October 2024 - Linux-stable-mirror

[merged mm-hotfixes-stable] x86-traps-move-kmsan-check-after-instrumentation_begin.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: x86/traps: move kmsan check after instrumentation_begin has been removed from the -mm tree. Its filename was x86-traps-move-kmsan-check-after-instrumentation_begin.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Sabyrzhan Tasbolatov <snovitoll(a)gmail.com> Subject: x86/traps: move kmsan check after instrumentation_begin Date: Wed, 16 Oct 2024 20:24:07 +0500 During x86_64 kernel build with CONFIG_KMSAN, the objtool warns following: AR built-in.a AR vmlinux.a LD vmlinux.o vmlinux.o: warning: objtool: handle_bug+0x4: call to kmsan_unpoison_entry_regs() leaves .noinstr.text section OBJCOPY modules.builtin.modinfo GEN modules.builtin MODPOST Module.symvers CC .vmlinux.export.o Moving kmsan_unpoison_entry_regs() _after_ instrumentation_begin() fixes the warning. There is decode_bug(regs->ip, &imm) is left before KMSAN unpoisoining, but it has the return condition and if we include it after instrumentation_begin() it results the warning "return with instrumentation enabled", hence, I'm concerned that regs will not be KMSAN unpoisoned if `ud_type == BUG_NONE` is true. Link: https://lkml.kernel.org/r/20241016152407.3149001-1-snovitoll@gmail.com Fixes: ba54d194f8da ("x86/traps: avoid KMSAN bugs originating from handle_bug()") Signed-off-by: Sabyrzhan Tasbolatov <snovitoll(a)gmail.com> Reviewed-by: Alexander Potapenko <glider(a)google.com> Cc: Borislav Petkov (AMD) <bp(a)alien8.de> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- arch/x86/kernel/traps.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/arch/x86/kernel/traps.c~x86-traps-move-kmsan-check-after-instrumentation_begin +++ a/arch/x86/kernel/traps.c @@ -261,12 +261,6 @@ static noinstr bool handle_bug(struct pt int ud_type; u32 imm; - /* - * Normally @regs are unpoisoned by irqentry_enter(), but handle_bug() - * is a rare case that uses @regs without passing them to - * irqentry_enter(). - */ - kmsan_unpoison_entry_regs(regs); ud_type = decode_bug(regs->ip, &imm); if (ud_type == BUG_NONE) return handled; @@ -276,6 +270,12 @@ static noinstr bool handle_bug(struct pt */ instrumentation_begin(); /* + * Normally @regs are unpoisoned by irqentry_enter(), but handle_bug() + * is a rare case that uses @regs without passing them to + * irqentry_enter(). + */ + kmsan_unpoison_entry_regs(regs); + /* * Since we're emulating a CALL with exceptions, restore the interrupt * state to what it was at the exception site. */ _ Patches currently in -mm which might be from snovitoll(a)gmail.com are mm-kasan-kmsan-copy_from-to_kernel_nofault.patch kasan-move-checks-to-do_strncpy_from_user.patch kasan-migrate-copy_user_test-to-kunit.patch kasan-delete-config_kasan_module_test.patch kasan-delete-config_kasan_module_test-fix.patch

2 months, 1 week

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[merged mm-hotfixes-stable] mm-page_alloc-let-gfp_atomic-order-0-allocs-access-highatomic-reserves.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: mm/page_alloc: let GFP_ATOMIC order-0 allocs access highatomic reserves has been removed from the -mm tree. Its filename was mm-page_alloc-let-gfp_atomic-order-0-allocs-access-highatomic-reserves.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Matt Fleming <mfleming(a)cloudflare.com> Subject: mm/page_alloc: let GFP_ATOMIC order-0 allocs access highatomic reserves Date: Fri, 11 Oct 2024 13:07:37 +0100 Under memory pressure it's possible for GFP_ATOMIC order-0 allocations to fail even though free pages are available in the highatomic reserves. GFP_ATOMIC allocations cannot trigger unreserve_highatomic_pageblock() since it's only run from reclaim. Given that such allocations will pass the watermarks in __zone_watermark_unusable_free(), it makes sense to fallback to highatomic reserves the same way that ALLOC_OOM can. This fixes order-0 page allocation failures observed on Cloudflare's fleet when handling network packets: kswapd1: page allocation failure: order:0, mode:0x820(GFP_ATOMIC), nodemask=(null),cpuset=/,mems_allowed=0-7 CPU: 10 PID: 696 Comm: kswapd1 Kdump: loaded Tainted: G O 6.6.43-CUSTOM #1 Hardware name: MACHINE Call Trace: <IRQ> dump_stack_lvl+0x3c/0x50 warn_alloc+0x13a/0x1c0 __alloc_pages_slowpath.constprop.0+0xc9d/0xd10 __alloc_pages+0x327/0x340 __napi_alloc_skb+0x16d/0x1f0 bnxt_rx_page_skb+0x96/0x1b0 [bnxt_en] bnxt_rx_pkt+0x201/0x15e0 [bnxt_en] __bnxt_poll_work+0x156/0x2b0 [bnxt_en] bnxt_poll+0xd9/0x1c0 [bnxt_en] __napi_poll+0x2b/0x1b0 bpf_trampoline_6442524138+0x7d/0x1000 __napi_poll+0x5/0x1b0 net_rx_action+0x342/0x740 handle_softirqs+0xcf/0x2b0 irq_exit_rcu+0x6c/0x90 sysvec_apic_timer_interrupt+0x72/0x90 </IRQ> [mfleming(a)cloudflare.com: update comment] Link: https://lkml.kernel.org/r/20241015125158.3597702-1-matt@readmodwrite.com Link: https://lkml.kernel.org/r/20241011120737.3300370-1-matt@readmodwrite.com Link: https://lore.kernel.org/all/CAGis_TWzSu=P7QJmjD58WWiu3zjMTVKSzdOwWE8ORaGytz… Fixes: 1d91df85f399 ("mm/page_alloc: handle a missing case for memalloc_nocma_{save/restore} APIs") Signed-off-by: Matt Fleming <mfleming(a)cloudflare.com> Suggested-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Cc: Mel Gorman <mgorman(a)techsingularity.net> Cc: Michal Hocko <mhocko(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/page_alloc.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/mm/page_alloc.c~mm-page_alloc-let-gfp_atomic-order-0-allocs-access-highatomic-reserves +++ a/mm/page_alloc.c @@ -2893,12 +2893,12 @@ struct page *rmqueue_buddy(struct zone * page = __rmqueue(zone, order, migratetype, alloc_flags); /* - * If the allocation fails, allow OOM handling access - * to HIGHATOMIC reserves as failing now is worse than - * failing a high-order atomic allocation in the - * future. + * If the allocation fails, allow OOM handling and + * order-0 (atomic) allocs access to HIGHATOMIC + * reserves as failing now is worse than failing a + * high-order atomic allocation in the future. */ - if (!page && (alloc_flags & ALLOC_OOM)) + if (!page && (alloc_flags & (ALLOC_OOM|ALLOC_NON_BLOCK))) page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); if (!page) { _ Patches currently in -mm which might be from mfleming(a)cloudflare.com are

