| From | Greg Kroah-Hartman <> | Subject | [ 43/63] cgroup: fix an off-by-one bug which may trigger BUG_ON() | Date | Mon, 6 May 2013 15:56:21 -0700 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Li Zefan <lizefan@huawei.com>
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>
--- kernel/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2020,7 +2020,7 @@ 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;
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