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2024-11-27Revert "fs: don't block i_writecount during exec"Christian Brauner1-8/+15
This reverts commit 2a010c41285345da60cece35575b4e0af7e7bf44. Rui Ueyama <rui314@gmail.com> writes: > I'm the creator and the maintainer of the mold linker > (https://github.com/rui314/mold). Recently, we discovered that mold > started causing process crashes in certain situations due to a change > in the Linux kernel. Here are the details: > > - In general, overwriting an existing file is much faster than > creating an empty file and writing to it on Linux, so mold attempts to > reuse an existing executable file if it exists. > > - If a program is running, opening the executable file for writing > previously failed with ETXTBSY. If that happens, mold falls back to > creating a new file. > > - However, the Linux kernel recently changed the behavior so that > writing to an executable file is now always permitted > (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2a010c412853). > > That caused mold to write to an executable file even if there's a > process running that file. Since changes to mmap'ed files are > immediately visible to other processes, any processes running that > file would almost certainly crash in a very mysterious way. > Identifying the cause of these random crashes took us a few days. > > Rejecting writes to an executable file that is currently running is a > well-known behavior, and Linux had operated that way for a very long > time. So, I don’t believe relying on this behavior was our mistake; > rather, I see this as a regression in the Linux kernel. Quoting myself from commit 2a010c412853 ("fs: don't block i_writecount during exec") > Yes, someone in userspace could potentially be relying on this. It's not > completely out of the realm of possibility but let's find out if that's > actually the case and not guess. It seems we found out that someone is relying on this obscure behavior. So revert the change. Link: https://github.com/rui314/mold/issues/1361 Link: https://lore.kernel.org/r/4a2bc207-76be-4715-8e12-7fc45a76a125@leemhuis.info Cc: <stable@vger.kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-11-25Merge tag 'mm-nonmm-stable-2024-11-24-02-05' of ↵Linus Torvalds1-10/+0
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - The series "resource: A couple of cleanups" from Andy Shevchenko performs some cleanups in the resource management code - The series "Improve the copy of task comm" from Yafang Shao addresses possible race-induced overflows in the management of task_struct.comm[] - The series "Remove unnecessary header includes from {tools/}lib/list_sort.c" from Kuan-Wei Chiu adds some cleanups and a small fix to the list_sort library code and to its selftest - The series "Enhance min heap API with non-inline functions and optimizations" also from Kuan-Wei Chiu optimizes and cleans up the min_heap library code - The series "nilfs2: Finish folio conversion" from Ryusuke Konishi finishes off nilfs2's folioification - The series "add detect count for hung tasks" from Lance Yang adds more userspace visibility into the hung-task detector's activity - Apart from that, singelton patches in many places - please see the individual changelogs for details * tag 'mm-nonmm-stable-2024-11-24-02-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits) gdb: lx-symbols: do not error out on monolithic build kernel/reboot: replace sprintf() with sysfs_emit() lib: util_macros_kunit: add kunit test for util_macros.h util_macros.h: fix/rework find_closest() macros Improve consistency of '#error' directive messages ocfs2: fix uninitialized value in ocfs2_file_read_iter() hung_task: add docs for hung_task_detect_count hung_task: add detect count for hung tasks dma-buf: use atomic64_inc_return() in dma_buf_getfile() fs/proc/kcore.c: fix coccinelle reported ERROR instances resource: avoid unnecessary resource tree walking in __region_intersects() ocfs2: remove unused errmsg function and table ocfs2: cluster: fix a typo lib/scatterlist: use sg_phys() helper checkpatch: always parse orig_commit in fixes tag nilfs2: convert metadata aops from writepage to writepages nilfs2: convert nilfs_recovery_copy_block() to take a folio nilfs2: convert nilfs_page_count_clean_buffers() to take a folio nilfs2: remove nilfs_writepage nilfs2: convert checkpoint file to be folio-based ...