2 months, 1 week

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[merged mm-hotfixes-stable] fork-only-invoke-khugepaged-ksm-hooks-if-no-error.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: fork: only invoke khugepaged, ksm hooks if no error has been removed from the -mm tree. Its filename was fork-only-invoke-khugepaged-ksm-hooks-if-no-error.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Subject: fork: only invoke khugepaged, ksm hooks if no error Date: Tue, 15 Oct 2024 18:56:06 +0100 There is no reason to invoke these hooks early against an mm that is in an incomplete state. The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent. Their placement early in dup_mmap() only appears to have been meaningful for early error checking, and since functionally it'd require a very small allocation to fail (in practice 'too small to fail') that'd only occur in the most dire circumstances, meaning the fork would fail or be OOM'd in any case. Since both khugepaged and KSM tracking are there to provide optimisations to memory performance rather than critical functionality, it doesn't really matter all that much if, under such dire memory pressure, we fail to register an mm with these. As a result, we follow the example of commit d2081b2bf819 ("mm: khugepaged: make khugepaged_enter() void function") and make ksm_fork() a void function also. We only expose the mm to these functions once we are done with them and only if no error occurred in the fork operation. Link: https://lkml.kernel.org/r/e0cb8b840c9d1d5a6e84d4f8eff5f3f2022aa10c.17290143… Fixes: d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Alexander Viro <viro(a)zeniv.linux.org.uk> Cc: Christian Brauner <brauner(a)kernel.org> Cc: Jan Kara <jack(a)suse.cz> Cc: Linus Torvalds <torvalds(a)linuxfoundation.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/ksm.h | 10 ++++------ kernel/fork.c | 7 ++----- 2 files changed, 6 insertions(+), 11 deletions(-) --- a/include/linux/ksm.h~fork-only-invoke-khugepaged-ksm-hooks-if-no-error +++ a/include/linux/ksm.h @@ -54,12 +54,11 @@ static inline long mm_ksm_zero_pages(str return atomic_long_read(&mm->ksm_zero_pages); } -static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) +static inline void ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { + /* Adding mm to ksm is best effort on fork. */ if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) - return __ksm_enter(mm); - - return 0; + __ksm_enter(mm); } static inline int ksm_execve(struct mm_struct *mm) @@ -107,9 +106,8 @@ static inline int ksm_disable(struct mm_ return 0; } -static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) +static inline void ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { - return 0; } static inline int ksm_execve(struct mm_struct *mm) --- a/kernel/fork.c~fork-only-invoke-khugepaged-ksm-hooks-if-no-error +++ a/kernel/fork.c @@ -653,11 +653,6 @@ static __latent_entropy int dup_mmap(str mm->exec_vm = oldmm->exec_vm; mm->stack_vm = oldmm->stack_vm; - retval = ksm_fork(mm, oldmm); - if (retval) - goto out; - khugepaged_fork(mm, oldmm); - /* Use __mt_dup() to efficiently build an identical maple tree. */ retval = __mt_dup(&oldmm->mm_mt, &mm->mm_mt, GFP_KERNEL); if (unlikely(retval)) @@ -760,6 +755,8 @@ loop_out: vma_iter_free(&vmi); if (!retval) { mt_set_in_rcu(vmi.mas.tree); + ksm_fork(mm, oldmm); + khugepaged_fork(mm, oldmm); } else if (mpnt) { /* * The entire maple tree has already been duplicated. If the _ Patches currently in -mm which might be from lorenzo.stoakes(a)oracle.com are mm-avoid-unsafe-vma-hook-invocation-when-error-arises-on-mmap-hook.patch mm-unconditionally-close-vmas-on-error.patch mm-refactor-map_deny_write_exec.patch mm-resolve-faulty-mmap_region-error-path-behaviour.patch selftests-mm-add-pkey_sighandler_xx-hugetlb_dio-to-gitignore.patch mm-refactor-mm_access-to-not-return-null.patch mm-refactor-mm_access-to-not-return-null-fix.patch mm-madvise-unrestrict-process_madvise-for-current-process.patch maple_tree-do-not-hash-pointers-on-dump-in-debug-mode.patch tools-testing-fix-phys_addr_t-size-on-64-bit-systems.patch tools-testing-fix-phys_addr_t-size-on-64-bit-systems-fix.patch tools-testing-add-additional-vma_internalh-stubs.patch mm-isolate-mmap-internal-logic-to-mm-vmac.patch mm-refactor-__mmap_region.patch mm-defer-second-attempt-at-merge-on-mmap.patch mm-pagewalk-add-the-ability-to-install-ptes.patch mm-add-pte_marker_guard-pte-marker.patch mm-madvise-implement-lightweight-guard-page-mechanism.patch tools-testing-update-tools-uapi-header-for-mman-commonh.patch selftests-mm-add-self-tests-for-guard-page-feature.patch

