[PATCH 062/100] ipv4 igmp: use in_dev_put in timer handlers instead of __in_dev_put

[Luis Henriques]

3.5.7.23 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Salam Noureddine <noureddine at aristanetworks.com>

commit e2401654dd0f5f3fb7a8d80dad9554d73d7ca394 upstream.

It is possible for the timer handlers to run after the call to
ip_mc_down so use in_dev_put instead of __in_dev_put in the handler
function in order to do proper cleanup when the refcnt reaches 0.
Otherwise, the refcnt can reach zero without the in_device being
destroyed and we end up leaking a reference to the net_device and
see messages like the following,

unregister_netdevice: waiting for eth0 to become free. Usage count = 1

Tested on linux-3.4.43.

Signed-off-by: Salam Noureddine <noureddine at aristanetworks.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/ipv4/igmp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index ca66431..be7dba8 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -709,7 +709,7 @@ static void igmp_gq_timer_expire(unsigned long data)
 
 	in_dev->mr_gq_running = 0;
 	igmpv3_send_report(in_dev, NULL);
-	__in_dev_put(in_dev);
+	in_dev_put(in_dev);
 }
 
 static void igmp_ifc_timer_expire(unsigned long data)
@@ -721,7 +721,7 @@ static void igmp_ifc_timer_expire(unsigned long data)
 		in_dev->mr_ifc_count--;
 		igmp_ifc_start_timer(in_dev, IGMP_Unsolicited_Report_Interval);
 	}
-	__in_dev_put(in_dev);
+	in_dev_put(in_dev);
 }
 
 static void igmp_ifc_event(struct in_device *in_dev)
-- 
1.8.3.2