Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751956AbdFIOXG (ORCPT ); Fri, 9 Jun 2017 10:23:06 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:60320 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751885AbdFIOWC (ORCPT ); Fri, 9 Jun 2017 10:22:02 -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, Matthew Wilcox 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 v4 12/20] mm/spf Protect vm_policy's changes against speculative pf Date: Fri, 9 Jun 2017 16:21:01 +0200 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1497018069-17790-1-git-send-email-ldufour@linux.vnet.ibm.com> References: <1497018069-17790-1-git-send-email-ldufour@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17060914-0016-0000-0000-000004B95418 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17060914-0017-0000-0000-000027E980E4 Message-Id: <1497018069-17790-13-git-send-email-ldufour@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-06-09_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1706090251 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1395 Lines: 48 Mark the VMA touched when policy changes are applied to it so that speculative page fault will be aborted. Signed-off-by: Laurent Dufour --- mm/mempolicy.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 13d32c25226c..5e44b3e69a0d 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -447,8 +447,11 @@ void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new) struct vm_area_struct *vma; down_write(&mm->mmap_sem); - for (vma = mm->mmap; vma; vma = vma->vm_next) + for (vma = mm->mmap; vma; vma = vma->vm_next) { + write_seqcount_begin(&vma->vm_sequence); mpol_rebind_policy(vma->vm_policy, new, MPOL_REBIND_ONCE); + write_seqcount_end(&vma->vm_sequence); + } up_write(&mm->mmap_sem); } @@ -711,6 +714,7 @@ static int vma_replace_policy(struct vm_area_struct *vma, if (IS_ERR(new)) return PTR_ERR(new); + write_seqcount_begin(&vma->vm_sequence); if (vma->vm_ops && vma->vm_ops->set_policy) { err = vma->vm_ops->set_policy(vma, new); if (err) @@ -719,10 +723,12 @@ static int vma_replace_policy(struct vm_area_struct *vma, old = vma->vm_policy; vma->vm_policy = new; /* protected by mmap_sem */ + write_seqcount_end(&vma->vm_sequence); mpol_put(old); return 0; err_out: + write_seqcount_end(&vma->vm_sequence); mpol_put(new); return err; } -- 2.7.4