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authorLi Zefan <lizefan@huawei.com>2013-03-12 15:36:00 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-07 20:33:11 -0700
commitd52008e48529bfb3ad9d223fb0a7d116baaef9c0 (patch)
treeac211a32a5282629e0dbbac3a808bfcc714270ee
parent0252cb3cc34d02ffb9ff835488a805030d3ef435 (diff)
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 <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/cgroup.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a32f9432666c..55fca47e13d6 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;