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[PATCH v1 4/4] mm/hugetlb: fix excessive IPI broadcasts when unsharing PMD tables using mmu_gather

by David Hildenbrand (Red Hat)

As reported, ever since commit 1013af4f585f ("mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race") we can end up in some situations where we perform so many IPI broadcasts when unsharing hugetlb PMD page tables that it severely regresses some workloads. In particular, when we fork()+exit(), or when we munmap() a large area backed by many shared PMD tables, we perform one IPI broadcast per unshared PMD table. There are two optimizations to be had: (1) When we process (unshare) multiple such PMD tables, such as during exit(), it is sufficient to send a single IPI broadcast (as long as we respect locking rules) instead of one per PMD table. Locking prevents that any of these PMD tables could get reuse before we drop the lock. (2) When we are not the last sharer (> 2 users including us), there is no need to send the IPI broadcast. The shared PMD tables cannot become exclusive (fully unshared) before an IPI will be broadcasted by the last sharer. Concurrent GUP-fast could walk into a PMD table just before we unshared it. It could then succeed in grabbing a page from the shared page table even after munmap() etc succeeded (and supressed an IPI). But there is not difference compared to GUP-fast just sleeping for a while after grabbing the page and re-enabling IRQs. Most importantly, GUP-fast will never walk into page tables that are no-longer shared, because the last sharer will issue an IPI broadcast. (if ever required, checking whether the PUD changed in GUP-fast after grabbing the page like we do in the PTE case could handle this) So let's rework PMD sharing TLB flushing + IPI sync to use the mmu_gather infrastructure so we can implement these optimizations and demystify the code at least a bit. Extend the mmu_gather infrastructure to be able to deal with our special hugetlb PMD table sharing implementation. We'll consolidate the handling for (full) unsharing of PMD tables in tlb_unshare_pmd_ptdesc() and tlb_flush_unshared_tables(), and track in "struct mmu_gather" whether we had (full) unsharing of PMD tables. Because locking is very special (concurrent unsharing+reuse must be prevented), we disallow deferring flushing to tlb_finish_mmu() and instead require an explicit earlier call to tlb_flush_unshared_tables(). From hugetlb code, we call huge_pmd_unshare_flush() where we make sure that the expected lock protecting us from concurrent unsharing+reuse is still held. Check with a VM_WARN_ON_ONCE() in tlb_finish_mmu() that tlb_flush_unshared_tables() was properly called earlier. Document it all properly. Notes about tlb_remove_table_sync_one() interaction with unsharing: There are two fairly tricky things: (1) tlb_remove_table_sync_one() is a NOP on architectures without CONFIG_MMU_GATHER_RCU_TABLE_FREE. Here, the assumption is that the previous TLB flush would send an IPI to all relevant CPUs. Careful: some architectures like x86 only send IPIs to all relevant CPUs when tlb->freed_tables is set. The relevant architectures should be selecting MMU_GATHER_RCU_TABLE_FREE, but x86 might not do that in stable kernels and it might have been problematic before this patch. Also, the arch flushing behavior (independent of IPIs) is different when tlb->freed_tables is set. Do we have to enlighten them to also take care of tlb->unshared_tables? So far we didn't care, so hopefully we are fine. Of course, we could be setting tlb->freed_tables as well, but that might then unnecessarily flush too much, because the semantics of tlb->freed_tables are a bit fuzzy. This patch changes nothing in this regard. (2) tlb_remove_table_sync_one() is not a NOP on architectures with CONFIG_MMU_GATHER_RCU_TABLE_FREE that actually don't need a sync. Take x86 as an example: in the common case (!pv, !X86_FEATURE_INVLPGB) we still issue IPIs during TLB flushes and don't actually need the second tlb_remove_table_sync_one(). This optimized can be implemented on top of this, by checking e.g., in tlb_remove_table_sync_one() whether we really need IPIs. But as described in (1), it really must honor tlb->freed_tables then to send IPIs to all relevant CPUs. Further note that the ptdesc_pmd_pts_dec() in huge_pmd_share() is not a concern, as we are holding the i_mmap_lock the whole time, preventing concurrent unsharing. That ptdesc_pmd_pts_dec() usage will be removed separately as a cleanup later. There are plenty more cleanups to be had, but they have to wait until this is fixed. Fixes: 1013af4f585f ("mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race") Reported-by: Uschakow, Stanislav" <suschako(a)amazon.de> Closes: https://lore.kernel.org/all/4d3878531c76479d9f8ca9789dc6485d@amazon.de/ Cc: <stable(a)vger.kernel.org> Signed-off-by: David Hildenbrand (Red Hat) <david(a)kernel.org> --- include/asm-generic/tlb.h | 69 +++++++++++++++++++++- include/linux/hugetlb.h | 19 +++--- mm/hugetlb.c | 121 ++++++++++++++++++++++---------------- mm/mmu_gather.c | 6 ++ mm/mprotect.c | 2 +- mm/rmap.c | 25 +++++--- 6 files changed, 173 insertions(+), 69 deletions(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 1fff717cae510..324a21f53b644 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -364,6 +364,17 @@ struct mmu_gather { unsigned int vma_huge : 1; unsigned int vma_pfn : 1; + /* + * Did we unshare (unmap) any shared page tables? + */ + unsigned int unshared_tables : 1; + + /* + * Did we unshare any page tables such