From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933180Ab3EGNlt (ORCPT ); Tue, 7 May 2013 09:41:49 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:42404 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933115Ab3EGNln (ORCPT ); Tue, 7 May 2013 09:41:43 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Li Zefan , Tejun Heo , Luis Henriques Subject: [PATCH 067/118] cgroup: fix an off-by-one bug which may trigger BUG_ON() Date: Tue, 7 May 2013 14:38:33 +0100 Message-Id: <1367933964-1564-68-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1367933964-1564-1-git-send-email-luis.henriques@canonical.com> References: <1367933964-1564-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.12 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Li Zefan commit 3ac1707a13a3da9cfc8f242a15b2fae6df2c5f88 upstream. The 3rd parameter of flex_array_prealloc() is the number of elements, not the index of the last element. The effect of the bug is, when opening cgroup.procs, a flex array will be allocated and all elements of the array is allocated with GFP_KERNEL flag, but the last one is GFP_ATOMIC, and if we fail to allocate memory for it, it'll trigger a BUG_ON(). Signed-off-by: Li Zefan Signed-off-by: Tejun Heo Signed-off-by: Luis Henriques --- kernel/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 87fbb45..5168e37 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2079,7 +2079,7 @@ static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) if (!group) return -ENOMEM; /* pre-allocate to guarantee space while iterating in rcu read-side. */ - retval = flex_array_prealloc(group, 0, group_size - 1, GFP_KERNEL); + retval = flex_array_prealloc(group, 0, group_size, GFP_KERNEL); if (retval) goto out_free_group_list; -- 1.8.1.2