Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751829AbdILPk3 (ORCPT ); Tue, 12 Sep 2017 11:40:29 -0400 Received: from mga06.intel.com ([134.134.136.31]:37979 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751778AbdILPkW (ORCPT ); Tue, 12 Sep 2017 11:40:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,383,1500966000"; d="scan'208";a="1194271778" From: "Kirill A. Shutemov" To: Andrew Morton , Vlastimil Babka , Vineet Gupta , Russell King , Will Deacon , Catalin Marinas , Ralf Baechle , "David S. Miller" , "Aneesh Kumar K . V" , Martin Schwidefsky , Heiko Carstens , Andrea Arcangeli Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv3 00/11] Do not loose dirty bit on THP pages Date: Tue, 12 Sep 2017 18:39:30 +0300 Message-Id: <20170912153941.47012-1-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.14.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2496 Lines: 59 Vlastimil noted that pmdp_invalidate() is not atomic and we can loose 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 sparc64: update pmdp_invalidate to return old pmd value 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 loose 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. 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/pgtable.h | 4 +-- arch/powerpc/mm/pgtable-book3s64.c | 7 ++++-- arch/s390/include/asm/pgtable.h | 5 ++-- 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 | 17 ++++++++++++- mm/huge_memory.c | 29 +++++++++------------- mm/pgtable-generic.c | 6 ++--- 15 files changed, 131 insertions(+), 38 deletions(-) -- 2.14.1