2024-11-05get rid of __get_task_comm()Yafang Shao1-10/+0
Patch series "Improve the copy of task comm", v8. Using {memcpy,strncpy,strcpy,kstrdup} to copy the task comm relies on the length of task comm. Changes in the task comm could result in a destination string that is overflow. Therefore, we should explicitly ensure the destination string is always NUL-terminated, regardless of the task comm. This approach will facilitate future extensions to the task comm. As suggested by Linus [0], we can identify all relevant code with the following git grep command: git grep 'memcpy.*->comm\>' git grep 'kstrdup.*->comm\>' git grep 'strncpy.*->comm\>' git grep 'strcpy.*->comm\>' PATCH #2~#4: memcpy PATCH #5~#6: kstrdup PATCH #7: strcpy Please note that strncpy() is not included in this series as it is being tracked by another effort. [1] This patch (of 7): We want to eliminate the use of __get_task_comm() for the following reasons: - The task_lock() is unnecessary Quoted from Linus [0]: : Since user space can randomly change their names anyway, using locking : was always wrong for readers (for writers it probably does make sense : to have some lock - although practically speaking nobody cares there : either, but at least for a writer some kind of race could have : long-term mixed results Link: https://lkml.kernel.org/r/20241007144911.27693-1-laoar.shao@gmail.com Link: https://lkml.kernel.org/r/20241007144911.27693-2-laoar.shao@gmail.com Link: https://lore.kernel.org/all/CAHk-=wivfrF0_zvf+oj6==Sh=-npJooP8chLPEfaFV0oNYTTBA@mail.gmail.com [0] Link: https://lore.kernel.org/all/CAHk-=whWtUC-AjmGJveAETKOMeMFSTwKwu99v7+b6AyHMmaDFA@mail.gmail.com/ Link: https://lore.kernel.org/all/CAHk-=wjAmmHUg6vho1KjzQi2=psR30+CogFd4aXrThr2gsiS4g@mail.gmail.com/ [0] Link: https://github.com/KSPP/linux/issues/90 [1] Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Matus Jokay <matus.jokay@stuba.sk> Cc: Alejandro Colomar <alx@kernel.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Maxime Ripard <mripard@kernel.org> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Quentin Monnet <qmo@kernel.org> Cc: Simon Horman <horms@kernel.org> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Cc: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-14sched: Improve cache locality of RSEQ concurrency IDs for intermittent workloadsMathieu Desnoyers1-1/+1
commit 223baf9d17f25 ("sched: Fix performance regression introduced by mm_cid") introduced a per-mm/cpu current concurrency id (mm_cid), which keeps a reference to the concurrency id allocated for each CPU. This reference expires shortly after a 100ms delay. These per-CPU references keep the per-mm-cid data cache-local in situations where threads are running at least once on each CPU within each 100ms window, thus keeping the per-cpu reference alive. However, intermittent workloads behaving in bursts spaced by more than 100ms on each CPU exhibit bad cache locality and degraded performance compared to purely per-cpu data indexing, because concurrency IDs are allocated over various CPUs and cores, therefore losing cache locality of the associated data. Introduce the following changes to improve per-mm-cid cache locality: - Add a "recent_cid" field to the per-mm/cpu mm_cid structure to keep track of which mm_cid value was last used, and use it as a hint to attempt re-allocating the same concurrency ID the next time this mm/cpu needs to allocate a concurrency ID, - Add a per-mm CPUs allowed mask, which keeps track of the union of CPUs allowed for all threads belonging to this mm. This cpumask is only set during the lifetime of the mm, never cleared, so it represents the union of all the CPUs allowed since the beginning of the mm lifetime (note that the mm_cpumask() is really arch-specific and tailored to the TLB flush needs, and is thus _not_ a viable approach for this), - Add a per-mm nr_cpus_allowed to keep track of the weight of the per-mm CPUs allowed mask (for fast access), - Add a per-mm max_nr_cid to keep track of the highest number of concurrency IDs allocated for the mm. This is used for expanding the concurrency ID allocation within the upper bound defined by: min(mm->nr_cpus_allowed, mm->mm_users) When the next unused CID value reaches this threshold, stop trying to expand the cid allocation and use the first available cid value instead. Spreading allocation to use all the cid values within the range [ 0, min(mm->nr_cpus_allowed, mm->mm_users) - 1 ] improves cache locality while preserving mm_cid compactness within the expected user limits, - In __mm_cid_try_get, only return cid values within the range [ 0, mm->nr_cpus_allowed ] rather than [ 0, nr_cpu_ids ]. This prevents allocating cids above the number of allowed cpus in rare scenarios where cid allocation races with a concurrent remote-clear of the per-mm/cpu cid. This improvement is made possible by the addition of the per-mm CPUs allowed mask, - In sched_mm_cid_migrate_to, use mm->nr_cpus_allowed rather than t->nr_cpus_allowed. This criterion was really meant to compare the number of mm->mm_users to the number of CPUs allowed for the entire mm. Therefore, the prior comparison worked fine when all threads shared the same CPUs allowed mask, but not so much in scenarios where those threads have different masks (e.g. each thread pinned to a single CPU). This improvement is made possible by the addition of the per-mm CPUs allowed mask. * Benchmarks Each thread increments 16kB worth of 8-bit integers in bursts, with a configurable delay between each thread's execution. Each thread run one after the other (no threads run concurrently). The order of thread execution in the sequence is random. The thread execution sequence begins again after all threads have executed. The 16kB areas are allocated with rseq_mempool and indexed by either cpu_id, mm_cid (not cache-local), or cache-local mm_cid. Each thread is pinned to its own core. Testing configurations: 8-core/1-L3: Use 8 cores within a single L3 24-core/24-L3: Use 24 cores, 1 core per L3 192-core/24-L3: Use 192 cores (all cores in the system) 384-thread/24-L3: Use 384 HW threads (all HW threads in the