From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752888AbdLMLB7 (ORCPT ); Wed, 13 Dec 2017 06:01:59 -0500 Received: from mga06.intel.com ([134.134.136.31]:37265 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751933AbdLMK6J (ORCPT ); Wed, 13 Dec 2017 05:58:09 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,397,1508828400"; d="scan'208";a="11936121" From: "Kirill A. Shutemov" To: Andrew Morton Cc: Vlastimil Babka , Andrea Arcangeli , Michal Hocko , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv4 00/12] Do not lose dirty bit on THP pages Date: Wed, 13 Dec 2017 13:57:44 +0300 Message-Id: <20171213105756.69879-1-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.15.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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