From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz>, Andrea Arcangeli <aarcange@redhat.com>, Michal Hocko <mhocko@kernel.org>, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Subject: [PATCHv4 00/12] Do not lose dirty bit on THP pages Date: Wed, 13 Dec 2017 13:57:44 +0300 [thread overview] Message-ID: <20171213105756.69879-1-kirill.shutemov@linux.intel.com> (raw) Vlastimil noted that pmdp_invalidate() is not atomic and we can lose dirty and access bits if CPU sets them after pmdp dereference, but before set_pmd_at(). The bug can lead to data loss, but the race window is tiny and I haven't seen any reports that suggested that it happens in reality. So I don't think it worth sending it to stable. Unfortunately, there's no way to address the issue in a generic way. We need to fix all architectures that support THP one-by-one. All architectures that have THP supported have to provide atomic pmdp_invalidate() that returns previous value. If generic implementation of pmdp_invalidate() is used, architecture needs to provide atomic pmdp_estabish(). pmdp_estabish() is not used out-side generic implementation of pmdp_invalidate() so far, but I think this can change in the future. Aneesh Kumar K.V (2): powerpc/mm: update pmdp_invalidate to return old pmd value mm/thp: Remove pmd_huge_split_prepare Catalin Marinas (1): arm64: Provide pmdp_establish() helper Kirill A. Shutemov (7): asm-generic: Provide generic_pmdp_establish() arc: Use generic_pmdp_establish as pmdp_establish arm/mm: Provide pmdp_establish() helper mips: Use generic_pmdp_establish as pmdp_establish x86/mm: Provide pmdp_establish() helper mm: Do not lose dirty and access bits in pmdp_invalidate() mm: Use updated pmdp_invalidate() interface to track dirty/accessed bits Martin Schwidefsky (1): s390/mm: Modify pmdp_invalidate to return old value. Nitin Gupta (1): sparc64: Update pmdp_invalidate() to return old pmd value arch/arc/include/asm/hugepage.h | 3 + arch/arm/include/asm/pgtable-3level.h | 3 + arch/arm64/include/asm/pgtable.h | 7 +++ arch/mips/include/asm/pgtable.h | 3 + arch/powerpc/include/asm/book3s/64/hash-4k.h | 2 - arch/powerpc/include/asm/book3s/64/hash-64k.h | 2 - arch/powerpc/include/asm/book3s/64/pgtable.h | 13 +---- arch/powerpc/include/asm/book3s/64/radix.h | 6 -- arch/powerpc/mm/pgtable-book3s64.c | 7 ++- arch/powerpc/mm/pgtable-hash64.c | 22 ------- arch/s390/include/asm/pgtable.h | 4 +- arch/sparc/include/asm/pgtable_64.h | 2 +- arch/sparc/mm/tlb.c | 23 ++++++-- arch/x86/include/asm/pgtable-3level.h | 37 +++++++++++- arch/x86/include/asm/pgtable.h | 15 +++++ fs/proc/task_mmu.c | 8 +-- include/asm-generic/pgtable.h | 25 +++++--- mm/huge_memory.c | 83 ++++++++++++--------------- mm/pgtable-generic.c | 6 +- 19 files changed, 156 insertions(+), 115 deletions(-) -- 2.15.0
WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz>, Andrea Arcangeli <aarcange@redhat.com>, Michal Hocko <mhocko@kernel.org>, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Subject: [PATCHv4 00/12] Do not lose dirty bit on THP pages Date: Wed, 13 Dec 2017 13:57:44 +0300 [thread overview] Message-ID: <20171213105756.69879-1-kirill.shutemov@linux.intel.com> (raw) Vlastimil noted that pmdp_invalidate() is not atomic and we can lose dirty and access bits if CPU sets them after pmdp dereference, but before set_pmd_at(). The bug can lead to data loss, but the race window is tiny and I haven't seen any reports that suggested that it happens in reality. So I don't think it worth sending it to stable. Unfortunately, there's no way to address the issue in a generic way. We need to fix all architectures that support THP one-by-one. All architectures that have THP supported have to provide atomic pmdp_invalidate() that returns previous value. If generic implementation of pmdp_invalidate() is used, architecture needs to provide atomic pmdp_estabish(). pmdp_estabish() is not used out-side