system) Intermittent workload delays between threads: 200ms, 10ms. Hardware: CPU(s): 384 On-line CPU(s) list: 0-383 Vendor ID: AuthenticAMD Model name: AMD EPYC 9654 96-Core Processor Thread(s) per core: 2 Core(s) per socket: 96 Socket(s): 2 Caches (sum of all): L1d: 6 MiB (192 instances) L1i: 6 MiB (192 instances) L2: 192 MiB (192 instances) L3: 768 MiB (24 instances) Each result is an average of 5 test runs. The cache-local speedup is calculated as: (cache-local mm_cid) / (mm_cid). Intermittent workload delay: 200ms per-cpu mm_cid cache-local mm_cid cache-local speedup (ns) (ns) (ns) 8-core/1-L3 1374 19289 1336 14.4x 24-core/24-L3 2423 26721 1594 16.7x 192-core/24-L3 2291 15826 2153 7.3x 384-thread/24-L3 1874 13234 1907 6.9x Intermittent workload delay: 10ms per-cpu mm_cid cache-local mm_cid cache-local speedup (ns) (ns) (ns) 8-core/1-L3 662 756 686 1.1x 24-core/24-L3 1378 3648 1035 3.5x 192-core/24-L3 1439 10833 1482 7.3x 384-thread/24-L3 1503 10570 1556 6.8x [ This deprecates the prior "sched: NUMA-aware per-memory-map concurrency IDs" patch series with a simpler and more general approach. ] [ This patch applies on top of v6.12-rc1. ] Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Marco Elver <elver@google.com> Link: https://lore.kernel.org/lkml/20240823185946.418340-1-mathieu.desnoyers@efficios.com/
2024-09-21Merge tag 'mm-stable-2024-09-20-02-31' of ↵Linus Torvalds1-75/+6
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Along with the usual shower of singleton patches, notable patch series in this pull request are: - "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds consistency to the APIs and behaviour of these two core allocation functions. This also simplifies/enables Rustification. - "Some cleanups for shmem" from Baolin Wang. No functional changes - mode code reuse, better function naming, logic simplifications. - "mm: some small page fault cleanups" from Josef Bacik. No functional changes - code cleanups only. - "Various memory tiering fixes" from Zi Yan. A small fix and a little cleanup. - "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and simplifications and .text shrinkage. - "Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt. This is a feature, it adds new feilds to /proc/vmstat such as $ grep kstack /proc/vmstat kstack_1k 3 kstack_2k 188 kstack_4k 11391 kstack_8k 243 kstack_16k 0 which tells us that 11391 processes used 4k of stack while none at all used 16k. Useful for some system tuning things, but partivularly useful for "the dynamic kernel stack project". - "kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory. - "mm: memcg: page counters optimizations" from Roman Gushchin. "3 independent small optimizations of page counters". - "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David Hildenbrand. Improves PTE/PMD splitlock detection, makes powerpc/8xx work correctly by design rather than by accident. - "mm: remove arch_make_page_accessible()" from David Hildenbrand. Some folio conversions which make arch_make_page_accessible() unneeded. - "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel. Cleans up and fixes our handling of the resetting of the cgroup/process peak-memory-use detector. - "Make core VMA operations internal and testable" from Lorenzo Stoakes. Rationalizaion and encapsulation of the VMA manipulation APIs. With a view to better enable testing of the VMA functions, even from a userspace-only harness. - "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix issues in the zswap global shrinker, resulting in improved performance. - "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill in some missing info in /proc/zoneinfo. - "mm: replace follow_page() by folio_walk" from David Hildenbrand. Code cleanups and rationalizations (conversion to folio_walk()) resulting in the removal of follow_page(). - "improving dynamic zswap shrinker protection scheme" from Nhat Pham. Some tuning to improve zswap's dynamic shrinker. Significant reductions in swapin and improvements in performance are shown. - "mm: Fix several issues with unaccepted memory" from Kirill Shutemov. Improvements to the new unaccepted memory feature, - "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on DAX PUDs. This was missing, although nobody seems to have notied yet. - "Introduce a store type enum for the Maple tree" from Sidhartha Kumar. Cleanups and modest performance improvements for the maple tree library code. - "memcg: further decouple v1 code from v2" from Shakeel Butt. Move more cgroup v1 remnants away from the v2 memcg code. - "memcg: initiate deprecation of v1 features" from Shakeel Butt. Adds various warnings telling users that memcg v1 features are deprecated. - "mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li. Greatly improves the success rate of the mTHP swap allocation. - "mm: introduce numa_memblks" from Mike Rapoport. Moves various disparate per-arch implementations of numa_memblk code into generic code. - "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly improves the performance of munmap() of swap-filled ptes. - "support large folio swap-out and swap-in for shmem" from Baolin Wang. With this series we no longer split shmem large folios into simgle-page folios when swapping out shmem. - "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice performance improvements and code reductions for gigantic folios. - "support shmem mTHP collapse" from Baolin Wang. Adds support for khugepaged's collapsing of shmem mTHP folios. - "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect() performance regression due to the addition of mseal(). - "Increase the number of bits available in page_type" from Matthew Wilcox. Increases the number of bits available in page_type! - "Simplify the page flags a little" from Matthew Wilcox. Many legacy page flags are now folio flags, so the page-based flags and their accessors/mutators can be removed. - "mm: store zero pages to be swapped out in a bitmap" from Usama Arif. An optimization which permits us to avoid writing/reading zero-filled zswap pages to backing store. - "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race