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6.1 Backport request: fbf5892df21a ("kbuild: Use CRC32 and a 1MiB dictionary for XZ compressed modules")

by Christoph Biedl

Hello, please backport commit fbf5892df21a8ccfcb2fda0fd65bc3169c89ed28 Author: Martin Nybo Andersen <tweek(a)tweek.dk> Date: Fri Sep 15 12:15:39 2023 +0200 kbuild: Use CRC32 and a 1MiB dictionary for XZ compressed modules Kmod is now (since kmod commit 09c9f8c5df04 ("libkmod: Use kernel decompression when available")) using the kernel decompressor, when loading compressed modules. However, the kernel XZ decompressor is XZ Embedded, which doesn't handle CRC64 and dictionaries larger than 1MiB. Use CRC32 and 1MiB dictionary when XZ compressing and installing kernel modules. to the 6.1 stable kernel, and possibly older ones as well. The commit message actually has it all, so just my story: There's a hardware that has or had issues with never kernels (no time to check), my kernel for this board is usually static. But after building a kernel with xz-compressed modules, they wouldn't load but trigger "decompression failed with status 6". Investigation led to a CRC64 check for these files, and eventually to the above commit. The commit applies (with an offset), the resulting modules work as expected. Kernel 6.6 and newer already have that commit. Older kernels could possibly benefit from this as well, I haven't checked. Kind regards, Christoph

3 days, 3 hours

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[PATCH] wifi: ath11k: fix qmi memory allocation logic for CALDB region

by Alexandru Gagniuc

Memory region assignment in ath11k_qmi_assign_target_mem_chunk() assumes that: 1. firmware will make a HOST_DDR_REGION_TYPE request, and 2. this request is processed before CALDB_MEM_REGION_TYPE In this case CALDB_MEM_REGION_TYPE, can safely be assigned immediately after the host region. However, if the HOST_DDR_REGION_TYPE request is not made, or the reserved-memory node is not present, then res.start and res.end are 0, and host_ddr_sz remains uninitialized. The physical address should fall back to ATH11K_QMI_CALDB_ADDRESS. That doesn't happen: resource_size(&res) returns 1 for an empty resource, and thus the if clause never takes the fallback path. ab->qmi.target_mem[idx].paddr is assigned the uninitialized value of host_ddr_sz + 0 (res.start). Use "if (res.end > res.start)" for the predicate, which correctly falls back to ATH11K_QMI_CALDB_ADDRESS. Fixes: 900730dc4705 ("wifi: ath: Use of_reserved_mem_region_to_resource() for "memory-region"") Cc: stable(a)vger.kernel.org # v6.18 Signed-off-by: Alexandru Gagniuc <mr.nuke.me(a)gmail.com> --- drivers/net/wireless/ath/ath11k/qmi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath/ath11k/qmi.c b/drivers/net/wireless/ath/ath11k/qmi.c index aea56c38bf8f3..6cc26d1c1e2a4 100644 --- a/drivers/net/wireless/ath/ath11k/qmi.c +++ b/drivers/net/wireless/ath/ath11k/qmi.c @@ -2054,7 +2054,7 @@ static int ath11k_qmi_assign_target_mem_chunk(struct ath11k_base *ab) return ret; } - if (res.end - res.start + 1 < ab->qmi.target_mem[i].size) { + if (resource_size(&res) < ab->qmi.target_mem[i].size) { ath11k_dbg(ab, ATH11K_DBG_QMI, "fail to assign memory of sz\n"); return -EINVAL; @@ -2086,7 +2086,7 @@ static int ath11k_qmi_assign_target_mem_chunk(struct ath11k_base *ab) } if (ath11k_core_coldboot_cal_support(ab)) { - if (resource_size(&res)) { + if (res.end > res.start) { ab->qmi.target_mem[idx].paddr = res.start + host_ddr_sz; ab->qmi.target_mem[idx].iaddr = -- 2.45.1

