1 files changed, 4 insertions, 1 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index d2b88596efde..ca83b73fba19 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3708,8 +3708,10 @@ static void check_for_release(struct cgroup *cgrp)
 void __css_put(struct cgroup_subsys_state *css)
 {
         struct cgroup *cgrp = css->cgroup;
+        int val;
         rcu_read_lock();
-        if (atomic_dec_return(&css->refcnt) == 1) {
+        val = atomic_dec_return(&css->refcnt);
+        if (val == 1) {
                 if (notify_on_release(cgrp)) {
                         set_bit(CGRP_RELEASABLE, &cgrp->flags);
                         check_for_release(cgrp);
@@ -3717,6 +3719,7 @@ void __css_put(struct cgroup_subsys_state *css)
                 cgroup_wakeup_rmdir_waiter(cgrp);
         }
         rcu_read_unlock();
+        WARN_ON_ONCE(val < 1);
 }
 
 /*