window which occurs when a MAP_FIXED operqtion is occurring during an unrelated vma tree walk. - "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of the vma_merge() functionality, making ot cleaner, more testable and better tested. - "misc fixups for DAMON {self,kunit} tests" from SeongJae Park. Minor fixups of DAMON selftests and kunit tests. - "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang. Code cleanups and folio conversions. - "Shmem mTHP controls and stats improvements" from Ryan Roberts. Cleanups for shmem controls and stats. - "mm: count the number of anonymous THPs per size" from Barry Song. Expose additional anon THP stats to userspace for improved tuning. - "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio conversions and removal of now-unused page-based APIs. - "replace per-quota region priorities histogram buffer with per-context one" from SeongJae Park. DAMON histogram rationalization. - "Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae Park. DAMON documentation updates. - "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve related doc and warn" from Jason Wang: fixes usage of page allocator __GFP_NOFAIL and GFP_ATOMIC flags. - "mm: split underused THPs" from Yu Zhao. Improve THP=always policy. This was overprovisioning THPs in sparsely accessed memory areas. - "zram: introduce custom comp backends API" frm Sergey Senozhatsky. Add support for zram run-time compression algorithm tuning. - "mm: Care about shadow stack guard gap when getting an unmapped area" from Mark Brown. Fix up the various arch_get_unmapped_area() implementations to better respect guard areas. - "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability of mem_cgroup_iter() and various code cleanups. - "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge pfnmap support. - "resource: Fix region_intersects() vs add_memory_driver_managed()" from Huang Ying. Fix a bug in region_intersects() for systems with CXL memory. - "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches a couple more code paths to correctly recover from the encountering of poisoned memry. - "mm: enable large folios swap-in support" from Barry Song. Support the swapin of mTHP memory into appropriately-sized folios, rather than into single-page folios" * tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits) zram: free secondary algorithms names uprobes: turn xol_area->pages[2] into xol_area->page uprobes: introduce the global struct vm_special_mapping xol_mapping Revert "uprobes: use vm_special_mapping close() functionality" mm: support large folios swap-in for sync io devices mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios mm: fix swap_read_folio_zeromap() for large folios with partial zeromap mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries set_memory: add __must_check to generic stubs mm/vma: return the exact errno in vms_gather_munmap_vmas() memcg: cleanup with !CONFIG_MEMCG_V1 mm/show_mem.c: report alloc tags in human readable units mm: support poison recovery from copy_present_page() mm: support poison recovery from do_cow_fault() resource, kunit: add test case for region_intersects() resource: make alloc_free_mem_region() works for iomem_resource mm: z3fold: deprecate CONFIG_Z3FOLD vfio/pci: implement huge_fault support mm/arm64: support large pfn mappings mm/x86: support large pfn mappings ...
2024-09-19Merge tag 'parisc-for-6.12-rc1' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc architecture updates from Helge Deller: - On parisc we now use the generic clockevent framework for timekeeping - Although there is no 64-bit glibc/userspace for parisc yet, for testing purposes one can run statically linked 64-bit binaries. This patchset contains two patches which fix 64-bit userspace which has been broken since kernel 4.19 - Fix the userspace stack position and size when the ADDR_NO_RANDOMIZE personality is enabled - On other architectures mmap(MAP_GROWSDOWN | MAP_STACK) creates a downward-growing stack. On parisc mmap(MAP_STACK) is now sufficient to create an upward-growing stack * tag 'parisc-for-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Allow mmap(MAP_STACK) memory to automatically expand upwards parisc: Use PRIV_USER instead of hardcoded value parisc: Fix itlb miss handler for 64-bit programs parisc: Fix 64-bit userspace syscall path parisc: Fix stack start for ADDR_NO_RANDOMIZE personality parisc: Convert to generic clockevents parisc: pdc_stable: Constify struct kobj_type
2024-09-09parisc: Fix stack start for ADDR_NO_RANDOMIZE personalityHelge Deller1-1/+2
Fix the stack start address calculation for the parisc architecture in setup_arg_pages() when address randomization is disabled. When the ADDR_NO_RANDOMIZE process personality is disabled there is no need to add additional space for the stack. Note that this patch touches code inside an #ifdef CONFIG_STACK_GROWSUP hunk, which is why only the parisc architecture is affected since it's the only Linux architecture where the stack grows upwards. Without this patch you will find the stack in the middle of some mapped libaries and suddenly limited to 6MB instead of 8MB: root@parisc:~# setarch -R /bin/bash -c "cat /proc/self/maps" 00010000-00019000 r-xp 00000000 08:05 1182034 /usr/bin/cat 00019000-0001a000 rwxp 00009000 08:05 1182034 /usr/bin/cat 0001a000-0003b000 rwxp 00000000 00:00 0 [heap] f90c4000-f9283000 r-xp 00000000 08:05 1573004 /usr/lib/hppa-linux-gnu/libc.so.6 f9283000-f9285000 r--p 001bf000 08:05 1573004 /usr/lib/hppa-linux-gnu/libc.so.6 f9285000-f928a000 rwxp 001c1000 08:05 1573004 /usr/lib/hppa-linux-gnu/libc.so.6 f928a000-f9294000 rwxp 00000000 00:00 0 f9301000-f9323000 rwxp 00000000 00:00 0 [stack] f98b4000-f98e4000 r-xp 00000000 08:05 1572869 /usr/lib/hppa-linux-gnu/ld.so.1 f98e4000-f98e5000 r--p 00030000 08:05 1572869 /usr/lib/hppa-linux-gnu/ld.so.1 f98e5000-f98e9000 rwxp 00031000 08:05 1572869 /usr/lib/hppa-linux-gnu/ld.so.1 f9ad8000-f9b00000 rw-p 00000000 00:00 0 f9b00000-f9b01000 r-xp 00000000 00:00 0 [vdso] With the patch the stack gets correctly mapped at the end of the process memory map: root@panama:~# setarch -R /bin/bash -c "cat /proc/self/maps" 00010000-00019000 r-xp 00000000 08:13 16385582 /usr/bin/cat 00019000-0001a000 rwxp 00009000 08:13 16385582 /usr/bin/cat 0001a000-0003b000 rwxp 00000000 00:00 0 [heap] fef29000-ff0eb000 r-xp 00000000 08:13 16122400 /usr/lib/hppa-linux-gnu/libc.so.6 ff0eb000-ff0ed000 r--p 001c2000 08:13 16122400 /usr/lib/hppa-linux-gnu/libc.so.6 ff0ed000-ff0f2000 rwxp 001c4000 08:13 16122400 /usr/lib/hppa-linux-gnu/libc.so.6 ff0f2000-ff0fc000 rwxp 00000000 00:00 0 ff4b4000-ff4e4000 r-xp 00000000 08:13 16121913 /usr/lib/hppa-linux-gnu/ld.so.1 ff4e4000-ff4e6000 r--p 00030000 08:13 16121913 /usr/lib/hppa-linux-gnu/ld.so.1 ff4e6000-ff4ea000 rwxp 00032000 08:13 16121913 /usr/lib/hppa-linux-gnu/ld.so.1 ff6d7000-ff6ff000 rw-p 00000000 00:00 0 ff6ff000-ff700000 r-xp 00000000 00:00 0 [vdso] ff700000-ff722000 rwxp 00000000 00:00 0 [stack] Reported-by: Camm Maguire <camm@maguirefamily.org> Signed-off-by: Helge Deller <deller@gmx.de> Fixes: d045c77c1a69 ("parisc,metag: Fix crashes due to stack randomization on stack-grows-upwards architectures") Fixes: 17d9822d4b4c ("parisc: Consider stack randomization for mmap base only when necessary") Cc: stable@vger.kernel.org # v5.2+
2024-09-01mm: move vma_shrink(), vma_expand() to internal headerLorenzo Stoakes1-75/+6
The vma_shrink() and vma_expand() functions are internal VMA manipulation functions which we ought to abstract for use outside of memory management code. To achieve this, we replace shift_arg_pages() in fs/exec.c with an invocation of a new relocate_vma_down() function implemented in mm/mmap.c, which enables us to also move move_page_tables() and vma_iter_prev_range() to internal.h. The purpose of doing this is to isolate key VMA manipulation functions in order that we can both abstract them and later render them easily testable. Link: https://lkml.kernel.org/r/3cfcd9ec433e032a85f636fdc0d7d98fafbd19c5.1722251717.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Gow <davidgow@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Kees Cook <kees@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Rae Moar <rmoar@google.com> Cc: SeongJae Park <sj@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Pengfei Xu <pengfei.xu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-08-30exec: don't WARN for racy path_noexec checkMateusz Guzik1-19/+12
Both i_mode and noexec checks wrapped in WARN_ON stem from an artifact of the previous implementation. They used to legitimately check for the condition, but that got moved up in two commits: 633fb6ac3980 ("exec: move S_ISREG() check earlier") 0fd338b2d2cd ("exec: move path_noexec() check earlier") Instead of being removed said checks are WARN_ON'ed instead, which has some debug value. However, the spurious path_noexec check is racy, resulting in unwarranted warnings should someone race with setting the noexec flag. One can note there is more to perm-checking whether execve is allowed and none of the conditions are guaranteed to still hold after they were tested for. Additionally this does not validate whether the code path did any perm checking to begin with -- it will pass if the inode happens to be regular. Keep the redundant path_noexec() check even though it's mindless nonsense checking for guarantee that isn't given so drop the WARN. Reword the commentary and do small tidy ups while here. Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20240805131721.765484-1-mjguzik@gmail.com [brauner: keep redundant path_noexec() check] Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-13exec: Fix ToCToU between perm check and set-uid/gid usageKees Cook1-1/+7
When opening a file for exec via do_filp_open(), permission checking is done against the file's metadata at that moment, and on success, a file pointer is passed back. Much later in the execve() code path, the file metadata (specifically mode, uid, and gid) is used to determine if/how to set the uid and gid. However, those values may have changed since the permissions check, meaning the execution may gain unintended privileges. For example, if a file could change permissions from executable and not set-id: ---------x 1 root root 16048 Aug 7 13:16 target to set-id and non-executable: ---S------ 1 root root 16048 Aug 7 13:16 target it is possible to gain root privileges when execution should have been disallowed. While this race condition is rare in real-world scenarios, it has been observed (and proven exploitable) when package managers are updating the setuid bits of installed programs. Such files start with being world-executable but then are adjusted to be group-exec with a set-uid bit. For example, "chmod o-x,u+s target" makes "target" executable only by uid "root" and gid "cdrom", while also becoming setuid-root: -rwxr-xr-x 1 root cdrom 16048 Aug 7 13:16 target becomes: -rwsr-xr-- 1 root cdrom 16048 Aug 7 13:16 target But racing the chmod means users without group "cdrom" membership can get the permission to execute "target" just before the chmod, and when the chmod finishes, the exec reaches brpm_fill_uid(), and performs the setuid to root, violating the expressed authorization of "only cdrom group members can setuid to root". Re-check that we still have execute permissions in case the metadata has changed. It would be better to keep a copy from the perm-check time, but until we can do that refactoring, the least-bad option is to do a full inode_permission() call (under inode lock). It is understood that this is safe against dead-locks, but hardly optimal. Reported-by: Marco Vanotti <mvanotti@google.com> Tested-by: Marco Vanotti <mvanotti@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@vger.kernel.org Cc: Eric Biederman <ebiederm@xmission.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Signed-off-by: Kees Cook <kees@kernel.org>
2024-07-24sysctl: treewide: constify the ctl_table argument of proc_handlersJoel Granados1-1/+1
