From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Li Zefan , Tejun Heo Subject: [ 073/104] cgroup: fix an off-by-one bug which may trigger BUG_ON() Date: Mon, 6 May 2013 16:12:32 -0700 Message-Id: <20130506230051.132165514@linuxfoundation.org> In-Reply-To: <20130506230043.526528358@linuxfoundation.org> References: <20130506230043.526528358@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8-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: Greg Kroah-Hartman --- kernel/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2066,7 +2066,7 @@ static int cgroup_attach_proc(struct cgr 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;