[PATCH 067/118] cgroup: fix an off-by-one bug which may trigger BUG_ON()
Luis Henriques
luis.henriques at canonical.com
Tue May 7 13:38:33 UTC 2013
3.5.7.12 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Li Zefan <lizefan at 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 at huawei.com>
Signed-off-by: Tejun Heo <tj at kernel.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
kernel/cgroup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 87fbb45..5168e37 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2079,7 +2079,7 @@ 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;
--
1.8.1.2
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