const qualify the struct ctl_table argument in the proc_handler function signatures. This is a prerequisite to moving the static ctl_table structs into .rodata data which will ensure that proc_handler function pointers cannot be modified. This patch has been generated by the following coccinelle script: ``` virtual patch @r1@ identifier ctl, write, buffer, lenp, ppos; identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)"; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos); @r2@ identifier func, ctl, write, buffer, lenp, ppos; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos) { ... } @r3@ identifier func; @@ int func( - struct ctl_table * + const struct ctl_table * ,int , void *, size_t *, loff_t *); @r4@ identifier func, ctl; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int , void *, size_t *, loff_t *); @r5@ identifier func, write, buffer, lenp, ppos; @@ int func( - struct ctl_table * + const struct ctl_table * ,int write, void *buffer, size_t *lenp, loff_t *ppos); ``` * Code formatting was adjusted in xfs_sysctl.c to comply with code conventions. The xfs_stats_clear_proc_handler, xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where adjusted. * The ctl_table argument in proc_watchdog_common was const qualified. This is called from a proc_handler itself and is calling back into another proc_handler, making it necessary to change it as part of the proc_handler migration. Co-developed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Co-developed-by: Joel Granados <j.granados@samsung.com> Signed-off-by: Joel Granados <j.granados@samsung.com>
2024-07-23Merge tag 'execve-v6.11-rc1-fix1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull execve fix from Kees Cook: "This moves the exec and binfmt_elf tests out of your way and into the tests/ subdirectory, following the newly ratified KUnit naming conventions. :)" * tag 'execve-v6.11-rc1-fix1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: execve: Move KUnit tests to tests/ subdirectory
2024-07-22execve: Move KUnit tests to tests/ subdirectoryKees Cook1-1/+1
Move the exec KUnit tests into a separate directory to avoid polluting the local directory namespace. Additionally update MAINTAINERS for the new files. Reviewed-by: David Gow <davidgow@google.com> Reviewed-by: SeongJae Park <sj@kernel.org> Acked-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20240720170310.it.942-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2024-07-16Merge tag 'execve-v6.11-rc1' of ↵Linus Torvalds1-7/+42
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull execve updates from Kees Cook: - Use value of kernel.randomize_va_space once per exec (Alexey Dobriyan) - Honor PT_LOAD alignment for static PIE - Make bprm->argmin only visible under CONFIG_MMU - Add KUnit testing of bprm_stack_limits() * tag 'execve-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: exec: Avoid pathological argc, envc, and bprm->p values execve: Keep bprm->argmin behind CONFIG_MMU ELF: fix kernel.randomize_va_space double read exec: Add KUnit test for bprm_stack_limits() binfmt_elf: Honor PT_LOAD alignment for static PIE binfmt_elf: Calculate total_size earlier selftests/exec: Build both static and non-static load_address tests
2024-07-13exec: Avoid pathological argc, envc, and bprm->p valuesKees Cook1-1/+9
Make sure nothing goes wrong with the string counters or the bprm's belief about the stack pointer. Add checks and matching self-tests. Take special care for !CONFIG_MMU, since argmin is not exposed there. For 32-bit validation, 32-bit UML was used: $ tools/testing/kunit/kunit.py run \ --make_options CROSS_COMPILE=i686-linux-gnu- \ --make_options SUBARCH=i386 \ exec For !MMU validation, m68k was used: $ tools/testing/kunit/kunit.py run \ --arch m68k --make_option CROSS_COMPILE=m68k-linux-gnu- \ exec Link: https://lore.kernel.org/r/20240520021615.741800-2-keescook@chromium.org Link: https://lore.kernel.org/r/20240621205046.4001362-2-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2024-07-13execve: Keep bprm->argmin behind CONFIG_MMUKees Cook1-6/+20
When argmin was added in commit 655c16a8ce9c ("exec: separate MM_ANONPAGES and RLIMIT_STACK accounting"), it was intended only for validating stack limits on CONFIG_MMU[1]. All checking for reaching the limit (argmin) is wrapped in CONFIG_MMU ifdef checks, though setting argmin was not. That argmin is only supposed to be used under CONFIG_MMU was rediscovered recently[2], and I don't want to trip over this again. Move argmin's declaration into the existing CONFIG_MMU area, and add helpers functions so the MMU tests can be consolidated. Link: https://lore.kernel.org/all/20181126122307.GA1660@redhat.com [1] Link: https://lore.kernel.org/all/202406211253.7037F69@keescook/ [2] Link: https://lore.kernel.org/r/20240621205046.4001362-1-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2024-06-19exec: Add KUnit test for bprm_stack_limits()Kees Cook1-0/+13
Since bprm_stack_limits() operates with very limited side-effects, add it as the first exec.c KUnit test. Add to Kconfig and adjust MAINTAINERS file to include it. Tested on 64-bit UML: $ tools/testing/kunit/kunit.py run exec Link: https://lore.kernel.org/lkml/20240520021615.741800-1-keescook@chromium.org/ Signed-off-by: Kees Cook <kees@kernel.org>
2024-06-03fs: don't block i_writecount during execChristian Brauner1-11/+3
Back in 2021 we already discussed removing deny_write_access() for executables. Back then I was hesistant because I thought that this might cause issues in userspace. But even back then I had started taking some notes on what could potentially depend on this and I didn't come up with a lot so I've changed my mind and I would like to try this. Here are some of the notes that I took: (1) The deny_write_access() mechanism is causing really pointless issues such as [1]. If a thread in a thread-group opens a file writable, then writes some stuff, then closing the file descriptor and then calling execve() they can fail the execve() with ETXTBUSY because another thread in the thread-group could have concurrently called fork(). Multi-threaded libraries such as go suffer from this. (2) There are userspace attacks that rely on overwriting the binary of a running process. These attacks are _mitigated_ but _not at all prevented_ from ocurring by the deny_write_access() mechanism. I'll go over some details. The clearest example of such attacks was the attack against runC in CVE-2019-5736 (cf. [3]). An attack could compromise the runC host binary from inside a _privileged_ runC container. The malicious binary could then be used to take over the host. (It is crucial to note that this attack is _not_ possible with unprivileged containers. IOW, the setup here is already insecure.) The attack can be made when attaching to a running container or when starting a container running a specially crafted image. For example, when runC attaches to a container the attacker can trick it into executing itself. This could be done by replacing the target binary inside the container with a custom binary pointing back at the runC binary itself. As an example, if the target binary was /bin/bash, this could be replaced with an executable script specifying the interpreter path #!