From 4beac0293fabb68125e1a9d2ce81d89343f8702d Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Thu, 1 Aug 2013 11:51:42 +0200 Subject: [PATCH] bonding: fix system hang due to fast igmp timer rescheduling After commit 4aa5dee4d9 ("net: convert resend IGMP to notifier event") we try to acquire rtnl in bond_resend_igmp_join_requests but it can be scheduled with rtnl already held (e.g. when bond_change_active_slave is called with rtnl) causing a loop of immediate reschedules + calls because rtnl_trylock fails each time since it's being already held. For me this issue leads to system hangs very easy: modprobe bonding; ifconfig bond0 up; ifenslave bond0 eth0; rmmod bonding; The fix is to introduce a small (1 jiffy) delay which is enough for the sections holding rtnl to finish without putting any strain on the system. Also adjust the timer in bond_change_active_slave to be 1 jiffy, since most of the time it's called with rtnl already held. Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index da3af631f21b..bc3578e4980a 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -723,7 +723,7 @@ static int bond_set_allmulti(struct bonding *bond, int inc) static void bond_resend_igmp_join_requests(struct bonding *bond) { if (!rtnl_trylock()) { - queue_delayed_work(bond->wq, &bond->mcast_work, 0); + queue_delayed_work(bond->wq, &bond->mcast_work, 1); return; } call_netdevice_notifiers(NETDEV_RESEND_IGMP, bond->dev); @@ -1084,7 +1084,7 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active) ((USES_PRIMARY(bond->params.mode) && new_active) || bond->params.mode == BOND_MODE_ROUNDROBIN)) { bond->igmp_retrans = bond->params.resend_igmp; - queue_delayed_work(bond->wq, &bond->mcast_work, 0); + queue_delayed_work(bond->wq, &bond->mcast_work, 1); } } -- 2.20.1