2 months, 1 week

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[merged mm-hotfixes-stable] fork-do-not-invoke-uffd-on-fork-if-error-occurs.patch removed from -mm tree

by Andrew Morton

The quilt patch titled Subject: fork: do not invoke uffd on fork if error occurs has been removed from the -mm tree. Its filename was fork-do-not-invoke-uffd-on-fork-if-error-occurs.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Subject: fork: do not invoke uffd on fork if error occurs Date: Tue, 15 Oct 2024 18:56:05 +0100 Patch series "fork: do not expose incomplete mm on fork". During fork we may place the virtual memory address space into an inconsistent state before the fork operation is complete. In addition, we may encounter an error during the fork operation that indicates that the virtual memory address space is invalidated. As a result, we should not be exposing it in any way to external machinery that might interact with the mm or VMAs, machinery that is not designed to deal with incomplete state. We specifically update the fork logic to defer khugepaged and ksm to the end of the operation and only to be invoked if no error arose, and disallow uffd from observing fork events should an error have occurred. This patch (of 2): Currently on fork we expose the virtual address space of a process to userland unconditionally if uffd is registered in VMAs, regardless of whether an error arose in the fork. This is performed in dup_userfaultfd_complete() which is invoked unconditionally, and performs two duties - invoking registered handlers for the UFFD_EVENT_FORK event via dup_fctx(), and clearing down userfaultfd_fork_ctx objects established in dup_userfaultfd(). This is problematic, because the virtual address space may not yet be correctly initialised if an error arose. The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent. We address this by, on fork error, ensuring that we roll back state that we would otherwise expect to clean up through the event being handled by userland and perform the memory freeing duty otherwise performed by dup_userfaultfd_complete(). We do this by implementing a new function, dup_userfaultfd_fail(), which performs the same loop, only decrementing reference counts. Note that we perform mmgrab() on the parent and child mm's, however userfaultfd_ctx_put() will mmdrop() this once the reference count drops to zero, so we will avoid memory leaks correctly here. Link: https://lkml.kernel.org/r/cover.1729014377.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/d3691d58bb58712b6fb3df2be441d175bd3cdf07.17290143… Fixes: d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Jann Horn <jannh(a)google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Cc: Alexander Viro <viro(a)zeniv.linux.org.uk> Cc: Christian Brauner <brauner(a)kernel.org> Cc: Jan Kara <jack(a)suse.cz> Cc: Linus Torvalds <torvalds(a)linuxfoundation.org> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/userfaultfd.c | 28 ++++++++++++++++++++++++++++ include/linux/userfaultfd_k.h | 5 +++++ kernel/fork.c | 5 ++++- 3 files changed, 37 insertions(+), 1 deletion(-) --- a/fs/userfaultfd.c~fork-do-not-invoke-uffd-on-fork-if-error-occurs +++ a/fs/userfaultfd.c @@ -692,6 +692,34 @@ void dup_userfaultfd_complete(struct lis } } +void dup_userfaultfd_fail(struct list_head *fcs) +{ + struct userfaultfd_fork_ctx *fctx, *n; + + /* + * An error has occurred on fork, we will tear memory down, but have + * allocated memory for fctx's and raised reference counts for both the + * original and child contexts (and on the mm for each as a result). + * + * These would ordinarily be taken care of by a user handling the event, + * but we are no longer doing so, so manually clean up here. + * + * mm tear down will take care of cleaning up VMA contexts. + */ + list_for_each_entry_safe(fctx, n, fcs, list) { + struct userfaultfd_ctx *octx = fctx->orig; + struct userfaultfd_ctx *ctx = fctx->new; + + atomic_dec(&octx->mmap_changing); + VM_BUG_ON(atomic_read(&octx->mmap_changing) < 0); + userfaultfd_ctx_put(octx); + userfaultfd_ctx_put(ctx); + + list_del(&fctx->list); + kfree(fctx); + } +} + void mremap_userfaultfd_prep(struct vm_area_struct *vma, struct vm_userfaultfd_ctx *vm_ctx) { --- a/include/linux/userfaultfd_k.h~fork-do-not-invoke-uffd-on-fork-if-error-occurs +++ a/include/linux/userfaultfd_k.h @@ -249,6 +249,7 @@ static inline bool vma_can_userfault(str extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *); extern void dup_userfaultfd_complete(struct list_head *); +void dup_userfaultfd_fail(struct list_head *); extern void mremap_userfaultfd_prep(struct vm_area_struct *, struct vm_userfaultfd_ctx *); @@ -351,6 +352,10 @@ static inline void dup_userfaultfd_compl { } +static inline void dup_userfaultfd_fail(struct list_head *l) +{ +} + static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma, struct vm_userfaultfd_ctx *ctx) { --- a/kernel/fork.c~fork-do-not-invoke-uffd-on-fork-if-error-occurs +++ a/kernel/fork.c @@ -775,7 +775,10 @@ out: mmap_write_unlock(mm); flush_tlb_mm(oldmm); mmap_write_unlock(oldmm); - dup_userfaultfd_complete(&uf); + if (!retval) + dup_userfaultfd_complete(&uf); + else + dup_userfaultfd_fail(&uf); fail_uprobe_end: uprobe_end_dup_mmap(); return retval; _ Patches currently in -mm which might be from lorenzo.stoakes(a)oracle.com are mm-avoid-unsafe-vma-hook-invocation-when-error-arises-on-mmap-hook.patch mm-unconditionally-close-vmas-on-error.patch mm-refactor-map_deny_write_exec.patch mm-resolve-faulty-mmap_region-error-path-behaviour.patch selftests-mm-add-pkey_sighandler_xx-hugetlb_dio-to-gitignore.patch mm-refactor-mm_access-to-not-return-null.patch mm-refactor-mm_access-to-not-return-null-fix.patch mm-madvise-unrestrict-process_madvise-for-current-process.patch maple_tree-do-not-hash-pointers-on-dump-in-debug-mode.patch tools-testing-fix-phys_addr_t-size-on-64-bit-systems.patch tools-testing-fix-phys_addr_t-size-on-64-bit-systems-fix.patch tools-testing-add-additional-vma_internalh-stubs.patch mm-isolate-mmap-internal-logic-to-mm-vmac.patch mm-refactor-__mmap_region.patch mm-defer-second-attempt-at-merge-on-mmap.patch mm-pagewalk-add-the-ability-to-install-ptes.patch mm-add-pte_marker_guard-pte-marker.patch mm-madvise-implement-lightweight-guard-page-mechanism.patch tools-testing-update-tools-uapi-header-for-mman-commonh.patch selftests-mm-add-self-tests-for-guard-page-feature.patch