that they are now exclusive + * and could get reused+modified by the new owner? + */ + unsigned int fully_unshared_tables : 1; + unsigned int batch_count; #ifndef CONFIG_MMU_GATHER_NO_GATHER @@ -400,6 +411,7 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb) tlb->cleared_pmds = 0; tlb->cleared_puds = 0; tlb->cleared_p4ds = 0; + tlb->unshared_tables = 0; /* * Do not reset mmu_gather::vma_* fields here, we do not * call into tlb_start_vma() again to set them if there is an @@ -484,7 +496,7 @@ static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) * these bits. */ if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds || - tlb->cleared_puds || tlb->cleared_p4ds)) + tlb->cleared_puds || tlb->cleared_p4ds || tlb->unshared_tables)) return; tlb_flush(tlb); @@ -773,6 +785,61 @@ static inline bool huge_pmd_needs_flush(pmd_t oldpmd, pmd_t newpmd) } #endif +#ifdef CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING +static inline void tlb_unshare_pmd_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt, + unsigned long addr) +{ + /* + * The caller must make sure that concurrent unsharing + exclusive + * reuse is impossible until tlb_flush_unshared_tables() was called. + */ + VM_WARN_ON_ONCE(!ptdesc_pmd_is_shared(pt)); + ptdesc_pmd_pts_dec(pt); + + /* Clearing a PUD pointing at a PMD table with PMD leaves. */ + tlb_flush_pmd_range(tlb, addr & PUD_MASK, PUD_SIZE); + + /* + * If the page table is now exclusively owned, we fully unshared + * a page table. + */ + if (!ptdesc_pmd_is_shared(pt)) + tlb->fully_unshared_tables = true; + tlb->unshared_tables = true; +} + +static inline void tlb_flush_unshared_tables(struct mmu_gather *tlb) +{ + /* + * As soon as the caller drops locks to allow for reuse of + * previously-shared tables, these tables could get modified and + * even reused outside of hugetlb context. So flush the TLB now. + * + * Note that we cannot defer the flush to a later point even if we are + * not the last sharer of the page table. + */ + if (tlb->unshared_tables) + tlb_flush_mmu_tlbonly(tlb); + + /* + * Similarly, we must make sure that concurrent GUP-fast will not + * walk previously-shared page tables that are getting modified+reused + * elsewhere. So broadcast an IPI to wait for any concurrent GUP-fast. + * + * We only perform this when we are the last sharer of a page table, + * as the IPI will reach all CPUs: any GUP-fast. + * + * Note that on configs where tlb_remove_table_sync_one() is a NOP, + * the expectation is that the tlb_flush_mmu_tlbonly() would have issued + * required IPIs already for us. + */ + if (tlb->fully_unshared_tables) { + tlb_remove_table_sync_one(); + tlb->fully_unshared_tables = false; + } +} +#endif /* CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ + #endif /* CONFIG_MMU */ #endif /* _ASM_GENERIC__TLB_H */ diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 03c8725efa289..63b248c6bfd47 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -240,8 +240,9 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz); unsigned long hugetlb_mask_last_page(struct hstate *h); -int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep); +int huge_pmd_unshare(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep); +void huge_pmd_unshare_flush(struct mmu_gather *tlb, struct vm_area_struct *vma); void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, unsigned long *start, unsigned long *end); @@ -271,7 +272,7 @@ void hugetlb_vma_unlock_write(struct vm_area_struct *vma); int hugetlb_vma_trylock_write(struct vm_area_struct *vma); void hugetlb_vma_assert_locked(struct vm_area_struct *vma); void hugetlb_vma_lock_release(struct kref *kref); -long hugetlb_change_protection(struct vm_area_struct *vma, +long hugetlb_change_protection(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot, unsigned long cp_flags); void hugetlb_unshare_all_pmds(struct vm_area_struct *vma); @@ -300,13 +301,17 @@ static inline struct address_space *hugetlb_folio_mapping_lock_write( return NULL; } -static inline int huge_pmd_unshare(struct mm_struct *mm, - struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +static inline int huge_pmd_unshare(struct mmu_gather *tlb, + struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { return 0; } +static inline void huge_pmd_unshare_flush(struct mmu_gather *tlb, + struct vm_area_struct *vma) +{ +} + static inline void adjust_range_if_pmd_sharing_possible( struct vm_area_struct *vma, unsigned long *start, unsigned long *end) @@ -432,7 +437,7 @@ static inline void move_hugetlb_state(struct folio *old_folio, { } -static inline long hugetlb_change_protection( +static inline long hugetlb_change_protection(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot, unsigned long cp_flags) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 3c77cdef12a32..3db94693a06fc 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5096,8 +5096,9 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, unsigned long last_addr_mask; pte_t *src_pte, *dst_pte; struct mmu_notifier_range range; - bool shared_pmd = false; + struct mmu_gather tlb; + tlb_gather_mmu(&tlb, vma->vm_mm); mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, old_addr, old_end); adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); @@ -5122,12 +5123,12 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, if (huge_pte_none(huge_ptep_get(mm, old_addr, src_pte))) continue; - if (huge_pmd_unshare(mm, vma, old_addr, src_pte)) { - shared_pmd = true; + if (huge_pmd_unshare(&tlb, vma, old_addr, src_pte)) { old_addr |= last_addr_mask; new_addr |= last_addr_mask; continue; } + tlb_remove_huge_tlb_entry(h, &tlb, src_pte, old_addr); dst_pte = huge_pte_alloc(mm, new_vma, new_addr, sz); if (!dst_pte) @@ -5136,13 +5137,13 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, move_huge_pte(vma, old_addr, new_addr, src_pte, dst_pte, sz); } - if (shared_pmd) - flush_hugetlb_tlb_range(vma, range.start, range.end); - else - flush_hugetlb_tlb_range(vma, old_end - len, old_end); + tlb_flush_mmu_tlbonly(&tlb); + huge_pmd_unshare_flush(&tlb, vma); + mmu_notifier_invalidate_range_end(&range); i_mmap_unlock_write(mapping); hugetlb_vma_unlock_write(vma); + tlb_finish_mmu(&tlb); return len + old_addr - old_end; } @@ -5161,7 +5162,6 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long sz = huge_page_size(h); bool adjust_reservation; unsigned long last_addr_mask; - bool force_flush = false; WARN_ON(!is_vm_hugetlb_page(vma)); BUG_ON(start & ~huge_page_mask(h)); @@ -5184,10 +5184,8 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, } ptl = huge_pte_lock(h, mm, ptep); - if (huge_pmd_unshare(mm, vma, address, ptep)) { + if (huge_pmd_unshare(tlb, vma, address, ptep)) { spin_unlock(ptl); - tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE); - force_flush = true; address |= last_addr_mask; continue; } @@ -5303,14 +5301,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, } tlb_end_vma(tlb, vma); - /* - * There is nothing protecting a previously-shared page table that we - * unshared through huge_pmd_unshare() from getting freed after we - * release i_mmap_rwsem, so flush the TLB now. If huge_pmd_unshare() - * succeeded, flush the range corresponding to the pud. - */ - if (force_flush) - tlb_flush_mmu_tlbonly(tlb); + huge_pmd_unshare_flush(tlb, vma); } void __hugetlb_zap_begin(struct vm_area_struct *vma, @@ -6399,7 +6390,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, } #endif /* CONFIG_USERFAULTFD */ -long hugetlb_change_protection(struct vm_area_struct *vma, +long hugetlb_change_protection(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot, unsigned long cp_flags) { @@ -6409,7 +6400,6 @@ long hugetlb_change_protection(struct vm_area_struct *vma, pte_t pte; struct hstate *h = hstate_vma(vma); long pages = 0, psize = huge_page_size(h); - bool shared_pmd = false; struct mmu_notifier_range range; unsigned long last_addr_mask; bool uffd_wp = cp_flags & MM_CP_UFFD_WP; @@ -6452,7 +6442,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, } } ptl = huge_pte_lock(h, mm, ptep); - if (huge_pmd_unshare(mm, vma, address, ptep)) { + if (huge_pmd_unshare(tlb, vma, address, ptep)) { /* * When uffd-wp is enabled on the vma, unshare * shouldn't happen at all. Warn about it if it @@ -6461,7 +6451,6 @@ long hugetlb_change_protection(struct vm_area_struct *vma, WARN_ON_ONCE(uffd_wp || uffd_wp_resolve); pages++; spin_unlock(ptl); - shared_pmd = true; address |= last_addr_mask; continue; } @@ -6522,22 +6511,16 @@ long hugetlb_change_protection(struct vm_area_struct *vma, pte = huge_pte_clear_uffd_wp(pte); huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte); pages++; + tlb_remove_huge_tlb_entry(h, tlb, ptep, address); } next: spin_unlock(ptl); cond_resched(); } - /* - * There is nothing protecting a previously-shared page table that we - * unshared through huge_pmd_unshare() from getting freed after we - * release i_mmap_rwsem, so flush the TLB now. If huge_pmd_unshare() - * succeeded, flush the range corresponding to the pud. - */ - if (shared_pmd) - flush_hugetlb_tlb_range(vma, range.start, range.end); - else - flush_hugetlb_tlb_range(vma, start, end); + + tlb_flush_mmu_tlbonly(tlb); + huge_pmd_unshare_flush(tlb, vma); /* * No need to call mmu_notifier_arch_invalidate_secondary_tlbs() we are * downgrading page table protection not changing it to point to a new @@ -6904,18 +6887,27 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, return pte; } -/* - * unmap huge page backed by shared pte. +/** + * huge_pmd_unshare - Unmap a pmd table if it is shared by multiple users + * @tlb: the current mmu_gather. + * @vma: the vma covering the pmd table. + * @addr: the address we are trying to unshare. + * @ptep: pointer into the (pmd) page table. + * + * Called with the page table lock held, the i_mmap_rwsem held in write mode + * and the hugetlb vma lock held in write mode. * - * Called with page table lock held. + * Note: The caller must call huge_pmd_unshare_flush() before dropping the + * i_mmap_rwsem. * - * returns: 1 successfully unmapped a shared pte page - * 0 the underlying pte page is not shared, or it is the last user + * Returns: 1 if it was a shared PMD table and it got unmapped, or 0 if it + * was not a shared PMD table. */ -int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +int huge_pmd_unshare(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) { unsigned long sz = huge_page_size(hstate_vma(vma)); + struct mm_struct *mm = vma->vm_mm; pgd_t *pgd = pgd_offset(mm, addr); p4d_t *p4d = p4d_offset(pgd, addr); pud_t *pud = pud_offset(p4d, addr); @@ -6927,18 +6919,36 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, i_mmap_assert_write_locked(vma->vm_file->f_mapping); hugetlb_vma_assert_locked(vma); pud_clear(pud); - /* - * Once our caller drops the rmap lock, some other process might be - * using this page table as a normal, non-hugetlb page table. - * Wait for pending gup_fast() in other threads to finish before letting - * that happen. - */ - tlb_remove_table_sync_one(); - ptdesc_pmd_pts_dec(virt_to_ptdesc(ptep)); + + tlb_unshare_pmd_ptdesc(tlb, virt_to_ptdesc(ptep), addr); + mm_dec_nr_pmds(mm); return 