3 days, 3 hours

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[PATCH RESEND v3 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 reused 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. To make initialization of the mmu_gather easier when working on a single VMA (in particular, when dealing with hugetlb), provide tlb_gather_mmu_vma(). 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. Notes on TLB flushing changes: (1) Flushing for non-shared PMD tables We're converting from flush_hugetlb_tlb_range() to tlb_remove_huge_tlb_entry(). Given that we properly initialize the MMU gather in tlb_gather_mmu_vma() to be hugetlb aware, similar to __unmap_hugepage_range(), that should be fine. (2) Flushing for shared PMD tables We're converting from various things (flush_hugetlb_tlb_range(), tlb_flush_pmd_range(), flush_tlb_range()) to tlb_flush_pmd_range(). tlb_flush_pmd_range() achieves the same that tlb_remove_huge_tlb_entry() would achieve in these scenarios. Note that tlb_remove_huge_tlb_entry() also calls __tlb_remove_tlb_entry(), however that is only implemented on powerpc, which does not support PMD table sharing. Similar to (1), tlb_gather_mmu_vma() should make sure that TLB flushing keeps on working as expected. 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/ Tested-by: Laurence Oberman <loberman(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: David Hildenbrand (Red Hat) <david(a)kernel.org> --- include/asm-generic/tlb.h | 77 +++++++++++++++++++++++- include/linux/hugetlb.h | 15 +++-- include/linux/mm_types.h | 1 + mm/hugetlb.c | 123 ++++++++++++++++++++++---------------- mm/mmu_gather.c | 33 ++++++++++ mm/rmap.c | 25 +++++--- 6 files changed, 208 insertions(+), 66 deletions(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 1fff717cae510..4d679d2a206b4 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -46,7 +46,8 @@ * * The mmu_gather API consists of: * - * - tlb_gather_mmu() / tlb_gather_mmu_fullmm() / tlb_finish_mmu() + * - tlb_gather_mmu() / tlb_gather_mmu_fullmm() / tlb_gather_mmu_vma() / + * tlb_finish_mmu() * * start and finish a mmu_gather * @@ -364,6 +365,20 @@ struct mmu_gather { unsigned int vma_huge : 1; unsigned int vma_pfn : 1; + /* + * Did we unshare (unmap) any shared page tables? For now only + * used for hugetlb PMD table sharing. + */ + 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? When setting this + * flag, "unshared_tables" will be set as well. For now only used + * for hugetlb PMD table sharing. + */ + unsigned int fully_unshared_tables : 1; + unsigned int batch_count; #ifndef CONFIG_MMU_GATHER_NO_GATHER @@ -400,6 +415,7 @@ 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 +500,7 @@ 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 +789,63 @@ 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 we have to make sure that + * any page table walkers (incl. TLB, GUP-fast) are aware of that + * change. + * + * Even if we are not fully unsharing a PMD table, we must + * flush the TLB for the unsharer now. + */ + 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..e51b8ef0cebd9 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); @@ -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) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 42af2292951d4..d1053b2c1f800 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1522,6 +1522,7 @@ static inline unsigned int mm_cid_size(void) struct mmu_gather; extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm); extern void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm); +void tlb_gather_mmu_vma(struct mmu_gather *tlb, struct vm_area_struct *vma); extern void tlb_finish_mmu(struct mmu_gather *tlb); struct vm_fault; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 3c77cdef12a32..2609b6d58f99e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5096,7 +5096,7 @@ 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; mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, old_addr, old_end); @@ -5106,6 +5106,7 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, * range. */ flush_cache_range(vma, range.start, range.end); + tlb_gather_mmu_vma(&tlb, vma); mmu_notifier_invalidate_range_start(&range); last_addr_mask = hugetlb_mask_last_page(h); @@ -5122,8 +5123,7 @@ 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; @@ -5134,15 +5134,16 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, break; move_huge_pte(vma, old_addr, new_addr, src_pte, dst_pte, sz); + tlb_remove_huge_tlb_entry(h, &tlb, src_pte, old_addr); } - 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, @@ -6409,11 +6400,11 @@ 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; bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; + struct mmu_gather tlb; /* * In the case of shared PMDs, the area to flush could be beyond @@ -6426,6 +6417,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, BUG_ON(address >= end); flush_cache_range(vma, range.start, range.end); + tlb_gather_mmu_vma(&tlb, vma); mmu_notifier_invalidate_range_start(&range); hugetlb_vma_lock_write(vma); @@ -6452,7 +6444,7 @@ 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 +6453,6 @@ 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 +6513,16 @@ 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 @@ -6548,6 +6533,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, i_mmap_unlock_write(vma->vm_file->f_mapping); hugetlb_vma_unlock_write(vma); mmu_notifier_invalidate_range_end(&range); + tlb_finish_mmu(&tlb); return pages > 0 ? (pages << h->order) : pages; } @@ -6904,18 +6890,27 @@ 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 +6922,36 @@ 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. + * + * 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 +6960,16 @@ 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 +7236,7 @@ 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; @@ -7230,6 +7248,8 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, return; flush_cache_range(vma, start, end); + tlb_gather_mmu_vma(&tlb, vma); + /* * No need to call adjust_range_if_pmd_sharing_possible(), because * we have already done the PUD_SIZE alignment. @@ -7248,10 +7268,10 @@ 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 +7281,7 @@ 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..cd32c2dbf501b 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -10,6 +10,7 @@ #include <linux/swap.h> #include <linux/rmap.h> #include <linux/pgalloc.h> +#include <linux/hugetlb.h> #include <asm/tlb.h> @@ -426,6 +427,7 @@ static void __tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, #endif tlb->vma_pfn = 0; + tlb->fully_unshared_tables = 0; __tlb_reset_range(tlb); inc_tlb_flush_pending(tlb->mm); } @@ -459,6 +461,31 @@ void tlb_gather_mmu_fullmm(struct mmu_gather *tlb, struct mm_struct *mm) __tlb_gather_mmu(tlb, mm, true); } +/** + * tlb_gather_mmu - initialize an mmu_gather structure for operating on a single + * VMA + * @tlb: the mmu_gather structure to initialize + * @vma: the vm_area_struct + * + * Called to initialize an (on-stack) mmu_gather structure for operating on + * a single VMA. In contrast to tlb_gather_mmu(), calling this function will + * not require another call to tlb_start_vma(). In contrast to tlb_start_vma(), + * this function will *not* call flush_cache_range(). + * + * For hugetlb VMAs, this function will also initialize the mmu_gather + * page_size accordingly, not requiring a separate call to + * tlb_change_page_size(). + * + */ +void tlb_gather_mmu_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) +{ + tlb_gather_mmu(tlb, vma->vm_mm); + tlb_update_vma_flags(tlb, vma); + if (is_vm_hugetlb_page(vma)) + /* All entries have the same size. */ + tlb_change_page_size(tlb, huge_page_size(hstate_vma(vma))); +} + /** * tlb_finish_mmu - finish an mmu_gather structure * @tlb: the mmu_gather structure to finish @@ -468,6 +495,12 @@ 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/rmap.c b/mm/rmap.c index 748f48727a162..7b9879ef442d9 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_vma(&tlb, vma); + 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_vma(&tlb, vma); + 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