2 months, 1 week

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[PATCH xe-i915-for-6.11 01/22] drm/i915: Skip programming FIA link enable bits for MTL+

by Lucas De Marchi

From: Gustavo Sousa <gustavo.sousa(a)intel.com> commit 9fc97277eb2d17492de636b68cf7d2f5c4f15c1b upstream. Starting with Xe_LPD+, although FIA is still used to readout Type-C pin assignment, part of Type-C support is moved to PICA and programming PORT_TX_DFLEXDPMLE1(*) registers is not applicable anymore like it was for previous display IPs (e.g. see BSpec 49190). v2: - Mention Bspec 49190 as a reference of instructions for previous IPs. (Shekhar Chauhan) - s/Xe_LPDP/Xe_LPD+/ in the commit message. (Matt Roper) - Update commit message to be more accurate to the changes in the IP. (Imre Deak) Bspec: 65750, 65448 Reviewed-by: Shekhar Chauhan <shekhar.chauhan(a)intel.com> Reviewed-by: Imre Deak <imre.deak(a)intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240625202652.315936-1-gusta… Signed-off-by: Gustavo Sousa <gustavo.sousa(a)intel.com> Signed-off-by: Lucas De Marchi <lucas.demarchi(a)intel.com> --- drivers/gpu/drm/i915/display/intel_tc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c index 9887967b2ca5c..6f2ee7dbc43b3 100644 --- a/drivers/gpu/drm/i915/display/intel_tc.c +++ b/drivers/gpu/drm/i915/display/intel_tc.c @@ -393,6 +393,9 @@ void intel_tc_port_set_fia_lane_count(struct intel_digital_port *dig_port, bool lane_reversal = dig_port->saved_port_bits & DDI_BUF_PORT_REVERSAL; u32 val; + if (DISPLAY_VER(i915) >= 14) + return; + drm_WARN_ON(&i915->drm, lane_reversal && tc->mode != TC_PORT_LEGACY); -- 2.47.0

2 months, 1 week

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+ lib-string_helpers-fix-potential-snprintf-output-truncation.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: lib: string_helpers: fix potential snprintf() output truncation has been added to the -mm mm-hotfixes-unstable branch. Its filename is lib-string_helpers-fix-potential-snprintf-output-truncation.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Bartosz Golaszewski <bartosz.golaszewski(a)linaro.org> Subject: lib: string_helpers: fix potential snprintf() output truncation Date: Mon, 21 Oct 2024 11:14:17 +0200 The output of ".%03u" with the unsigned int in range [0, 4294966295] may get truncated if the target buffer is not 12 bytes. Link: https://lkml.kernel.org/r/20241021091417.37796-1-brgl@bgdev.pl Fixes: 3c9f3681d0b4 ("[SCSI] lib: add generic helper to print sizes rounded to the correct SI range") Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski(a)linaro.org> Reviewed-by: Andy Shevchenko <andy(a)kernel.org> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Kees Cook <kees(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- lib/string_helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/string_helpers.c~lib-string_helpers-fix-potential-snprintf-output-truncation +++ a/lib/string_helpers.c @@ -57,7 +57,7 @@ int string_get_size(u64 size, u64 blk_si static const unsigned int rounding[] = { 500, 50, 5 }; int i = 0, j; u32 remainder = 0, sf_cap; - char tmp[8]; + char tmp[12]; const char *unit; tmp[0] = '\0'; _ Patches currently in -mm which might be from bartosz.golaszewski(a)linaro.org are lib-string_helpers-fix-potential-snprintf-output-truncation.patch

