From: Liping Zhang <liping.zhang@spreadtrum.com>
Date: Thu, 21 Apr 2016 07:47:08 +0000 (-0700)
Subject: netfilter: IDLETIMER: fix race condition when destroy the target
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=cec5913c1515e5619907016658838af4eff78dd3;p=linux-beck.git

netfilter: IDLETIMER: fix race condition when destroy the target

Workqueue maybe still in running while we destroy the IDLETIMER target,
thus cause a use after free error, add cancel_work_sync() to avoid such
situation.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c
index 29d2c31f406c..daf45da448fa 100644
--- a/net/netfilter/xt_IDLETIMER.c
+++ b/net/netfilter/xt_IDLETIMER.c
@@ -236,6 +236,7 @@ static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
 
 		list_del(&info->timer->entry);
 		del_timer_sync(&info->timer->timer);
+		cancel_work_sync(&info->timer->work);
 		sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
 		kfree(info->timer->attr.attr.name);
 		kfree(info->timer);