From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753670AbeE3Ll6 (ORCPT ); Wed, 30 May 2018 07:41:58 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:60707 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752102AbeE3LG7 (ORCPT ); Wed, 30 May 2018 07:06:59 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Michal Hocko" , "Dmitriy Vyukov" , "Yisheng Xie" , "Linus Torvalds" , "Vlastimil Babka" , "Alexander Potapenko" Date: Wed, 30 May 2018 11:52:42 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 142/153] mm/mempolicy.c: avoid use uninitialized preferred_node In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.102-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Yisheng Xie commit 8970a63e965b43288c4f5f40efbc2bbf80de7f16 upstream. Alexander reported a use of uninitialized memory in __mpol_equal(), which is caused by incorrect use of preferred_node. When mempolicy in mode MPOL_PREFERRED with flags MPOL_F_LOCAL, it uses numa_node_id() instead of preferred_node, however, __mpol_equal() uses preferred_node without checking whether it is MPOL_F_LOCAL or not. [akpm@linux-foundation.org: slight comment tweak] Link: http://lkml.kernel.org/r/4ebee1c2-57f6-bcb8-0e2d-1833d1ee0bb7@huawei.com Fixes: fc36b8d3d819 ("mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy") Signed-off-by: Yisheng Xie Reported-by: Alexander Potapenko Tested-by: Alexander Potapenko Reviewed-by: Andrew Morton Cc: Dmitriy Vyukov Cc: Vlastimil Babka Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- mm/mempolicy.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2019,6 +2019,9 @@ int __mpol_equal(struct mempolicy *a, st case MPOL_INTERLEAVE: return nodes_equal(a->v.nodes, b->v.nodes); case MPOL_PREFERRED: + /* a's ->flags is the same as b's */ + if (a->flags & MPOL_F_LOCAL) + return true; return a->v.preferred_node == b->v.preferred_node; default: BUG();