Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751869AbdFIOV6 (ORCPT ); Fri, 9 Jun 2017 10:21:58 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53811 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751608AbdFIOVy (ORCPT ); Fri, 9 Jun 2017 10:21:54 -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 15/20] mm/spf: protect mremap() against speculative pf Date: Fri, 9 Jun 2017 16:21:04 +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: 17060914-0012-0000-0000-0000054950F6 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17060914-0013-0000-0000-000018B88400 Message-Id: <1497018069-17790-16-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: 1391 Lines: 43 mremap() is modifying the VMA layout and thus must be protected against the speculative page fault handler. Signed-off-by: Laurent Dufour --- mm/mremap.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/mremap.c b/mm/mremap.c index cd8a1b199ef9..9c7f69c9e80f 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -300,6 +300,10 @@ static unsigned long move_vma(struct vm_area_struct *vma, if (!new_vma) return -ENOMEM; + write_seqcount_begin(&vma->vm_sequence); + write_seqcount_begin_nested(&new_vma->vm_sequence, + SINGLE_DEPTH_NESTING); + moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len, need_rmap_locks); if (moved_len < old_len) { @@ -316,6 +320,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, */ move_page_tables(new_vma, new_addr, vma, old_addr, moved_len, true); + write_seqcount_end(&vma->vm_sequence); vma = new_vma; old_len = new_len; old_addr = new_addr; @@ -324,7 +329,9 @@ static unsigned long move_vma(struct vm_area_struct *vma, mremap_userfaultfd_prep(new_vma, uf); arch_remap(mm, old_addr, old_addr + old_len, new_addr, new_addr + new_len); + write_seqcount_end(&vma->vm_sequence); } + write_seqcount_end(&new_vma->vm_sequence); /* Conceal VM_ACCOUNT so old reservation is not undone */ if (vm_flags & VM_ACCOUNT) { -- 2.7.4