From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754651AbdBGOHj (ORCPT ); Tue, 7 Feb 2017 09:07:39 -0500 Received: from mail-wm0-f53.google.com ([74.125.82.53]:35567 "EHLO mail-wm0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754088AbdBGOHg (ORCPT ); Tue, 7 Feb 2017 09:07:36 -0500 From: Sean Rees To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, thgarnie@google.com, Sean Rees Subject: [PATCH] mm/slub: Fix random_seq offset destruction Date: Tue, 7 Feb 2017 14:07:07 +0000 Message-Id: <20170207140707.20824-1-sean@erifax.org> X-Mailer: git-send-email 2.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Bailout early from init_cache_random_seq if s->random_seq is already initialised. This prevents destroying the previously computed random_seq offsets later in the function. If the offsets are destroyed, then shuffle_freelist will truncate page->freelist to just the first object (orphaning the rest). This fixes https://bugzilla.kernel.org/show_bug.cgi?id=177551. Signed-off-by: Sean Rees --- mm/slub.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index 7aa6f43..7ec0a96 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1422,6 +1422,10 @@ static int init_cache_random_seq(struct kmem_cache *s) int err; unsigned long i, count = oo_objects(s->oo); + /* Bailout if already initialised */ + if (s->random_seq) + return 0; + err = cache_random_seq_create(s, count, GFP_KERNEL); if (err) { pr_err("SLUB: Unable to initialize free list for %s\n", -- 2.9.3