3 days, 4 hours

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[PATCH] io_uring: fix filename leak in __io_openat_prep()

by Prithvi Tambewagh

__io_openat_prep() allocates a struct filename using getname(), but it isn't freed in case the present file is installed in the fixed file table and simultaneously, it has the flag O_CLOEXEC set in the open->how.flags field. This is an erroneous condition, since for a file installed in the fixed file table, it won't be installed in the normal file table, due to which the file cannot support close on exec. Earlier, the code just returned -EINVAL error code for this condition, however, the memory allocated for that struct filename wasn't freed, resulting in a memory leak. Hence, the case of file being installed in the fixed file table as well as having O_CLOEXEC flag in open->how.flags set, is adressed by using putname() to release the memory allocated to the struct filename, then setting the field open->filename to NULL, and after that, returning -EINVAL. Reported-by: syzbot+00e61c43eb5e4740438f(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=00e61c43eb5e4740438f Tested-by: syzbot+00e61c43eb5e4740438f(a)syzkaller.appspotmail.com Cc: stable(a)vger.kernel.org Signed-off-by: Prithvi Tambewagh <activprithvi(a)gmail.com> --- io_uring/openclose.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/io_uring/openclose.c b/io_uring/openclose.c index bfeb91b31bba..fc190a3d8112 100644 --- a/io_uring/openclose.c +++ b/io_uring/openclose.c @@ -75,8 +75,11 @@ static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe } open->file_slot = READ_ONCE(sqe->file_index); - if (open->file_slot && (open->how.flags & O_CLOEXEC)) + if (open->file_slot && (open->how.flags & O_CLOEXEC)) { + putname(open->filename); + open->filename = NULL; return -EINVAL; + } open->nofile = rlimit(RLIMIT_NOFILE); req->flags |= REQ_F_NEED_CLEANUP; base-commit: b927546677c876e26eba308550207c2ddf812a43 -- 2.34.1