1; } +/* + * huge_pmd_unshare_flush - Complete a sequence of huge_pmd_unshare() calls + * @tlb: the current mmu_gather. + * @vma: the vma covering the pmd table. + * + * Perform necessary TLB flushes or IPI broadcasts to synchronize PMD table + * unsharing with concurrent page table walkers (TLB, GUP-fast, etc.). + * + * This function must be called after a sequence of huge_pmd_unshare() + * calls while still holding the i_mmap_rwsem. + */ +void huge_pmd_unshare_flush(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ + /* + * We must synchronize page table unsharing such that nobody will + * try reusing a previously-shared page table while it might still + * be in use by previous sharers (TLB, GUP_fast). + */ + i_mmap_assert_write_locked(vma->vm_file->f_mapping); + + tlb_flush_unshared_tables(tlb); +} + #else /* !CONFIG_HUGETLB_PMD_PAGE_TABLE_SHARING */ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, @@ -6947,12 +6957,16 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, return NULL; } -int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +int huge_pmd_unshare(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) { return 0; } +void huge_pmd_unshare_flush(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ +} + void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, unsigned long *start, unsigned long *end) { @@ -7219,6 +7233,7 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, unsigned long sz = huge_page_size(h); struct mm_struct *mm = vma->vm_mm; struct mmu_notifier_range range; + struct mmu_gather tlb; unsigned long address; spinlock_t *ptl; pte_t *ptep; @@ -7229,6 +7244,7 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, if (start >= end) return; + tlb_gather_mmu(&tlb, mm); flush_cache_range(vma, start, end); /* * No need to call adjust_range_if_pmd_sharing_possible(), because @@ -7248,10 +7264,10 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, if (!ptep) continue; ptl = huge_pte_lock(h, mm, ptep); - huge_pmd_unshare(mm, vma, address, ptep); + huge_pmd_unshare(&tlb, vma, address, ptep); spin_unlock(ptl); } - flush_hugetlb_tlb_range(vma, start, end); + huge_pmd_unshare_flush(&tlb, vma); if (take_locks) { i_mmap_unlock_write(vma->vm_file->f_mapping); hugetlb_vma_unlock_write(vma); @@ -7261,6 +7277,7 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, * Documentation/mm/mmu_notifier.rst. */ mmu_notifier_invalidate_range_end(&range); + tlb_finish_mmu(&tlb); } /* diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index 247e3f9db6c7a..822a790127375 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -468,6 +468,12 @@ void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm) */ void tlb_finish_mmu(struct mmu_gather *tlb) { + /* + * We expect an earlier huge_pmd_unshare_flush() call to sort this out, + * due to complicated locking requirements with page table unsharing. + */ + VM_WARN_ON_ONCE(tlb->fully_unshared_tables); + /* * If there are parallel threads are doing PTE changes on same range * under non-exclusive lock (e.g., mmap_lock read-side) but defer TLB diff --git a/mm/mprotect.c b/mm/mprotect.c index 283889e4f1cec..5c330e817129e 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -652,7 +652,7 @@ long change_protection(struct mmu_gather *tlb, #endif if (is_vm_hugetlb_page(vma)) - pages = hugetlb_change_protection(vma, start, end, newprot, + pages = hugetlb_change_protection(tlb, vma, start, end, newprot, cp_flags); else pages = change_protection_range(tlb, vma, start, end, newprot, diff --git a/mm/rmap.c b/mm/rmap.c index 748f48727a162..d6799afe11147 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -76,7 +76,7 @@ #include <linux/mm_inline.h> #include <linux/oom.h> -#include <asm/tlbflush.h> +#include <asm/tlb.h> #define CREATE_TRACE_POINTS #include <trace/events/migrate.h> @@ -2008,13 +2008,17 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, * if unsuccessful. */ if (!anon) { + struct mmu_gather tlb; + VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); if (!hugetlb_vma_trylock_write(vma)) goto walk_abort; - if (huge_pmd_unshare(mm, vma, address, pvmw.pte)) { + + tlb_gather_mmu(&tlb, mm); + if (huge_pmd_unshare(&tlb, vma, address, pvmw.pte)) { hugetlb_vma_unlock_write(vma); - flush_tlb_range(vma, - range.start, range.end); + huge_pmd_unshare_flush(&tlb, vma); + tlb_finish_mmu(&tlb); /* * The PMD table was unmapped, * consequently unmapping the folio. @@ -2022,6 +2026,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, goto walk_done; } hugetlb_vma_unlock_write(vma); + tlb_finish_mmu(&tlb); } pteval = huge_ptep_clear_flush(vma, address, pvmw.pte); if (pte_dirty(pteval)) @@ -2398,17 +2403,20 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, * fail if unsuccessful. */ if (!anon) { + struct mmu_gather tlb; + VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); if (!hugetlb_vma_trylock_write(vma)) { page_vma_mapped_walk_done(&pvmw); ret = false; break; } - if (huge_pmd_unshare(mm, vma, address, pvmw.pte)) { - hugetlb_vma_unlock_write(vma); - flush_tlb_range(vma, - range.start, range.end); + tlb_gather_mmu(&tlb, mm); + if (huge_pmd_unshare(&tlb, vma, address, pvmw.pte)) { + hugetlb_vma_unlock_write(vma); + huge_pmd_unshare_flush(&tlb, vma); + tlb_finish_mmu(&tlb); /* * The PMD table was unmapped, * consequently unmapping the folio. @@ -2417,6 +2425,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, break; } hugetlb_vma_unlock_write(vma); + tlb_finish_mmu(&tlb); } /* Nuke the hugetlb page table entry */ pteval = huge_ptep_clear_flush(vma, address, pvmw.pte); -- 2.52.0

