From d52008e48529bfb3ad9d223fb0a7d116baaef9c0 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 12 Mar 2013 15:36:00 -0700 Subject: cgroup: fix an off-by-one bug which may trigger BUG_ON() 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(-) (limited to 'kernel') diff --git a/kernel/cgroup.c b/kernel/cgroup.c index a32f9432666..55fca47e13d 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2065,7 +2065,7 @@ 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; -- cgit v1.2.3