3 days, 6 hours

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[PATCH v2 0/2] hfsplus: avoid re-allocating header node 0 and stop on already-hashed nodes

by Shardul Bankar

Hi, syzbot reported a warning and crash when mounting a corrupted HFS+ image where the on-disk B-tree bitmap has node 0 (header node) marked free. In that case hfs_bmap_alloc() can try to allocate node 0 and reach hfs_bnode_create() with an already-hashed node number. Patch 1 prevents allocating the reserved header node (node 0) even if the bitmap is corrupted. Patch 2 follows Slava's review suggestion and changes the "already hashed" path in hfs_bnode_create() to return ERR_PTR(-EEXIST) instead of returning the existing node pointer, so we don't continue in a non-"business as usual" situation. v2 changes: - Implement Slava's suggestion: return ERR_PTR(-EEXIST) for already-hashed nodes. - Keep the node-0 allocation guard as a minimal, targeted hardening measure. Reported-by: syzbot+1c8ff72d0cd8a50dfeaa(a)syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=1c8ff72d0cd8a50dfeaa Link: https://lore.kernel.org/all/20251213233215.368558-1-shardul.b@mpiricsoftwar… Shardul Bankar (2): hfsplus: skip node 0 in hfs_bmap_alloc hfsplus: return error when node already exists in hfs_bnode_create fs/hfsplus/bnode.c | 2 +- fs/hfsplus/btree.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) -- 2.34.1

3 days, 7 hours

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[PATCH 0/4] mm/damon/sysfs: free setup failures generated zombie sub-sub dirs

by SeongJae Park

Some DAMON sysfs directory setup functions generates its sub and sub-sub directories. For example, 'monitoring_attrs/' directory setup creates 'intervals/' and 'intervals/intervals_goal/' directories under 'monitoring_attrs/' directory. When such sub-sub directories are successfully made but followup setup is failed, the setup function should recursively clean up the subdirectories. However, such setup functions are only dereferencing sub directory reference counters. As a result, under certain setup failures, the sub-sub directories keep having non-zero reference counters. It means the directories cannot be removed like zombies, and the memory for the directories cannot be freed. The user impact of this issue is limited due to the following reasons. When the issue happens, the zombie directories are still taking the path. Hence attempts to generate the directories again will fail, without additional memory leak. This means the upper bound memory leak is limited. Nonetheless this also implies controlling DAMON with a feature that requires the setup-failed sysfs files will be impossible until the system reboots. Also, the setup operations are quite simple. The certain failures would hence only rarely happen, and are difficult to artificially trigger. SeongJae Park (4): mm/damon/sysfs: cleanup intervals subdirs on attrs dir setup failure mm/damon/sysfs: cleanup attrs subdirs on context dir setup failure mm/damon/sysfs-scheme: cleanup quotas subdirs on scheme dir setup failure mm/damon/sysfs-scheme: cleanup access_pattern subdirs on scheme dir setup failure mm/damon/sysfs-schemes.c | 10 ++++++---- mm/damon/sysfs.c | 9 ++++++--- 2 files changed, 12 insertions(+), 7 deletions(-) base-commit: 6d039da6a260dd7919bebc70ebb65d250bb9c24e -- 2.47.3

3 days, 11 hours

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Fwd: Request to add mainline merged patch to stable kernels

by JP Dehollain

Hi Greg, thanks for looking into this.. The full commit hash is 807221d3c5ff6e3c91ff57bc82a0b7a541462e20 Note: apologies if you received this multiple times, the previous one got bounced due to html Cheers, JP ________________________________ From: Greg KH <gregkh(a)linuxfoundation.org> Sent: Tuesday, December 23, 2025 6:39:22 PM To: JP Dehollain <jpdehollain(a)gmail.com> Cc: stable(a)vger.kernel.org <stable(a)vger.kernel.org> Subject: Re: Request to add mainline merged patch to stable kernels On Tue, Dec 23, 2025 at 04:05:24PM +1100, JP Dehollain wrote: > Hello, > I recently used the patch misc: rtsx_pci: Add separate CD/WP pin > polarity reversal support with commit ID 807221d, to fix a bug causing > the cardreader driver to always load sd cards in read-only mode. > On the suggestion of the driver maintainer, I am requesting that this > patch be applied to all stable kernel versions, as it is currently > only applied to >=6.18. > Thanks, > JP > What is the git id of the commit you are looking to have backported? thanks, greg k-h

