From 3ac1707a13a3da9cfc8f242a15b2fae6df2c5f88 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 12 Mar 2013 15:36:00 -0700 Subject: [PATCH] cgroup: fix an off-by-one bug which may trigger BUG_ON() 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 --- kernel/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c7fe303b5109..54689fc008f6 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2076,7 +2076,7 @@ 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; -- 2.20.1