2 months, 1 week

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+ mm-multi-gen-lru-use-pteppmdp_clear_young_notify.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm: multi-gen LRU: use {ptep,pmdp}_clear_young_notify() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-multi-gen-lru-use-pteppmdp_clear_young_notify.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Yu Zhao <yuzhao(a)google.com> Subject: mm: multi-gen LRU: use {ptep,pmdp}_clear_young_notify() Date: Sat, 19 Oct 2024 01:29:39 +0000 When the MM_WALK capability is enabled, memory that is mostly accessed by a VM appears younger than it really is, therefore this memory will be less likely to be evicted. Therefore, the presence of a running VM can significantly increase swap-outs for non-VM memory, regressing the performance for the rest of the system. Fix this regression by always calling {ptep,pmdp}_clear_young_notify() whenever we clear the young bits on PMDs/PTEs. Link: https://lkml.kernel.org/r/20241019012940.3656292-3-jthoughton@google.com Fixes: bd74fdaea146 ("mm: multi-gen LRU: support page table walks") Signed-off-by: Yu Zhao <yuzhao(a)google.com> Signed-off-by: James Houghton <jthoughton(a)google.com> Reported-by: David Stevens <stevensd(a)google.com> Cc: Axel Rasmussen <axelrasmussen(a)google.com> Cc: David Matlack <dmatlack(a)google.com> Cc: David Rientjes <rientjes(a)google.com> Cc: Oliver Upton <oliver.upton(a)linux.dev> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Sean Christopherson <seanjc(a)google.com> Cc: Wei Xu <weixugc(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/mmzone.h | 5 +- mm/rmap.c | 9 +-- mm/vmscan.c | 91 +++++++++++++++++++++------------------ 3 files changed, 55 insertions(+), 50 deletions(-) --- a/include/linux/mmzone.h~mm-multi-gen-lru-use-pteppmdp_clear_young_notify +++ a/include/linux/mmzone.h @@ -555,7 +555,7 @@ struct lru_gen_memcg { void lru_gen_init_pgdat(struct pglist_data *pgdat); void lru_gen_init_lruvec(struct lruvec *lruvec); -void lru_gen_look_around(struct page_vma_mapped_walk *pvmw); +bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw); void lru_gen_init_memcg(struct mem_cgroup *memcg); void lru_gen_exit_memcg(struct mem_cgroup *memcg); @@ -574,8 +574,9 @@ static inline void lru_gen_init_lruvec(s { } -static inline void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) +static inline bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw) { + return false; } static inline void lru_gen_init_memcg(struct mem_cgroup *memcg) --- a/mm/rmap.c~mm-multi-gen-lru-use-pteppmdp_clear_young_notify +++ a/mm/rmap.c @@ -885,13 +885,10 @@ static bool folio_referenced_one(struct return false; } - if (pvmw.pte) { - if (lru_gen_enabled() && - pte_young(ptep_get(pvmw.pte))) { - lru_gen_look_around(&pvmw); + if (lru_gen_enabled() && pvmw.pte) { + if (lru_gen_look_around(&pvmw)) referenced++; - } - + } else if (pvmw.pte) { if (ptep_clear_flush_young_notify(vma, address, pvmw.pte)) referenced++; --- a/mm/vmscan.c~mm-multi-gen-lru-use-pteppmdp_clear_young_notify +++ a/mm/vmscan.c @@ -56,6 +56,7 @@ #include <linux/khugepaged.h> #include <linux/rculist_nulls.h> #include <linux/random.h> +#include <linux/mmu_notifier.h> #include <asm/tlbflush.h> #include <asm/div64.h> @@ -3294,7 +3295,8 @@ static bool get_next_vma(unsigned long m return false; } -static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr) +static unsigned long get_pte_pfn(pte_t pte, struct vm_area_struct *vma, unsigned long addr, + struct pglist_data *pgdat) { unsigned long pfn = pte_pfn(pte); @@ -3306,13 +3308,20 @@ static unsigned long get_pte_pfn(pte_t p if (WARN_ON_ONCE(pte_devmap(pte) || pte_special(pte))) return -1; + if (!pte_young(pte) && !mm_has_notifiers(vma->vm_mm)) + return -1; + if (WARN_ON_ONCE(!pfn_valid(pfn))) return -1; + if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) + return -1; + return pfn; } -static unsigned long get_pmd_pfn(pmd_t pmd, struct vm_area_struct *vma, unsigned long addr) +static unsigned long get_pmd_pfn(pmd_t pmd, struct vm_area_struct *vma, unsigned long addr, + struct pglist_data *pgdat) { unsigned long pfn = pmd_pfn(pmd); @@ -3324,9 +3333,15 @@ static unsigned long get_pmd_pfn(pmd_t p if (WARN_ON_ONCE(pmd_devmap(pmd))) return -1; + if (!pmd_young(pmd) && !mm_has_notifiers(vma->vm_mm)) + return -1; + if (WARN_ON_ONCE(!pfn_valid(pfn))) return -1; + if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) + return -1; + return pfn; } @@ -3335,10 +3350,6 @@ static struct folio *get_pfn_folio(unsig { struct folio *folio; - /* try to avoid unnecessary memory loads */ - if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) - return NULL; - folio = pfn_folio(pfn); if (folio_nid(folio) != pgdat->node_id) return