3 days, 16 hours

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[PATCH] ARM: dts: integrator: Fix DMA ranges mismatch warning on IM-PD1

by Kuan-Wei Chiu

When compiling the device tree for the Integrator/AP with IM-PD1, the following warning is observed regarding the display controller node: arch/arm/boot/dts/arm/integratorap-im-pd1.dts:251.3-14: Warning (dma_ranges_format): /bus@c0000000/bus@c0000000/display@1000000:dma-ranges: empty "dma-ranges" property but its #address-cells (2) differs from /bus@c0000000/bus@c0000000 (1) The display node specifies an empty "dma-ranges" property, intended to describe a 1:1 identity mapping. However, the node lacks explicit "#address-cells" and "#size-cells" properties. In this case, the device tree compiler defaults the address cells to 2 (64-bit), which conflicts with the parent bus configuration (32-bit, 1 cell). Fix this by explicitly defining "#address-cells" and "#size-cells" as 1. This matches the 32-bit architecture of the Integrator platform and ensures the address translation range is correctly parsed by the compiler. Fixes: 7bea67a99430 ("ARM: dts: integrator: Fix DMA ranges") Cc: stable(a)vger.kernel.org Signed-off-by: Kuan-Wei Chiu <visitorckw(a)gmail.com> --- arch/arm/boot/dts/arm/integratorap-im-pd1.dts | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm/boot/dts/arm/integratorap-im-pd1.dts b/arch/arm/boot/dts/arm/integratorap-im-pd1.dts index db13e09f2fab..6d90d9a42dc9 100644 --- a/arch/arm/boot/dts/arm/integratorap-im-pd1.dts +++ b/arch/arm/boot/dts/arm/integratorap-im-pd1.dts @@ -248,6 +248,8 @@ display@1000000 { /* 640x480 16bpp @ 25.175MHz is 36827428 bytes/s */ max-memory-bandwidth = <40000000>; memory-region = <&impd1_ram>; + #address-cells = <1>; + #size-cells = <1>; dma-ranges; port@0 { -- 2.52.0.177.g9f829587af-goog

3 days, 17 hours

3
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[PATCH v1 0/3] mm: mm_cid static initialization fixes

by Mathieu Desnoyers

Hi Andrew, Here are 2 fixes for missing mm_cid fields for init_mm and efi_mm static initialization. The renaming of cpu_bitmap to flexible_array (patch 2) is needed for patch 3. Those are relevant for mainline, with CC stable. They are based on v6.19-rc2. Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: stable(a)vger.kernel.org Cc: linux-mm(a)kvack.org Mathieu Desnoyers (3): mm: Add missing static initializer for init_mm::mm_cid.lock mm: Rename cpu_bitmap field to flexible_array mm: Take into account mm_cid size for mm_struct static definitions drivers/firmware/efi/efi.c | 2 +- include/linux/mm_types.h | 18 +++++++++++++----- mm/init-mm.c | 5 ++++- 3 files changed, 18 insertions(+), 7 deletions(-) -- 2.39.5

3 days, 20 hours

1
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[report] Performance regressions introduced via "cpuidle: menu: Remove iowait influence" on 6.12.y

by ALOK TIWARI

Hi, I’m reporting a performance regression of up to 6% sequential I/O vdbench regression observed on 6.12.y kernel. While running performance benchmarks on v6.12.60 kernel the sequential I/O vdbench metrics are showing a 5-6% performance regression when compared to v6.12.48 Bisect root cause commit ======================== - commit b39b62075ab4 ("cpuidle: menu: Remove iowait influence") Things work fine again when the previously removed performance-multiplier code is added back. Test details ============ The system is connected to a number of disks in disk array using multipathing and directio configuration in the vdbench profile. wd=wd1,sd=sd*,rdpct=0,seekpct=sequential,xfersize=128k rd=128k64T,wd=wd1,iorate=max,elapsed=600,interval=1,warmup=300,threads=64 Thanks, Alok

4 days

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