts /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:1966 #1 0x5c04956c0510 in trace__read_syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2110 #2 0x5c04956c372b in trace__syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2436 #3 0x5c04956d2f39 in trace__init_syscalls_bpf_prog_array_maps /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:3897 #4 0x5c04956d6d25 in trace__run /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:4335 #5 0x5c04956e112e in cmd_trace /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:5502 #6 0x5c04956eda7d in run_builtin /home/howard/hw/linux-perf/tools/perf/perf.c:351 #7 0x5c04956ee0a8 in handle_internal_command /home/howard/hw/linux-perf/tools/perf/perf.c:404 #8 0x5c04956ee37f in run_argv /home/howard/hw/linux-perf/tools/perf/perf.c:448 #9 0x5c04956ee8e9 in main /home/howard/hw/linux-perf/tools/perf/perf.c:556 #10 0x79eb3622a3b7 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #11 0x79eb3622a47a in __libc_start_main_impl ../csu/libc-start.c:360 #12 0x5c04955422d4 in _start (/home/howard/hw/linux-perf/tools/perf/perf+0x4e02d4) (BuildId: 5b6cab2d59e96a4341741765ad6914a4d784dbc6) 0.000 ( 0.014 ms): Chrome_ChildIO/117244 write(fd: 238, buf: !, count: 1) = 1 Fixes: 5e58fcf ("perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint") Signed-off-by: Howard Chu <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Namhyung Kim <[email protected]>

This fixes the following hard lockup in isolate_lru_folios() during memory reclaim. If the LRU mostly contains ineligible folios this may trigger watchdog. watchdog: Watchdog detected hard LOCKUP on cpu 173 RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0 Call Trace: _raw_spin_lock_irqsave+0x31/0x40 folio_lruvec_lock_irqsave+0x5f/0x90 folio_batch_move_lru+0x91/0x150 lru_add_drain_per_cpu+0x1c/0x40 process_one_work+0x17d/0x350 worker_thread+0x27b/0x3a0 kthread+0xe8/0x120 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1b/0x30 lruvec->lru_lock owner： PID: 2865 TASK: ffff888139214d40 CPU: 40 COMMAND: "kswapd0" #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde [exception RIP: isolate_lru_folios+403] RIP: ffffffffa597df53 RSP: ffffc90006fb7c28 RFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffc90006fb7c60 RCX: ffffea04a2196f88 RDX: ffffc90006fb7c60 RSI: ffffc90006fb7c60 RDI: ffffea04a2197048 RBP: ffff88812cbd3010 R8: ffffea04a2197008 R9: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea04a2197008 R13: ffffea04a2197048 R14: ffffc90006fb7de8 R15: 0000000003e3e937 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 <NMI exception stack> #5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 #6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788 #7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0 #8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354 #9 [ffffc90006fb7ef8] kthread at ffffffffa5748238 crash> Scenario: User processe are requesting a large amount of memory and keep page active. Then a module continuously requests memory from ZONE_DMA32 area. Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached. However pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. Reproduce: Terminal 1: Construct to continuously increase pages active(anon). mkdir /tmp/memory mount -t tmpfs -o size=1024000M tmpfs /tmp/memory dd if=/dev/zero of=/tmp/memory/block bs=4M tail /tmp/memory/block Terminal 2: vmstat -a 1 active will increase. procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ... r b swpd free inact active si so bi bo 1 0 0 1445623076 45898836 83646008 0 0 0 1 0 0 1445623076 43450228 86094616 0 0 0 1 0 0 1445623076 41003480 88541364 0 0 0 1 0 0 1445623076 38557088 90987756 0 0 0 1 0 0 1445623076 36109688 93435156 0 0 0 1 0 0 1445619552 33663256 95881632 0 0 0 1 0 0 1445619804 31217140 98327792 0 0 0 1 0 0 1445619804 28769988 100774944 0 0 0 1 0 0 1445619804 26322348 103222584 0 0 0 1 0 0 1445619804 23875592 105669340 0 0 0 cat /proc/meminfo | head Active(anon) increase. MemTotal: 1579941036 kB MemFree: 1445618500 kB MemAvailable: 1453013224 kB Buffers: 6516 kB Cached: 128653956 kB SwapCached: 0 kB Active: 118110812 kB Inactive: 11436620 kB Active(anon): 115345744 kB Inactive(anon): 945292 kB When the Active(anon) is 115345744 kB, insmod module triggers the ZONE_DMA32 watermark. perf record -e vmscan:mm_vmscan_lru_isolate -aR perf script isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2 nr_skipped=2 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844 nr_skipped=28835844 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29 nr_skipped=29 nr_taken=0 lru=active_anon isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0 nr_skipped=0 nr_taken=0 lru=active_anon See nr_scanned=28835844. 28835844 * 4k = 115343376KB approximately equal to 115345744 kB. If increase Active(anon) to 1000G then insmod module triggers the ZONE_DMA32 watermark. hard lockup will occur. In my device nr_scanned = 0000000003e3e937 when hard lockup. Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB. [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53 ffffc90006fb7c30: 0000000000000020 0000000000000000 ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000 ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8 ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48 ffffc90006fb7c70: 0000000000000000 0000000000000000 ffffc90006fb7c80: 0000000000000000 0000000000000000 ffffc90006fb7c90: 0000000000000000 0000000000000000 ffffc90006fb7ca0: 0000000000000000 0000000003e3e937 ffffc90006fb7cb0: 0000000000000000 0000000000000000 ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000 About the Fixes: Why did it take eight years to be discovered? The problem requires the following conditions to occur: 1. The device memory should be large enough. 2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area. 3. The memory in ZONE_DMA32 needs to reach the watermark. If the memory is not large enough, or if the usage design of ZONE_DMA32 area memory is reasonable, this problem is difficult to detect. notes: The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL, but other suitable scenarios may also trigger the problem. Link: https://lkml.kernel.org/r/[email protected] Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis") Signed-off-by: liuye <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Yang Shi <[email protected]> Signed-off-by: Andrew Morton <[email protected]>

Matthew Wilcox (Oracle) and others added 30 commits March 18, 2021 02:03

hugetlb-pass-vma-into-huge_pte_alloc-and-huge_pmd_share-fix

55933df

build fix Link: https://lkml.kernel.org/r/20210304164653.GB397383@xz-x1 Signed-off-by: Andrew Morton <[email protected]>

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