NULL; @@ -3394,20 +3405,16 @@ restart: total++; walk->mm_stats[MM_LEAF_TOTAL]++; - pfn = get_pte_pfn(ptent, args->vma, addr); + pfn = get_pte_pfn(ptent, args->vma, addr, pgdat); if (pfn == -1) continue; - if (!pte_young(ptent)) { - continue; - } - folio = get_pfn_folio(pfn, memcg, pgdat, walk->can_swap); if (!folio) continue; - if (!ptep_test_and_clear_young(args->vma, addr, pte + i)) - VM_WARN_ON_ONCE(true); + if (!ptep_clear_young_notify(args->vma, addr, pte + i)) + continue; young++; walk->mm_stats[MM_LEAF_YOUNG]++; @@ -3473,21 +3480,22 @@ static void walk_pmd_range_locked(pud_t /* don't round down the first address */ addr = i ? (*first & PMD_MASK) + i * PMD_SIZE : *first; - pfn = get_pmd_pfn(pmd[i], vma, addr); - if (pfn == -1) - goto next; - - if (!pmd_trans_huge(pmd[i])) { - if (!walk->force_scan && should_clear_pmd_young()) + if (pmd_present(pmd[i]) && !pmd_trans_huge(pmd[i])) { + if (!walk->force_scan && should_clear_pmd_young() && + !mm_has_notifiers(args->mm)) pmdp_test_and_clear_young(vma, addr, pmd + i); goto next; } + pfn = get_pmd_pfn(pmd[i], vma, addr, pgdat); + if (pfn == -1) + goto next; + folio = get_pfn_folio(pfn, memcg, pgdat, walk->can_swap); if (!folio) goto next; - if (!pmdp_test_and_clear_young(vma, addr, pmd + i)) + if (!pmdp_clear_young_notify(vma, addr, pmd + i)) goto next; walk->mm_stats[MM_LEAF_YOUNG]++; @@ -3545,24 +3553,18 @@ restart: } if (pmd_trans_huge(val)) { - unsigned long pfn = pmd_pfn(val); struct pglist_data *pgdat = lruvec_pgdat(walk->lruvec); + unsigned long pfn = get_pmd_pfn(val, vma, addr, pgdat); walk->mm_stats[MM_LEAF_TOTAL]++; - if (!pmd_young(val)) { - continue; - } - - /* try to avoid unnecessary memory loads */ - if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat)) - continue; - - walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first); + if (pfn != -1) + walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first); continue; } - if (!walk->force_scan && should_clear_pmd_young()) { + if (!walk->force_scan && should_clear_pmd_young() && + !mm_has_notifiers(args->mm)) { if (!pmd_young(val)) continue; @@ -4036,13 +4038,13 @@ static void lru_gen_age_node(struct pgli * the PTE table to the Bloom filter. This forms a feedback loop between the * eviction and the aging. */ -void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) +bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw) { int i; unsigned long start; unsigned long end; struct lru_gen_mm_walk *walk; - int young = 0; + int young = 1; pte_t *pte = pvmw->pte; unsigned long addr = pvmw->address; struct vm_area_struct *vma = pvmw->vma; @@ -4058,12 +4060,15 @@ void lru_gen_look_around(struct page_vma lockdep_assert_held(pvmw->ptl); VM_WARN_ON_ONCE_FOLIO(folio_test_lru(folio), folio); + if (!ptep_clear_young_notify(vma, addr, pte)) + return false; + if (spin_is_contended(pvmw->ptl)) - return; + return true; /* exclude special VMAs containing anon pages from COW */ if (vma->vm_flags & VM_SPECIAL) - return; + return true; /* avoid taking the LRU lock under the PTL when possible */ walk = current->reclaim_state ? current->reclaim_state->mm_walk : NULL; @@ -4071,6 +4076,9 @@ void lru_gen_look_around(struct page_vma start = max(addr & PMD_MASK, vma->vm_start); end = min(addr | ~PMD_MASK, vma->vm_end - 1) + 1; + if (end - start == PAGE_SIZE) + return true; + if (end - start > MIN_LRU_BATCH * PAGE_SIZE) { if (addr - start < MIN_LRU_BATCH * PAGE_SIZE / 2) end = start + MIN_LRU_BATCH * PAGE_SIZE; @@ -4084,7 +4092,7 @@ void lru_gen_look_around(struct page_vma /* folio_update_gen() requires stable folio_memcg() */ if (!mem_cgroup_trylock_pages(memcg)) - return; + return true; arch_enter_lazy_mmu_mode(); @@ -4094,19 +4102,16 @@ void lru_gen_look_around(struct page_vma unsigned long pfn; pte_t ptent = ptep_get(pte + i); - pfn = get_pte_pfn(ptent, vma, addr); + pfn = get_pte_pfn(ptent, vma, addr, pgdat); if (pfn == -1) continue; - if (!pte_young(ptent)) - continue; - folio = get_pfn_folio(pfn, memcg, pgdat, can_swap); if (!folio) continue; - if (!ptep_test_and_clear_young(vma, addr, pte + i)) - VM_WARN_ON_ONCE(true); + if (!ptep_clear_young_notify(vma, addr, pte + i)) + continue; young++; @@ -4136,6 +4141,8 @@ void lru_gen_look_around(struct page_vma /* feedback from rmap walkers to page table walkers */ if (mm_state && suitable_to_scan(i, young)) update_bloom_filter(mm_state, max_seq, pvmw->pmd); + + return true; } /****************************************************************************** _ Patches currently in -mm which might be from yuzhao(a)google.com are mm-allow-set-clear-page_type-again.patch mm-multi-gen-lru-remove-mm_leaf_old-and-mm_nonleaf_total-stats.patch mm-multi-gen-lru-use-pteppmdp_clear_young_notify.patch

