netdev - [PATCH 2/3] netfilter: IDLETIMER: fix race condition when destroy the target

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Message-Id: <1462823523-6682-3-git-send-email-pablo@netfilter.org>
Date:	Mon,  9 May 2016 21:52:02 +0200
From:	Pablo Neira Ayuso <pablo@...filter.org>
To:	netfilter-devel@...r.kernel.org
Cc:	davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 2/3] netfilter: IDLETIMER: fix race condition when destroy the target

From: Liping Zhang <liping.zhang@...eadtrum.com>

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@...eadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/xt_IDLETIMER.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c
index 29d2c31..daf45da 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);
-- 
2.1.4