cgroup: fix missing unlock in cgroup_release_agent()

The patch 971ff4935538: "cgroup: use a per-cgroup work for release
agent" from Sep 18, 2014, leads to the following static checker
warning:

	kernel/cgroup.c:5310 cgroup_release_agent()
	warn: 'mutex:&cgroup_mutex' is sometimes locked here and sometimes unlocked.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 16e3a4f5c9dcd25cd0df399ed3b150214a0ceb31..f873c468131648fa422bdaab9adb2faf8230297c 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5291,7 +5291,10 @@ static void cgroup_release_agent(struct work_struct *work)
 
        mutex_unlock(&cgroup_mutex);
        call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+       goto out_free;
 out:
+       mutex_unlock(&cgroup_mutex);
+out_free:
        kfree(agentbuf);
        kfree(pathbuf);
 }