ipv6 mcast: use in6_dev_put in timer handlers instead of __in6_dev_put

It is possible for the timer handlers to run after the call to
ipv6_mc_down so use in6_dev_put instead of __in6_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
inet6_dev 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@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 096cd67b737c4b4eba2d42470d7a58e2e229153c..d18f9f903db62333983d3fad0e1ccb9298762c98 100644 (file)
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -2034,7 +2034,7 @@ static void mld_dad_timer_expire(unsigned long data)
                if (idev->mc_dad_count)
                        mld_dad_start_timer(idev, idev->mc_maxdelay);
        }
-       __in6_dev_put(idev);
+       in6_dev_put(idev);
 }
 
 static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
@@ -2379,7 +2379,7 @@ static void mld_gq_timer_expire(unsigned long data)
 
        idev->mc_gq_running = 0;
        mld_send_report(idev, NULL);
-       __in6_dev_put(idev);
+       in6_dev_put(idev);
 }
 
 static void mld_ifc_timer_expire(unsigned long data)
@@ -2392,7 +2392,7 @@ static void mld_ifc_timer_expire(unsigned long data)
                if (idev->mc_ifc_count)
                        mld_ifc_start_timer(idev, idev->mc_maxdelay);
        }
-       __in6_dev_put(idev);
+       in6_dev_put(idev);
 }
 
 static void mld_ifc_event(struct inet6_dev *idev)