From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id CB1546B0397 for ; Thu, 27 Apr 2017 11:53:33 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id c198so29182644pfc.19 for ; Thu, 27 Apr 2017 08:53:33 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id d7si196985pfa.409.2017.04.27.08.53.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Apr 2017 08:53:32 -0700 (PDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v3RFmtxa075677 for ; Thu, 27 Apr 2017 11:53:32 -0400 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0a-001b2d01.pphosted.com with ESMTP id 2a3jbcvbn9-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 27 Apr 2017 11:53:31 -0400 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 27 Apr 2017 16:53:29 +0100 From: Laurent Dufour Subject: [RFC v3 17/17] mm/spf: protect mremap() against speculative pf Date: Thu, 27 Apr 2017 17:52:56 +0200 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> Message-Id: <1493308376-23851-18-git-send-email-ldufour@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: 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 mremap() is modifying the VMA layout and thus must be protected against the speculative page fault handler. XXX: Is the change to vma->vm_flags to set VM_ACCOUNT require the protection ? 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 30d7d2482eea..40c3c869dffc 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -288,6 +288,10 @@ 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) { @@ -304,6 +308,7 @@ 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; @@ -311,7 +316,9 @@ static unsigned long move_vma(struct vm_area_struct *vma, } else { 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org