2 months, 1 week

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+ mm-multi-gen-lru-remove-mm_leaf_old-and-mm_nonleaf_total-stats.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm: multi-gen LRU: remove MM_LEAF_OLD and MM_NONLEAF_TOTAL stats has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-multi-gen-lru-remove-mm_leaf_old-and-mm_nonleaf_total-stats.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Yu Zhao <yuzhao(a)google.com> Subject: mm: multi-gen LRU: remove MM_LEAF_OLD and MM_NONLEAF_TOTAL stats Date: Sat, 19 Oct 2024 01:29:38 +0000 Patch series "mm: multi-gen LRU: Have secondary MMUs participate in MM_WALK". Today, the MM_WALK capability causes MGLRU to clear the young bit from PMDs and PTEs during the page table walk before eviction, but MGLRU does not call the clear_young() MMU notifier in this case. By not calling this notifier, the MM walk takes less time/CPU, but it causes pages that are accessed mostly through KVM / secondary MMUs to appear younger than they should be. We do call the clear_young() notifier today, but only when attempting to evict the page, so we end up clearing young/accessed information less frequently for secondary MMUs than for mm PTEs, and therefore they appear younger and are less likely to be evicted. Therefore, memory that is *not* being accessed mostly by KVM will be evicted *more* frequently, worsening performance. ChromeOS observed a tab-open latency regression when enabling MGLRU with a setup that involved running a VM: Tab-open latency histogram (ms) Version p50 mean p95 p99 max base 1315 1198 2347 3454 10319 mglru 2559 1311 7399 12060 43758 fix 1119 926 2470 4211 6947 This series replaces the final non-selftest patchs from this series[1], which introduced a similar change (and a new MMU notifier) with KVM optimizations. I'll send a separate series (to Sean and Paolo) for the KVM optimizations. This series also makes proactive reclaim with MGLRU possible for KVM memory. I have verified that this functions correctly with the selftest from [1], but given that that test is a KVM selftest, I'll send it with the rest of the KVM optimizations later. Andrew, let me know if you'd like to take the test now anyway. [1]: https://lore.kernel.org/linux-mm/20240926013506.860253-18-jthoughton@google… This patch (of 2): The removed stats, MM_LEAF_OLD and MM_NONLEAF_TOTAL, are not very helpful and become more complicated to properly compute when adding test/clear_young() notifiers in MGLRU's mm walk. Link: https://lkml.kernel.org/r/20241019012940.3656292-1-jthoughton@google.com Link: https://lkml.kernel.org/r/20241019012940.3656292-2-jthoughton@google.com Fixes: bd74fdaea146 ("mm: multi-gen LRU: support page table walks") Signed-off-by: Yu Zhao <yuzhao(a)google.com> Signed-off-by: James Houghton <jthoughton(a)google.com> Cc: Axel Rasmussen <axelrasmussen(a)google.com> Cc: David Matlack <dmatlack(a)google.com> Cc: David Rientjes <rientjes(a)google.com> Cc: David Stevens <stevensd(a)google.com> Cc: Oliver Upton <oliver.upton(a)linux.dev> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Sean Christopherson <seanjc(a)google.com> Cc: Wei Xu <weixugc(a)google.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/mmzone.h | 2 -- mm/vmscan.c | 14 +++++--------- 2 files changed, 5 insertions(+), 11 deletions(-) --- a/include/linux/mmzone.h~mm-multi-gen-lru-remove-mm_leaf_old-and-mm_nonleaf_total-stats +++ a/include/linux/mmzone.h @@ -458,9 +458,7 @@ struct lru_gen_folio { enum { MM_LEAF_TOTAL, /* total leaf entries */ - MM_LEAF_OLD, /* old leaf entries */ MM_LEAF_YOUNG, /* young leaf entries */ - MM_NONLEAF_TOTAL, /* total non-leaf entries */ MM_NONLEAF_FOUND, /* non-leaf entries found in Bloom filters */ MM_NONLEAF_ADDED, /* non-leaf entries added to Bloom filters */ NR_MM_STATS --- a/mm/vmscan.c~mm-multi-gen-lru-remove-mm_leaf_old-and-mm_nonleaf_total-stats +++ a/mm/vmscan.c @@ -3399,7 +3399,6 @@ restart: continue; if (!pte_young(ptent)) { - walk->mm_stats[MM_LEAF_OLD]++; continue; } @@ -3552,7 +3551,6 @@ restart: walk->mm_stats[MM_LEAF_TOTAL]++; if (!pmd_young(val)) { - walk->mm_stats[MM_LEAF_OLD]++; continue; } @@ -3564,8 +3562,6 @@ restart: continue; } - walk->mm_stats[MM_NONLEAF_TOTAL]++; - if (!walk->force_scan && should_clear_pmd_young()) { if (!pmd_young(val)) continue; @@ -5254,11 +5250,11 @@ static void lru_gen_seq_show_full(struct for (tier = 0; tier < MAX_NR_TIERS; tier++) { seq_printf(m, " %10d", tier); for (type = 0; type < ANON_AND_FILE; type++) { - const char *s = " "; + const char *s = "xxx"; unsigned long n[3] = {}; if (seq == max_seq) { - s = "RT "; + s = "RTx"; n[0] = READ_ONCE(lrugen->avg_refaulted[type][tier]); n[1] = READ_ONCE(lrugen->avg_total[type][tier]); } else if (seq == min_seq[type] || NR_HIST_GENS > 1) { @@ -5280,14 +5276,14 @@ static void lru_gen_seq_show_full(struct seq_puts(m, " "); for (i = 0; i < NR_MM_STATS; i++) { - const char *s = " "; + const char *s = "xxxx"; unsigned long n = 0; if (seq == max_seq && NR_HIST_GENS == 1) { - s = "LOYNFA"; + s = "TYFA"; n = READ_ONCE(mm_state->stats[hist][i]); } else if (seq != max_seq && NR_HIST_GENS > 1) { - s = "loynfa"; + s = "tyfa"; n = READ_ONCE(mm_state->stats[hist][i]); } _ Patches currently in -mm which might be from yuzhao(a)google.com are mm-allow-set-clear-page_type-again.patch mm-multi-gen-lru-remove-mm_leaf_old-and-mm_nonleaf_total-stats.patch mm-multi-gen-lru-use-pteppmdp_clear_young_notify.patch

