From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59674 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751598AbdJIM1V (ORCPT ); Mon, 9 Oct 2017 08:27:21 -0400 Subject: Patch "ksm: fix unlocked iteration over vmas in cmp_and_merge_page()" has been added to the 4.13-stable tree To: ktkhai@virtuozzo.com, aarcange@redhat.com, akpm@linux-foundation.org, gregkh@linuxfoundation.org, hughd@google.com, imbrenda@linux.vnet.ibm.com, kirill.shutemov@linux.intel.com, mhocko@suse.com, minchan@kernel.org, mingo@kernel.org, torvalds@linux-foundation.org, zhongjiang@huawei.com Cc: , From: Date: Mon, 09 Oct 2017 14:27:11 +0200 Message-ID: <150755203118179@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ksm: fix unlocked iteration over vmas in cmp_and_merge_page() to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ksm-fix-unlocked-iteration-over-vmas-in-cmp_and_merge_page.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 4b22927f0cbd58303aac689e378d20bf56267a39 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Tue, 3 Oct 2017 16:14:27 -0700 Subject: ksm: fix unlocked iteration over vmas in cmp_and_merge_page() From: Kirill Tkhai commit 4b22927f0cbd58303aac689e378d20bf56267a39 upstream. In this place mm is unlocked, so vmas or list may change. Down read mmap_sem to protect them from modifications. Link: http://lkml.kernel.org/r/150512788393.10691.8868381099691121308.stgit@localhost.localdomain Fixes: e86c59b1b12d ("mm/ksm: improve deduplication of zero pages with colouring") Signed-off-by: Kirill Tkhai Acked-by: Michal Hocko Reviewed-by: Andrea Arcangeli Cc: Minchan Kim Cc: zhong jiang Cc: Ingo Molnar Cc: Claudio Imbrenda Cc: "Kirill A. Shutemov" Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/ksm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1990,6 +1990,7 @@ static void stable_tree_append(struct rm */ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item) { + struct mm_struct *mm = rmap_item->mm; struct rmap_item *tree_rmap_item; struct page *tree_page = NULL; struct stable_node *stable_node; @@ -2062,9 +2063,11 @@ static void cmp_and_merge_page(struct pa if (ksm_use_zero_pages && (checksum == zero_checksum)) { struct vm_area_struct *vma; - vma = find_mergeable_vma(rmap_item->mm, rmap_item->address); + down_read(&mm->mmap_sem); + vma = find_mergeable_vma(mm, rmap_item->address); err = try_to_merge_one_page(vma, page, ZERO_PAGE(rmap_item->address)); + up_read(&mm->mmap_sem); /* * In case of failure, the page was not really empty, so we * need to continue. Otherwise we're done. Patches currently in stable-queue which might be from ktkhai@virtuozzo.com are queue-4.13/ksm-fix-unlocked-iteration-over-vmas-in-cmp_and_merge_page.patch