1 day, 1 hour

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[PATCH v2] ocfs2: fix kernel BUG in ocfs2_write_block

by Prithvi Tambewagh

When the filesystem is being mounted, the kernel panics while the data regarding slot map allocation to the local node, is being written to the disk. This occurs because the value of slot map buffer head block number, which should have been greater than or equal to `OCFS2_SUPER_BLOCK_BLKNO` (evaluating to 2) is less than it, indicative of disk metadata corruption. This triggers BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO) in ocfs2_write_block(), causing the kernel to panic. This is fixed by introducing an if condition block in ocfs2_update_disk_slot(), right before calling ocfs2_write_block(), which checks if `bh->b_blocknr` is lesser than `OCFS2_SUPER_BLOCK_BLKNO`; if yes, then ocfs2_error is called, which prints the error log, for debugging purposes, and the return value of ocfs2_error() is returned back to caller of ocfs2_update_disk_slot() i.e. ocfs2_find_slot(). If the return value is zero. then error code EIO is returned. Reported-by: syzbot+c818e5c4559444f88aa0(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c818e5c4559444f88aa0 Tested-by: syzbot+c818e5c4559444f88aa0(a)syzkaller.appspotmail.com Cc: stable(a)vger.kernel.org Signed-off-by: Prithvi Tambewagh <activprithvi(a)gmail.com> --- v1->v2: - Remove usage of le16_to_cpu() from ocfs2_error() - Cast bh->b_blocknr to unsigned long long - Remove type casting for OCFS2_SUPER_BLOCK_BLKNO - Fix Sparse warnings reported in v1 by kernel test robot - Update title from 'ocfs2: Fix kernel BUG in ocfs2_write_block' to 'ocfs2: fix kernel BUG in ocfs2_write_block' v1 link: https://lore.kernel.org/all/20251206154819.175479-1-activprithvi@gmail.com/… fs/ocfs2/slot_map.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c index e544c704b583..e916a2e8f92d 100644 --- a/fs/ocfs2/slot_map.c +++ b/fs/ocfs2/slot_map.c @@ -193,6 +193,16 @@ static int ocfs2_update_disk_slot(struct ocfs2_super *osb, else ocfs2_update_disk_slot_old(si, slot_num, &bh); spin_unlock(&osb->osb_lock); + if (bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO) { + status = ocfs2_error(osb->sb, + "Invalid Slot Map Buffer Head " + "Block Number : %llu, Should be >= %d", + (unsigned long long)bh->b_blocknr, + OCFS2_SUPER_BLOCK_BLKNO); + if (!status) + return -EIO; + return status; + } status = ocfs2_write_block(osb, bh, INODE_CACHE(si->si_inode)); if (status < 0) base-commit: 24172e0d79900908cf5ebf366600616d29c9b417 -- 2.43.0

1 day, 1 hour

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[PATCH] USB: serial: ftdi_sio: add support for PICAXE AXE027 cable

by Ethan Nelson-Moore

The vendor provides instructions to write "0403 bd90" to /sys/bus/usb-serial/drivers/ftdi_sio/new_id; see: https://picaxe.com/docs/picaxe_linux_instructions.pdf Cc: stable(a)vger.kernel.org Signed-off-by: Ethan Nelson-Moore <enelsonmoore(a)gmail.com> --- drivers/usb/serial/ftdi_sio.c | 1 + drivers/usb/serial/ftdi_sio_ids.h | 2 ++ 2 files changed, 3 insertions(+) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index fe2f21d85737..acb48b1c83f7 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -848,6 +848,7 @@ static const struct usb_device_id id_table_combined[] = { { USB_DEVICE_INTERFACE_NUMBER(FTDI_VID, LMI_LM3S_DEVEL_BOARD_PID, 1) }, { USB_DEVICE_INTERFACE_NUMBER(FTDI_VID, LMI_LM3S_EVAL_BOARD_PID, 1) }, { USB_DEVICE_INTERFACE_NUMBER(FTDI_VID, LMI_LM3S_ICDI_BOARD_PID, 1) }, + { USB_DEVICE(FTDI_VID, FTDI_AXE027_PID) }, { USB_DEVICE_INTERFACE_NUMBER(FTDI_VID, FTDI_TURTELIZER_PID, 1) }, { USB_DEVICE(RATOC_VENDOR_ID, RATOC_PRODUCT_ID_USB60F) }, { USB_DEVICE(RATOC_VENDOR_ID, RATOC_PRODUCT_ID_SCU18) }, diff --git a/drivers/usb/serial/ftdi_sio_ids.h b/drivers/usb/serial/ftdi_sio_ids.h index 2539b9e2f712..6c76cfebfd0e 100644 --- a/drivers/usb/serial/ftdi_sio_ids.h +++ b/drivers/usb/serial/ftdi_sio_ids.h @@ -96,6 +96,8 @@ #define LMI_LM3S_EVAL_BOARD_PID 0xbcd9 #define LMI_LM3S_ICDI_BOARD_PID 0xbcda +#define FTDI_AXE027_PID 0xBD90 /* PICAXE AXE027 USB download cable */ + #define FTDI_TURTELIZER_PID 0xBDC8 /* JTAG/RS-232 adapter by egnite GmbH */ /* OpenDCC (www.opendcc.de) product id */ -- 2.43.0

