From: Tejun Heo <tj@kernel.org>
Date: Tue, 13 May 2014 15:28:30 +0000 (-0400)
Subject: cgroup: fix rcu_read_lock() leak in update_if_frozen()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=36e9d2ebcc15d029b33f42a36146ab5a5bcfcfe7;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

cgroup: fix rcu_read_lock() leak in update_if_frozen()

While updating cgroup_freezer locking, 68fafb77d827 ("cgroup_freezer:
replace freezer->lock with freezer_mutex") introduced a bug in
update_if_frozen() where it returns with rcu_read_lock() held.  Fix it
by adding rcu_read_unlock() before returning.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
---

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 12ead0b766ee..345628c78b5b 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -267,8 +267,10 @@ static void update_if_frozen(struct cgroup_subsys_state *css)
 		struct freezer *child = css_freezer(pos);
 
 		if ((child->state & CGROUP_FREEZER_ONLINE) &&
-		    !(child->state & CGROUP_FROZEN))
+		    !(child->state & CGROUP_FROZEN)) {
+			rcu_read_unlock();
 			return;
+		}
 	}
 	rcu_read_unlock();