* [PATCH net-next v2] bonding: fix system hang due to fast igmp timer rescheduling
@ 2013-07-30 23:44 Nikolay Aleksandrov
2013-08-01 0:05 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Nikolay Aleksandrov @ 2013-07-30 23:44 UTC (permalink / raw)
To: netdev; +Cc: andy, fubar, davem
From: "nikolay@redhat.com" <nikolay@redhat.com>
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 <nikolay@redhat.com>
---
v2: adjust bond_change_active_slave's mcast_work delay to 1 jiffy because
it's called with rtnl held most of the time as Jay suggested
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 da3af63..bc3578e 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);
}
}
--
1.8.1.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next v2] bonding: fix system hang due to fast igmp timer rescheduling
2013-07-30 23:44 [PATCH net-next v2] bonding: fix system hang due to fast igmp timer rescheduling Nikolay Aleksandrov
@ 2013-08-01 0:05 ` David Miller
2013-08-01 7:45 ` Nikolay Aleksandrov
0 siblings, 1 reply; 3+ messages in thread
From: David Miller @ 2013-08-01 0:05 UTC (permalink / raw)
To: nikolay; +Cc: netdev, andy, fubar
From: Nikolay Aleksandrov <nikolay@redhat.com>
Date: Wed, 31 Jul 2013 01:44:06 +0200
> From: "nikolay@redhat.com" <nikolay@redhat.com>
I don't think that "nikolay@redhat.com" is your name. :-)
Please fix this up and resubmit, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next v2] bonding: fix system hang due to fast igmp timer rescheduling
2013-08-01 0:05 ` David Miller
@ 2013-08-01 7:45 ` Nikolay Aleksandrov
0 siblings, 0 replies; 3+ messages in thread
From: Nikolay Aleksandrov @ 2013-08-01 7:45 UTC (permalink / raw)
To: David Miller; +Cc: netdev, andy, fubar
On 08/01/2013 02:05 AM, David Miller wrote:
> From: Nikolay Aleksandrov <nikolay@redhat.com>
> Date: Wed, 31 Jul 2013 01:44:06 +0200
>
>> From: "nikolay@redhat.com" <nikolay@redhat.com>
>
> I don't think that "nikolay@redhat.com" is your name. :-)
>
> Please fix this up and resubmit, thanks.
>
hehe nothing like a little git mess, will do. Thanks :-)
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-07-30 23:44 [PATCH net-next v2] bonding: fix system hang due to fast igmp timer rescheduling Nikolay Aleksandrov
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