Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162901AbdD0Pzl (ORCPT ); Thu, 27 Apr 2017 11:55:41 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44918 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1033868AbdD0Pxh (ORCPT ); Thu, 27 Apr 2017 11:53:37 -0400 From: Laurent Dufour To: paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com Subject: [RFC v3 16/17] mm: protect madvise vs speculative pf Date: Thu, 27 Apr 2017 17:52:55 +0200 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1493308376-23851-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1493308376-23851-1-git-send-email-ldufour@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17042715-0040-0000-0000-00000397040F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17042715-0041-0000-0000-00001FE4965C Message-Id: <1493308376-23851-17-git-send-email-ldufour@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-27_14:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1704270259 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1027 Lines: 37 This is an attempt to protect madvise's effect against the speculative page fault handler. Signed-off-by: Laurent Dufour --- mm/madvise.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/madvise.c b/mm/madvise.c index 0e3828eae9f8..f91b64564571 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -132,8 +132,9 @@ static long madvise_behavior(struct vm_area_struct *vma, /* * vm_flags is protected by the mmap_sem held in write mode. */ + write_seqcount_begin(&vma->vm_sequence); vma->vm_flags = new_flags; - + write_seqcount_end(&vma->vm_sequence); out: if (error == -ENOMEM) error = -EAGAIN; @@ -403,9 +404,11 @@ static void madvise_free_page_range(struct mmu_gather *tlb, .private = tlb, }; + write_seqcount_begin(&vma->vm_sequence); tlb_start_vma(tlb, vma); walk_page_range(addr, end, &free_walk); tlb_end_vma(tlb, vma); + write_seqcount_end(&vma->vm_sequence); } static int madvise_free_single_vma(struct vm_area_struct *vma, -- 2.7.4