[PATCH 4.18 14/53] batman-adv: fix backbone_gw refcount on queue_work() failure

Greg Kroah-Hartman
2018-10-19T01:58:17Z

From: Marek Lindner <mareklindner@neomailbox.ch>

[ Upstream commit 5af96b9c59c72fb2af2d19c5cc2f3cdcee391dff ]

The backbone_gw refcounter is to be decreased by the queued work and
currently is never decreased if the queue_work() call fails.
Fix by checking the queue_work() return value and decrease refcount
if necessary.

Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/batman-adv/bridge_loop_avoidance.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -1772,6 +1772,7 @@ batadv_bla_loopdetect_check(struct batad
{
struct batadv_bla_backbone_gw *backbone_gw;
struct ethhdr *ethhdr;
+ bool ret;

ethhdr = eth_hdr(skb);

@@ -1795,8 +1796,13 @@ batadv_bla_loopdetect_check(struct batad
if (unlikely(!backbone_gw))
return true;

- queue_work(batadv_event_workqueue, &backbone_gw->report_work);
- /* backbone_gw is unreferenced in the report work function function */
+ ret = queue_work(batadv_event_workqueue, &backbone_gw->report_work);
+
+ /* backbone_gw is unreferenced in the report work function function
+ * if queue_work() call was successful
+ */
+ if (!ret)
+ batadv_backbone_gw_put(backbone_gw);

return true;
}