/proc/self/exe. As such when /bin/bash is executed inside the container, instead the target of /proc/self/exe will be executed. That magic link will point to the runc binary on the host. The attacker can then proceed to write to the target of /proc/self/exe to try and overwrite the runC binary on the host. However, this will not succeed because of deny_write_access(). Now, one might think that this would prevent the attack but it doesn't. To overcome this, the attacker has multiple ways: * Open a file descriptor to /proc/self/exe using the O_PATH flag and then proceed to reopen the binary as O_WRONLY through /proc/self/fd/<nr> and try to write to it in a busy loop from a separate process. Ultimately it will succeed when the runC binary exits. After this the runC binary is compromised and can be used to attack other containers or the host itself. * Use a malicious shared library annotating a function in there with the constructor attribute making the malicious function run as an initializor. The malicious library will then open /proc/self/exe for creating a new entry under /proc/self/fd/<nr>. It'll then call exec to a) force runC to exit and b) hand the file descriptor off to a program that then reopens /proc/self/fd/<nr> for writing (which is now possible because runC has exited) and overwriting that binary. To sum up: the deny_write_access() mechanism doesn't prevent such attacks in insecure setups. It just makes them minimally harder. That's all. The only way back then to prevent this is to create a temporary copy of the calling binary itself when it starts or attaches to containers. So what I did back then for LXC (and Aleksa for runC) was to create an anonymous, in-memory file using the memfd_create() system call and to copy itself into the temporary in-memory file, which is then sealed to prevent further modifications. This sealed, in-memory file copy is then executed instead of the original on-disk binary. Any compromising write operations from a privileged container to the host binary will then write to the temporary in-memory binary and not to the host binary on-disk, preserving the integrity of the host binary. Also as the temporary, in-memory binary is sealed, writes to this will also fail. The point is that deny_write_access() is uselss to prevent these attacks. (3) Denying write access to an inode because it's currently used in an exec path could easily be done on an LSM level. It might need an additional hook but that should be about it. (4) The MAP_DENYWRITE flag for mmap() has been deprecated a long time ago so while we do protect the main executable the bigger portion of the things you'd think need protecting such as the shared libraries aren't. IOW, we let anyone happily overwrite shared libraries. (5) We removed all remaining uses of VM_DENYWRITE in [2]. That means: (5.1) We removed the legacy uselib() protection for preventing overwriting of shared libraries. Nobody cared in 3 years. (5.2) We allow write access to the elf interpreter after exec completed treating it on a par with shared libraries. Yes, someone in userspace could potentially be relying on this. It's not completely out of the realm of possibility but let's find out if that's actually the case and not guess. Link: https://github.com/golang/go/issues/22315 [1] Link: 49624efa65ac ("Merge tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux") [2] Link: https://unit42.paloaltonetworks.com/breaking-docker-via-runc-explaining-cve-2019-5736 [3] Link: https://lwn.net/Articles/866493 Link: https://github.com/golang/go/issues/22220 Link: https://github.com/golang/go/blob/5bf8c0cf09ee5c7e5a37ab90afcce154ab716a97/src/cmd/go/internal/work/buildid.go#L724 Link: https://github.com/golang/go/blob/5bf8c0cf09ee5c7e5a37ab90afcce154ab716a97/src/cmd/go/internal/work/exec.go#L1493 Link: https://github.com/golang/go/blob/5bf8c0cf09ee5c7e5a37ab90afcce154ab716a97/src/cmd/go/internal/script/cmds.go#L457 Link: https://github.com/golang/go/blob/5bf8c0cf09ee5c7e5a37ab90afcce154ab716a97/src/cmd/go/internal/test/test.go#L1557 Link: https://github.com/golang/go/blob/5bf8c0cf09ee5c7e5a37ab90afcce154ab716a97/src/os/exec/lp_linux_test.go#L61 Link: https://github.com/buildkite/agent/pull/2736 Link: https://github.com/rust-lang/rust/issues/114554 Link: https://bugs.openjdk.org/browse/JDK-8068370 Link: https://github.com/dotnet/runtime/issues/58964 Link: https://lore.kernel.org/r/20240531-vfs-i_writecount-v1-1-a17bea7ee36b@kernel.org Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-05-19Merge tag 'mm-stable-2024-05-17-19-19' of ↵Linus Torvalds1-0/+11