generic implementation of pmdp_invalidate() so far, but I think this can change in the future. Aneesh Kumar K.V (2): powerpc/mm: update pmdp_invalidate to return old pmd value mm/thp: Remove pmd_huge_split_prepare Catalin Marinas (1): arm64: Provide pmdp_establish() helper Kirill A. Shutemov (7): asm-generic: Provide generic_pmdp_establish() arc: Use generic_pmdp_establish as pmdp_establish arm/mm: Provide pmdp_establish() helper mips: Use generic_pmdp_establish as pmdp_establish x86/mm: Provide pmdp_establish() helper mm: Do not lose dirty and access bits in pmdp_invalidate() mm: Use updated pmdp_invalidate() interface to track dirty/accessed bits Martin Schwidefsky (1): s390/mm: Modify pmdp_invalidate to return old value. Nitin Gupta (1): sparc64: Update pmdp_invalidate() to return old pmd value arch/arc/include/asm/hugepage.h | 3 + arch/arm/include/asm/pgtable-3level.h | 3 + arch/arm64/include/asm/pgtable.h | 7 +++ arch/mips/include/asm/pgtable.h | 3 + arch/powerpc/include/asm/book3s/64/hash-4k.h | 2 - arch/powerpc/include/asm/book3s/64/hash-64k.h | 2 - arch/powerpc/include/asm/book3s/64/pgtable.h | 13 +---- arch/powerpc/include/asm/book3s/64/radix.h | 6 -- arch/powerpc/mm/pgtable-book3s64.c | 7 ++- arch/powerpc/mm/pgtable-hash64.c | 22 ------- arch/s390/include/asm/pgtable.h | 4 +- arch/sparc/include/asm/pgtable_64.h | 2 +- arch/sparc/mm/tlb.c | 23 ++++++-- arch/x86/include/asm/pgtable-3level.h | 37 +++++++++++- arch/x86/include/asm/pgtable.h | 15 +++++ fs/proc/task_mmu.c | 8 +-- include/asm-generic/pgtable.h | 25 +++++--- mm/huge_memory.c | 83 ++++++++++++--------------- mm/pgtable-generic.c | 6 +- 19 files changed, 156 insertions(+), 115 deletions(-) -- 2.15.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next reply other threads:[~2017-12-13 11:01 UTC|newest] Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-12-13 10:57 Kirill A. Shutemov [this message] 2017-12-13 10:57 ` [PATCHv4 00/12] Do not lose dirty bit on THP pages Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 01/12] asm-generic: Provide generic_pmdp_establish() Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 02/12] arc: Use generic_pmdp_establish as pmdp_establish Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 03/12] arm/mm: Provide pmdp_establish() helper Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 04/12] arm64: " Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 05/12] mips: Use generic_pmdp_establish as pmdp_establish Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 06/12] powerpc/mm: update pmdp_invalidate to return old pmd value Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 07/12] s390/mm: Modify pmdp_invalidate to return old value Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 08/12] sparc64: Update pmdp_invalidate() to return old pmd value Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-14 0:06 ` Andrew Morton 2017-12-14 0:06 ` Andrew Morton 2017-12-14 0:06 ` Andrew Morton 2017-12-13 10:57 ` [PATCHv4 09/12] x86/mm: Provide pmdp_establish() helper Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-14 0:09 ` Andrew Morton 2017-12-14 0:09 ` Andrew Morton 2017-12-14 0:33 ` Kirill A. Shutemov 2017-12-14 0:33 ` Kirill A. Shutemov 2017-12-14 0:36 ` Andrew Morton 2017-12-14 0:36 ` Andrew Morton 2017-12-14 0:42 ` Kirill A. Shutemov 2017-12-14 0:42 ` Kirill A. Shutemov 2017-12-15 13:49 ` Kirill A. Shutemov 2017-12-15 13:49 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 10/12] mm: Do not lose dirty and access bits in pmdp_invalidate() Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 11/12] mm: Use updated pmdp_invalidate() interface to track dirty/accessed bits Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov 2017-12-13 10:57 ` [PATCHv4 12/12] mm/thp: Remove pmd_huge_split_prepare Kirill A. Shutemov 2017-12-13 10:57 ` Kirill A. Shutemov
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