From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Aleksandrov Subject: [PATCH net-next] bonding: fix system hang due to fast igmp timer rescheduling Date: Tue, 30 Jul 2013 19:37:32 +0200 Message-ID: <1375205852-31325-1-git-send-email-nikolay@redhat.com> Cc: andy@greyhouse.net, fubar@us.ibm.com To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:1310 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751725Ab3G3RlI (ORCPT ); Tue, 30 Jul 2013 13:41:08 -0400 Sender: netdev-owner@vger.kernel.org List-ID: From: Nikolay Aleksandrov 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. Signed-off-by: Nikolay Aleksandrov --- drivers/net/bonding/bond_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index da3af63..9d94313 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); -- 1.8.1.4