[PATCH] cgroup: fix unbalanced locking

Zefan Li
2014-09-18T09:28:46Z

cgroup_pidlist_start() holds cgrp->pidlist_mutex and then calls
pidlist_array_load(), and cgroup_pidlist_stop() releases the mutex.

It is wrong that we release the mutex in the failure path in
pidlist_array_load(), because cgroup_pidlist_stop() will be called
no matter if cgroup_pidlist_start() returns errno or not.

Fixes: 4bac00d16a8760eae7205e41d2c246477d42a210
Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> # 3.14+
Signed-off-by: Zefan Li <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
kernel/cgroup.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2332efd..de70b63 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3970,7 +3970,6 @@ static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,

l = cgroup_pidlist_find_create(cgrp, type);
if (!l) {
- mutex_unlock(&cgrp->pidlist_mutex);
pidlist_free(array);
return -ENOMEM;
}
--
1.8.0.2