1 day, 1 hour

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[PATCH] mpi3mr: Read missing IOCFacts flag for reply queue full overflow

by Chandrakanth Patil

The driver was not reading the MAX_REQ_PER_REPLY_QUEUE_LIMIT IOCFacts flag, so the reply-queue-full handling was never enabled even on firmware that supports it. Reading this flag enables the feature and prevents reply queue overflow Fixes: f08b24d82749 ("scsi: mpi3mr: Avoid reply queue full condition") Cc: stable(a)vger.kernel.org Signed-off-by: Chandrakanth Patil <chandrakanth.patil(a)broadcom.com> --- drivers/scsi/mpi3mr/mpi/mpi30_ioc.h | 1 + drivers/scsi/mpi3mr/mpi3mr_fw.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/drivers/scsi/mpi3mr/mpi/mpi30_ioc.h b/drivers/scsi/mpi3mr/mpi/mpi30_ioc.h index b42933fcd423..6561f98c3cb2 100644 --- a/drivers/scsi/mpi3mr/mpi/mpi30_ioc.h +++ b/drivers/scsi/mpi3mr/mpi/mpi30_ioc.h @@ -166,6 +166,7 @@ struct mpi3_ioc_facts_data { #define MPI3_IOCFACTS_FLAGS_SIGNED_NVDATA_REQUIRED (0x00010000) #define MPI3_IOCFACTS_FLAGS_DMA_ADDRESS_WIDTH_MASK (0x0000ff00) #define MPI3_IOCFACTS_FLAGS_DMA_ADDRESS_WIDTH_SHIFT (8) +#define MPI3_IOCFACTS_FLAGS_MAX_REQ_PER_REPLY_QUEUE_LIMIT (0x00000040) #define MPI3_IOCFACTS_FLAGS_INITIAL_PORT_ENABLE_MASK (0x00000030) #define MPI3_IOCFACTS_FLAGS_INITIAL_PORT_ENABLE_SHIFT (4) #define MPI3_IOCFACTS_FLAGS_INITIAL_PORT_ENABLE_NOT_STARTED (0x00000000) diff --git a/drivers/scsi/mpi3mr/mpi3mr_fw.c b/drivers/scsi/mpi3mr/mpi3mr_fw.c index 8fe6e0bf342e..8c4bb7169a87 100644 --- a/drivers/scsi/mpi3mr/mpi3mr_fw.c +++ b/drivers/scsi/mpi3mr/mpi3mr_fw.c @@ -3158,6 +3158,8 @@ static void mpi3mr_process_factsdata(struct mpi3mr_ioc *mrioc, mrioc->facts.dma_mask = (facts_flags & MPI3_IOCFACTS_FLAGS_DMA_ADDRESS_WIDTH_MASK) >> MPI3_IOCFACTS_FLAGS_DMA_ADDRESS_WIDTH_SHIFT; + mrioc->facts.max_req_limit = (facts_flags & + MPI3_IOCFACTS_FLAGS_MAX_REQ_PER_REPLY_QUEUE_LIMIT); mrioc->facts.protocol_flags = facts_data->protocol_flags; mrioc->facts.mpi_version = le32_to_cpu(facts_data->mpi_version.word); mrioc->facts.max_reqs = le16_to_cpu(facts_data->max_outstanding_requests); -- 2.47.1

1 day, 3 hours

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[PATCH] drm/nouveau/dispnv50: Don't call drm_atomic_get_crtc_state() in prepare_fb

by Lyude Paul

Since we recently started warning about uses of this function after the atomic check phase completes, we've started getting warnings about this in nouveau. It appears a misplaced drm_atomic_get_crtc_state() call has been hiding in our .prepare_fb callback for a while. So, fix this by adding a new nv50_head_atom_get_new() function and use that in our .prepare_fb callback instead. Signed-off-by: Lyude Paul <lyude(a)redhat.com> Fixes: 1590700d94ac ("drm/nouveau/kms/nv50-: split each resource type into their own source files") Cc: <stable(a)vger.kernel.org> # v4.18+ Signed-off-by: Lyude Paul <lyude(a)redhat.com> --- drivers/gpu/drm/nouveau/dispnv50/atom.h | 13 +++++++++++++ drivers/gpu/drm/nouveau/dispnv50/wndw.c | 2 +- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/nouveau/dispnv50/atom.h b/drivers/gpu/drm/nouveau/dispnv50/atom.h index 93f8f4f645784..85b7cf70d13c4 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/atom.h +++ b/drivers/gpu/drm/nouveau/dispnv50/atom.h @@ -152,8 +152,21 @@ static inline struct nv50_head_atom * nv50_head_atom_get(struct drm_atomic_state *state, struct drm_crtc *crtc) { struct drm_crtc_state *statec = drm_atomic_get_crtc_state(state, crtc); + if (IS_ERR(statec)) return (void *)statec; + + return nv50_head_atom(statec); +} + +static inline struct nv50_head_atom * +nv50_head_atom_get_new(struct drm_atomic_state *state, struct drm_crtc *crtc) +{ + struct drm_crtc_state *statec = drm_atomic_get_new_crtc_state(state, crtc); + + if (IS_ERR(statec)) + return (void*)statec; + return nv50_head_atom(statec); } diff --git a/drivers/gpu/drm/nouveau/dispnv50/wndw.c b/drivers/gpu/drm/nouveau/dispnv50/wndw.c index ef9e410babbfb..9a2c20fce0f3e 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/wndw.c +++ b/drivers/gpu/drm/nouveau/dispnv50/wndw.c @@ -583,7 +583,7 @@ nv50_wndw_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state) asyw->image.offset[0] = nvbo->offset; if (wndw->func->prepare) { - asyh = nv50_head_atom_get(asyw->state.state, asyw->state.crtc); + asyh = nv50_head_atom_get_new(asyw->state.state, asyw->state.crtc); if (IS_ERR(asyh)) return PTR_ERR(asyh); -- 2.52.0

