From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20130518021651.104994352@goodmis.org> Date: Fri, 17 May 2013 22:16:55 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Li Zefan , Tejun Heo Subject: [ 058/136 ] cgroup: fix an off-by-one bug which may trigger BUG_ON() References: <20130518021557.139113314@goodmis.org> Content-Disposition: inline; filename=0058-cgroup-fix-an-off-by-one-bug-which-may-trigger-BUG_O.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6.11.4 stable review patch. If anyone has any objections, please let me know. ------------------ From: Li Zefan [ Upstream commit 3ac1707a13a3da9cfc8f242a15b2fae6df2c5f88 ] 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 Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt --- kernel/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index ff2bce5..bfc0578 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2067,7 +2067,7 @@ 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; -- 1.7.10.4