From: Greg Kroah-Hartman Date: Wed, 24 Nov 2021 11:14:06 +0000 (+0100) Subject: 4.4-stable patches X-Git-Tag: v5.15.5~18 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=52b6d4e07cf105c867985f361c37c1677c1dcad2;p=thirdparty%2Fkernel%2Fstable-queue.git 4.4-stable patches added patches: hugetlbfs-flush-tlbs-correctly-after-huge_pmd_unshare.patch --- diff --git a/queue-4.4/hugetlbfs-flush-tlbs-correctly-after-huge_pmd_unshare.patch b/queue-4.4/hugetlbfs-flush-tlbs-correctly-after-huge_pmd_unshare.patch new file mode 100644 index 00000000000..57fc0c1c41e --- /dev/null +++ b/queue-4.4/hugetlbfs-flush-tlbs-correctly-after-huge_pmd_unshare.patch @@ -0,0 +1,70 @@ +From a4a118f2eead1d6c49e00765de89878288d4b890 Mon Sep 17 00:00:00 2001 +From: Nadav Amit +Date: Sun, 21 Nov 2021 12:40:07 -0800 +Subject: hugetlbfs: flush TLBs correctly after huge_pmd_unshare + +From: Nadav Amit + +commit a4a118f2eead1d6c49e00765de89878288d4b890 upstream. + +When __unmap_hugepage_range() calls to huge_pmd_unshare() succeed, a TLB +flush is missing. This TLB flush must be performed before releasing the +i_mmap_rwsem, in order to prevent an unshared PMDs page from being +released and reused before the TLB flush took place. + +Arguably, a comprehensive solution would use mmu_gather interface to +batch the TLB flushes and the PMDs page release, however it is not an +easy solution: (1) try_to_unmap_one() and try_to_migrate_one() also call +huge_pmd_unshare() and they cannot use the mmu_gather interface; and (2) +deferring the release of the page reference for the PMDs page until +after i_mmap_rwsem is dropeed can confuse huge_pmd_unshare() into +thinking PMDs are shared when they are not. + +Fix __unmap_hugepage_range() by adding the missing TLB flush, and +forcing a flush when unshare is successful. + +Fixes: 24669e58477e ("hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages)" # 3.6 +Signed-off-by: Nadav Amit +Reviewed-by: Mike Kravetz +Cc: Aneesh Kumar K.V +Cc: KAMEZAWA Hiroyuki +Cc: Andrew Morton +Signed-off-by: Linus Torvalds +Signed-off-by: Greg Kroah-Hartman + +--- + include/asm-generic/tlb.h | 7 +++++++ + mm/hugetlb.c | 5 ++++- + 2 files changed, 11 insertions(+), 1 deletion(-) + +--- a/include/asm-generic/tlb.h ++++ b/include/asm-generic/tlb.h +@@ -165,6 +165,13 @@ static inline void __tlb_reset_range(str + #define tlb_end_vma __tlb_end_vma + #endif + ++static inline void tlb_flush_pmd_range(struct mmu_gather *tlb, ++ unsigned long address, unsigned long size) ++{ ++ tlb->start = min(tlb->start, address); ++ tlb->end = max(tlb->end, address + size); ++} ++ + #ifndef __tlb_remove_tlb_entry + #define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0) + #endif +--- a/mm/hugetlb.c ++++ b/mm/hugetlb.c +@@ -3290,8 +3290,11 @@ again: + continue; + + ptl = huge_pte_lock(h, mm, ptep); +- if (huge_pmd_unshare(mm, &address, ptep)) ++ if (huge_pmd_unshare(mm, &address, ptep)) { ++ tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE); ++ force_flush = 1; + goto unlock; ++ } + + pte = huge_ptep_get(ptep); + if (huge_pte_none(pte)) diff --git a/queue-4.4/series b/queue-4.4/series index 6e54e79d783..bfa75ffc36e 100644 --- a/queue-4.4/series +++ b/queue-4.4/series @@ -159,3 +159,4 @@ batman-adv-don-t-always-reallocate-the-fragmentation-skb-head.patch batman-adv-avoid-warn_on-timing-related-checks.patch asoc-dapm-cover-regression-by-kctl-change-notification-fix.patch usb-max-3421-use-driver-data-instead-of-maintaining-a-list-of-bound-devices.patch +hugetlbfs-flush-tlbs-correctly-after-huge_pmd_unshare.patch