1 day, 5 hours

3
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[PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end

by Ilpo Järvinen

__pci_read_base() sets resource start and end addresses when resource is larger than 4G but pci_bus_addr_t or resource_size_t are not capable of representing 64-bit PCI addresses. This creates a problematic resource that has non-zero flags but the start and end addresses do not yield to resource size of 0 but 1. Replace custom resource addresses setup with resource_set_range() that correctly sets end address as -1 which results in resource_size() returning 0. For consistency, also use resource_set_range() in the other branch that does size based resource setup. Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB") Link: https://lore.kernel.org/all/20251207215359.28895-1-ansuelsmth@gmail.com/T/#… Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Cc: stable(a)vger.kernel.org Cc: Christian Marangi <ansuelsmth(a)gmail.com> --- drivers/pci/probe.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 124d2d309c58..b8294a2f11f9 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -287,8 +287,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, if ((sizeof(pci_bus_addr_t) < 8 || sizeof(resource_size_t) < 8) && sz64 > 0x100000000ULL) { res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED; - res->start = 0; - res->end = 0; + resource_set_range(res, 0, 0); pci_err(dev, "%s: can't handle BAR larger than 4GB (size %#010llx)\n", res_name, (unsigned long long)sz64); goto out; @@ -297,8 +296,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, if ((sizeof(pci_bus_addr_t) < 8) && l) { /* Above 32-bit boundary; try to reallocate */ res->flags |= IORESOURCE_UNSET; - res->start = 0; - res->end = sz64 - 1; + resource_set_range(res, 0, sz64); pci_info(dev, "%s: can't handle BAR above 4GB (bus address %#010llx)\n", res_name, (unsigned long long)l64); goto out; base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0 -- 2.39.5

1 day, 6 hours

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FAILED: patch "[PATCH] net/mlx5e: Avoid field-overflowing memcpy()" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ad5185735f7dab342fdd0dd41044da4c9ccfef67 Mon Sep 17 00:00:00 2001 From: Kees Cook <keescook(a)chromium.org> Date: Mon, 24 Jan 2022 09:20:28 -0800 Subject: [PATCH] net/mlx5e: Avoid field-overflowing memcpy() In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Use flexible arrays instead of zero-element arrays (which look like they are always overflowing) and split the cross-field memcpy() into two halves that can be appropriately bounds-checked by the compiler. We were doing: #define ETH_HLEN 14 #define VLAN_HLEN 4 ... #define MLX5E_XDP_MIN_INLINE (ETH_HLEN + VLAN_HLEN) ... struct mlx5e_tx_wqe *wqe = mlx5_wq_cyc_get_wqe(wq, pi); ... struct mlx5_wqe_eth_seg *eseg = &wqe->eth; struct mlx5_wqe_data_seg *dseg = wqe->data; ... memcpy(eseg->inline_hdr.start, xdptxd->data, MLX5E_XDP_MIN_INLINE); target is wqe->eth.inline_hdr.start (which the compiler sees as being 2 bytes in size), but copying 18, intending to write across start (really vlan_tci, 2 bytes). The remaining 16 bytes get written into wqe->data[0], covering byte_count (4 bytes), lkey (4 bytes), and addr (8 bytes). struct mlx5e_tx_wqe { struct mlx5_wqe_ctrl_seg ctrl; /* 0 16 */ struct mlx5_wqe_eth_seg eth; /* 16 16 */ struct mlx5_wqe_data_seg data[]; /* 32 0 */ /* size: 32, cachelines: 1, members: 3 */ /* last cacheline: 32 bytes */ }; struct mlx5_wqe_eth_seg { u8 swp_outer_l4_offset; /* 0 1 */ u8 swp_outer_l3_offset; /* 1 1 */ u8 swp_inner_l4_offset; /* 2 1 */ u8 swp_inner_l3_offset; /* 3 1 */ u8 cs_flags; /* 4 1 */ u8 swp_flags; /* 5 1 */ __be16 mss; /* 6 2 */ __be32 flow_table_metadata; /* 8 4 */ union { struct { __be16 sz; /* 12 2 */ u8 start[2]; /* 14 2 */ } inline_hdr; /* 12 4 */ struct { __be16 type; /* 12 2 */ __be16 vlan_tci; /* 14 2 */ } insert; /* 12 4 */ __be32 trailer; /* 12 4 */ }; /* 12 4 */ /* size: 16, cachelines: 1, members: 9 */ /* last cacheline: 16 bytes */ }; struct mlx5_wqe_data_seg { __be32 byte_count; /* 0 4 */ __be32 lkey; /* 4 4 */ __be64 addr; /* 8 8 */ /* size: 16, cachelines: 1, members: 3 */ /* last cacheline: 16 bytes */ }; So, split the memcpy() so the compiler can reason about the buffer sizes. "pahole" shows no size nor member offset changes to struct mlx5e_tx_wqe nor struct mlx5e_umr_wqe. "objdump -d" shows no meaningful object code changes (i.e. only source line number induced differences and optimizations). Fixes: b5503b994ed5 ("net/mlx5e: XDP TX forwarding support") Signed-off-by: Kees Cook <keescook(a)chromium.org> Signed-off-by: Saeed Mahameed <saeedm(a)nvidia.com> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index 812e6810cb3b..c14e06ca64d8 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -224,7 +224,7 @@ static inline int mlx5e_get_max_num_channels(struct mlx5_core_dev *mdev) struct mlx5e_tx_wqe { struct mlx5_wqe_ctrl_seg ctrl; struct mlx5_wqe_eth_seg eth; - struct mlx5_wqe_data_seg data[0]; + struct mlx5_wqe_data_seg data[]; }; struct mlx5e_rx_wqe_ll { @@ -241,8 +241,8 @@ struct mlx5e_umr_wqe { struct mlx5_wqe_umr_ctrl_seg uctrl; struct mlx5_mkey_seg mkc; union { - struct mlx5_mtt inline_mtts[0]; - struct mlx5_klm inline_klms[0]; + DECLARE_FLEX_ARRAY(struct mlx5_mtt, inline_mtts); + DECLARE_FLEX_ARRAY(struct mlx5_klm, inline_klms); }; }; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c index 338d65e2c9ce..56e10c84a706 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c @@ -341,8 +341,10 @@ mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptxd, /* copy the inline part if required */ if (sq->min_inline_mode != MLX5_INLINE_MODE_NONE) { - memcpy(eseg->inline_hdr.start, xdptxd->data, MLX5E_XDP_MIN_INLINE); + memcpy(eseg->inline_hdr.start, xdptxd->data, sizeof(eseg->inline_hdr.start)); eseg->inline_hdr.sz = cpu_to_be16(MLX5E_XDP_MIN_INLINE); + memcpy(dseg, xdptxd->data + sizeof(eseg->inline_hdr.start), + MLX5E_XDP_MIN_INLINE - sizeof(eseg->inline_hdr.start)); dma_len -= MLX5E_XDP_MIN_INLINE; dma_addr += MLX5E_XDP_MIN_INLINE; dseg++;

