From: Sha Zhengju <handai.szj@taobao.com>
Date: Thu, 3 May 2012 05:43:10 +0000 (+1000)
Subject: memcg: free spare array to avoid memory leak
X-Git-Tag: next-20120503~2^2~293
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a2733b9275c4f1de7e510365f0f967a92f757411;p=karo-tx-linux.git

memcg: free spare array to avoid memory leak

When the last event is unregistered, there is no need to keep the spare
array anymore.  So free it to avoid memory leak.

Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bdf43048e1e6..e379af2ce91f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4523,6 +4523,12 @@ static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
 swap_buffers:
 	/* Swap primary and spare array */
 	thresholds->spare = thresholds->primary;
+	/* If all events are unregistered, free the spare array */
+	if (!new) {
+		kfree(thresholds->spare);
+		thresholds->spare = NULL;
+	}
+
 	rcu_assign_pointer(thresholds->primary, new);
 
 	/* To be sure that nobody uses thresholds */