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull mm updates from Andrew Morton: "The usual shower of singleton fixes and minor series all over MM, documented (hopefully adequately) in the respective changelogs. Notable series include: - Lucas Stach has provided some page-mapping cleanup/consolidation/ maintainability work in the series "mm/treewide: Remove pXd_huge() API". - In the series "Allow migrate on protnone reference with MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's MPOL_PREFERRED_MANY mode, yielding almost doubled performance in one test. - In their series "Memory allocation profiling" Kent Overstreet and Suren Baghdasaryan have contributed a means of determining (via /proc/allocinfo) whereabouts in the kernel memory is being allocated: number of calls and amount of memory. - Matthew Wilcox has provided the series "Various significant MM patches" which does a number of rather unrelated things, but in largely similar code sites. - In his series "mm: page_alloc: freelist migratetype hygiene" Johannes Weiner has fixed the page allocator's handling of migratetype requests, with resulting improvements in compaction efficiency. - In the series "make the hugetlb migration strategy consistent" Baolin Wang has fixed a hugetlb migration issue, which should improve hugetlb allocation reliability. - Liu Shixin has hit an I/O meltdown caused by readahead in a memory-tight memcg. Addressed in the series "Fix I/O high when memory almost met memcg limit". - In the series "mm/filemap: optimize folio adding and splitting" Kairui Song has optimized pagecache insertion, yielding ~10% performance improvement in one test. - Baoquan He has cleaned up and consolidated the early zone initialization code in the series "mm/mm_init.c: refactor free_area_init_core()". - Baoquan has also redone some MM initializatio code in the series "mm/init: minor clean up and improvement". - MM helper cleanups from Christoph Hellwig in his series "remove follow_pfn". - More cleanups from Matthew Wilcox in the series "Various page->flags cleanups". - Vlastimil Babka has contributed maintainability improvements in the series "memcg_kmem hooks refactoring". - More folio conversions and cleanups in Matthew Wilcox's series: "Convert huge_zero_page to huge_zero_folio" "khugepaged folio conversions" "Remove page_idle and page_young wrappers" "Use folio APIs in procfs" "Clean up __folio_put()" "Some cleanups for memory-failure" "Remove page_mapping()" "More folio compat code removal" - David Hildenbrand chipped in with "fs/proc/task_mmu: convert hugetlb functions to work on folis". - Code consolidation and cleanup work related to GUP's handling of hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2". - Rick Edgecombe has developed some fixes to stack guard gaps in the series "Cover a guard gap corner case". - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the series "mm/ksm: fix ksm exec support for prctl". - Baolin Wang has implemented NUMA balancing for multi-size THPs. This is a simple first-cut implementation for now. The series is "support multi-size THP numa balancing". - Cleanups to vma handling helper functions from Matthew Wilcox in the series "Unify vma_address and vma_pgoff_address". - Some selftests maintenance work from Dev Jain in the series "selftests/mm: mremap_test: Optimizations and style fixes". - Improvements to the swapping of multi-size THPs from Ryan Roberts in the series "Swap-out mTHP without splitting". - Kefeng Wang has significantly optimized the handling of arm64's permission page faults in the series "arch/mm/fault: accelerate pagefault when badaccess" "mm: remove arch's private VM_FAULT_BADMAP/BADACCESS" - GUP cleanups from David Hildenbrand in "mm/gup: consistently call it GUP-fast". - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault path to use struct vm_fault". - selftests build fixes from John Hubbard in the series "Fix selftests/mm build without requiring "make headers"". - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the series "Improved Memory Tier Creation for CPUless NUMA Nodes". Fixes the initialization code so that migration between different memory types works as intended. - David Hildenbrand has improved follow_pte() and fixed an errant driver in the series "mm: follow_pte() improvements and acrn follow_pte() fixes". - David also did some cleanup work on large folio mapcounts in his series "mm: mapcount for large folios + page_mapcount() cleanups". - Folio conversions in KSM in Alex Shi's series "transfer page to folio in KSM". - Barry Song has added some sysfs stats for monitoring multi-size THP's in the series "mm: add per-order mTHP alloc and swpout counters". - Some zswap cleanups from Yosry Ahmed in the series "zswap same-filled and limit checking cleanups". - Matthew Wilcox has been looking at buffer_head code and found the documentation to be lacking. The series is "Improve buffer head documentation". - Multi-size THPs get more work, this time from Lance Yang. His series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free" optimizes the freeing of these things. - Kemeng Shi has added more userspace-visible writeback instrumentation in the series "Improve visibility of writeback". - Kemeng Shi then sent some maintenance work on top in the series "Fix and cleanups to page-writeback". - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in the series "Improve anon_vma scalability for anon VMAs". Intel's test bot reported an improbable 3x improvement in one test. - SeongJae Park adds some DAMON feature work in the series "mm/damon: add a DAMOS filter type for page granularity access recheck" "selftests/damon: add DAMOS quota goal test" - Also some maintenance work in the series "mm/damon/paddr: simplify page level access re-check for pageout" "mm/damon: misc fixes and improvements" - David Hildenbrand has disabled some known-to-fail selftests ni the series "selftests: mm: cow: flag vmsplice() hugetlb tests as XFAIL". - memcg metadata storage optimizations from Shakeel Butt in "memcg: reduce memory consumption by memcg stats". - DAX fixes and maintenance work from Vishal Verma in the series "dax/bus.c: Fixups for dax-bus locking"" * tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits) memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault selftests: cgroup: add tests to verify the zswap writeback path mm: memcg: make alloc_mem_cgroup_per_node_info() return bool mm/damon/core: fix return value from damos_wmark_metric_value mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED selftests: cgroup: remove redundant enabling of memory controller Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT Docs/mm/damon/design: use a list for supported filters Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file selftests/damon: classify tes