1 day, 6 hours

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¿Cuánto cuesta una mala contratación?

by Valeria Pérez

¿Cuánto cuesta una mala contratación? body { margin: 0; padding: 0; font-family: Arial, Helvetica, sans-serif; font-size: 14px; color: #333; background-color: #ffffff; } table { border-spacing: 0; width: 100%; max-width: 600px; margin: auto; } td { padding: 12px 20px; } a { color: #1a73e8; text-decoration: none; } .footer { font-size: 12px; color: #888888; text-align: center; } Una mala contratación cuesta 3X el salario. Evítalo con datos, no percepciones. Hola, , ¿Sabías que una mala contratación cuesta hasta 3 veces el salario anual? El 74% de empresas admite haber contratado a la persona equivocada. El motivo: decisiones basadas en percepciones, no en datos objetivos. PsicoSmart te ayuda a evaluar talento con precisión: 31 pruebas psicométricas validadas para medir liderazgo, honestidad e inteligencia 2,500+ exámenes técnicos especializados por industria Verificación de identidad con captura fotográfica automática Resultados en minutos, accesible desde cualquier dispositivo Reduce hasta 60% el riesgo de error en selección. ¿Quieres una demostración gratuita? Responde este correo y te contacto en menos de 24 horas. Saludos, -------------- Atte.: Valeria Pérez Ciudad de México: (55) 5018 0565 WhatsApp: +52 33 1607 2089 Si no deseas recibir más correos, haz clic aquí para darte de baja. Para remover su dirección de esta lista haga <a href="https://s1.arrobamail.com/unsuscribe.php?id=yiwtsrewiswqtyseup">click aquí</a>

1 day, 8 hours

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[PATCH] mfd: core: Add locking around `mfd_of_node_list`

by Douglas Anderson

Manipulating a list in the kernel isn't safe without some sort of mutual exclusion. Add a mutex any time we access / modify `mfd_of_node_list` to prevent possible crashes. Cc: <stable(a)vger.kernel.org> Fixes: 466a62d7642f ("mfd: core: Make a best effort attempt to match devices with the correct of_nodes") Signed-off-by: Douglas Anderson <dianders(a)chromium.org> --- While I have no definitive way to reproduce the crash we've been seeing, it's clear that the `mfd_of_node_list` isn't right at the time of the crash. Code inspection shows the lack of locking. drivers/mfd/mfd-core.c | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index 7d14a1e7631e..c55223ce4327 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -22,6 +22,7 @@ #include <linux/regulator/consumer.h> static LIST_HEAD(mfd_of_node_list); +static DEFINE_MUTEX(mfd_of_node_mutex); struct mfd_of_node_entry { struct list_head list; @@ -105,9 +106,11 @@ static int mfd_match_of_node_to_dev(struct platform_device *pdev, u64 of_node_addr; /* Skip if OF node has previously been allocated to a device */ - list_for_each_entry(of_entry, &mfd_of_node_list, list) - if (of_entry->np == np) - return -EAGAIN; + scoped_guard(mutex, &mfd_of_node_mutex) { + list_for_each_entry(of_entry, &mfd_of_node_list, list) + if (of_entry->np == np) + return -EAGAIN; + } if (!cell->use_of_reg) /* No of_reg defined - allocate first free compatible match */ @@ -129,7 +132,8 @@ static int mfd_match_of_node_to_dev(struct platform_device *pdev, of_entry->dev = &pdev->dev; of_entry->np = np; - list_add_tail(&of_entry->list, &mfd_of_node_list); + scoped_guard(mutex, &mfd_of_node_mutex) + list_add_tail(&of_entry->list, &mfd_of_node_list); of_node_get(np); device_set_node(&pdev->dev, of_fwnode_handle(np)); @@ -286,11 +290,13 @@ static int mfd_add_device(struct device *parent, int id, if (cell->swnode) device_remove_software_node(&pdev->dev); fail_of_entry: - list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) - if (of_entry->dev == &pdev->dev) { - list_del(&of_entry->list); - kfree(of_entry); - } + scoped_guard(mutex, &mfd_of_node_mutex) { + list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) + if (of_entry->dev == &pdev->dev) { + list_del(&of_entry->list); + kfree(of_entry); + } + } fail_alias: regulator_bulk_unregister_supply_alias(&pdev->dev, cell->parent_supplies, @@ -360,11 +366,13 @@ static int mfd_remove_devices_fn(struct device *dev, void *data) if (cell->swnode) device_remove_software_node(&pdev->dev); - list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) - if (of_entry->dev == &pdev->dev) { - list_del(&of_entry->list); - kfree(of_entry); - } + scoped_guard(mutex, &mfd_of_node_mutex) { + list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) + if (of_entry->dev == &pdev->dev) { + list_del(&of_entry->list); + kfree(of_entry); + } + } regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies, cell->num_parent_supplies); -- 2.52.0.223.gf5cc29aaa4-goog

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NRF 2026 Retail's Big Show more information

by Connie Griggs

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