2 months, 1 week

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+ mm-allow-set-clear-page_type-again.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm: allow set/clear page_type again has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-allow-set-clear-page_type-again.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Yu Zhao <yuzhao(a)google.com> Subject: mm: allow set/clear page_type again Date: Sat, 19 Oct 2024 22:22:12 -0600 Some page flags (page->flags) were converted to page types (page->page_types). A recent example is PG_hugetlb. From the exclusive writer's perspective, e.g., a thread doing __folio_set_hugetlb(), there is a difference between the page flag and type APIs: the former allows the same non-atomic operation to be repeated whereas the latter does not. For example, calling __folio_set_hugetlb() twice triggers VM_BUG_ON_FOLIO(), since the second call expects the type (PG_hugetlb) not to be set previously. Using add_hugetlb_folio() as an example, it calls __folio_set_hugetlb() in the following error-handling path. And when that happens, it triggers the aforementioned VM_BUG_ON_FOLIO(). if (folio_test_hugetlb(folio)) { rc = hugetlb_vmemmap_restore_folio(h, folio); if (rc) { spin_lock_irq(&hugetlb_lock); add_hugetlb_folio(h, folio, false); ... It is possible to make hugeTLB comply with the new requirements from the page type API. However, a straightforward fix would be to just allow the same page type to be set or cleared again inside the API, to avoid any changes to its callers. Link: https://lkml.kernel.org/r/20241020042212.296781-1-yuzhao@google.com Fixes: d99e3140a4d3 ("mm: turn folio_test_hugetlb into a PageType") Signed-off-by: Yu Zhao <yuzhao(a)google.com> Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org> Cc: Muchun Song <muchun.song(a)linux.dev> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/page-flags.h | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/include/linux/page-flags.h~mm-allow-set-clear-page_type-again +++ a/include/linux/page-flags.h @@ -975,12 +975,16 @@ static __always_inline bool folio_test_# } \ static __always_inline void __folio_set_##fname(struct folio *folio) \ { \ + if (folio_test_##fname(folio)) \ + return; \ VM_BUG_ON_FOLIO(data_race(folio->page.page_type) != UINT_MAX, \ folio); \ folio->page.page_type = (unsigned int)PGTY_##lname << 24; \ } \ static __always_inline void __folio_clear_##fname(struct folio *folio) \ { \ + if (folio->page.page_type == UINT_MAX) \ + return; \ VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio); \ folio->page.page_type = UINT_MAX; \ } @@ -993,11 +997,15 @@ static __always_inline int Page##uname(c } \ static __always_inline void __SetPage##uname(struct page *page) \ { \ + if (Page##uname(page)) \ + return; \ VM_BUG_ON_PAGE(data_race(page->page_type) != UINT_MAX, page); \ page->page_type = (unsigned int)PGTY_##lname << 24; \ } \ static __always_inline void __ClearPage##uname(struct page *page) \ { \ + if (page->page_type == UINT_MAX) \ + return; \ VM_BUG_ON_PAGE(!Page##uname(page), page); \ page->page_type = UINT_MAX; \ } _ Patches currently in -mm which might be from yuzhao(a)google.com are mm-allow-set-clear-page_type-again.patch

2 months, 1 week

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+ nilfs2-fix-potential-deadlock-with-newly-created-symlinks.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: nilfs2: fix potential deadlock with newly created symlinks has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-fix-potential-deadlock-with-newly-created-symlinks.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Subject: nilfs2: fix potential deadlock with newly created symlinks Date: Sun, 20 Oct 2024 13:51:28 +0900 Syzbot reported that page_symlink(), called by nilfs_symlink(), triggers memory reclamation involving the filesystem layer, which can result in circular lock dependencies among the reader/writer semaphore nilfs->ns_segctor_sem, s_writers percpu_rwsem (intwrite) and the fs_reclaim pseudo lock. This is because after commit 21fc61c73c39 ("don't put symlink bodies in pagecache into highmem"), the gfp flags of the page cache for symbolic links are overwritten to GFP_KERNEL via inode_nohighmem(). This is not a problem for symlinks read from the backing device, because the __GFP_FS flag is dropped after inode_nohighmem() is called. However, when a new symlink is created with nilfs_symlink(), the gfp flags remain overwritten to GFP_KERNEL. Then, memory allocation called from page_symlink() etc. triggers memory reclamation including the FS layer, which may call nilfs_evict_inode() or nilfs_dirty_inode(). And these can cause a deadlock if they are called while nilfs->ns_segctor_sem is held: Fix this issue by dropping the __GFP_FS flag from the page cache GFP flags of newly created symlinks in the same way that nilfs_new_inode() and __nilfs_read_inode() do, as a workaround until we adopt nofs allocation scope consistently or improve the locking constraints. Link: https://lkml.kernel.org/r/20241020050003.4308-1-konishi.ryusuke@gmail.com Fixes: 21fc61c73c39 ("don't put symlink bodies in pagecache into highmem") Signed-off-by: Ryusuke Konishi <konishi.ryusuke(a)gmail.com> Reported-by: syzbot+9ef37ac20608f4836256(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9ef37ac20608f4836256 Tested-by: syzbot+9ef37ac20608f4836256(a)syzkaller.appspotmail.com Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- fs/nilfs2/namei.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/nilfs2/namei.c~nilfs2-fix-potential-deadlock-with-newly-created-symlinks +++ a/fs/nilfs2/namei.c @@ -157,6 +157,9 @@ static int nilfs_symlink(struct mnt_idma /* slow symlink */ inode->i_op = &nilfs_symlink_inode_operations; inode_nohighmem(inode); + mapping_set_gfp_mask(inode->i_mapping, + mapping_gfp_constraint(inode->i_mapping, + ~__GFP_FS)); inode->i_mapping->a_ops = &nilfs_aops; err = page_symlink(inode, symname, l); if (err) _ Patches currently in -mm which might be from konishi.ryusuke(a)gmail.com are nilfs2-fix-kernel-bug-due-to-missing-clearing-of-checked-flag.patch nilfs2-fix-potential-deadlock-with-newly-created-symlinks.patch

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Linux-stable-mirror October 2024