Re: Linux 3.0 release

From: Francois Romieu
Date: Fri Jul 22 2011 - 17:43:06 EST


Stephen Hemminger <shemminger@xxxxxxxxxx> :
> This a regression which probably began with
>
> commit e22bee782b3b00bd4534ae9b1c5fb2e8e6573c5c
> Author: Tejun Heo <tj@xxxxxxxxxx>
> Date: Tue Jun 29 10:07:14 2010 +0200
>
> workqueue: implement concurrency managed dynamic worker pool
>
> Before that it was perfectly legal for link watch code to
> call schedule_delayed_work from IRQ. This should be allowable;
> the code to manage the worker pool should handle it.

I beg to differ: see Ben's first report
(http://lists.openwall.net/netdev/2011/05/04/183).
^^

One of the code path in the netif_carrier code leads it to try and disable
a late workqueue to reenable it immediately (mod_workqueue anyone ?):
netif_carrier_on
-> linkwatch_fire_event
-> linkwatch_schedule_work
-> cancel_delayed_work
-> del_timer_sync

The del_timer_sync has been here for ages. Afaiks it is not a new pool code
nor a schedule_delayed_work only problem.

--
Ueimor
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