Re: [PATCH 01/21] workqueue: fix race condition in schedule_on_each_cpu()

[Avi Kivity]

On 11/17/2009 01:04 AM, Frederic Weisbecker wrote:
> On Tue, Nov 17, 2009 at 02:15:06AM +0900, Tejun Heo wrote:
>    
> > Commit 65a64464349883891e21e74af16c05d6e1eeb4e9 which allows
> > schedule_on_each_cpu() to be called from keventd added a race
> > condition.  schedule_on_each_cpu() may race with cpu hotplug and end
> > up executing the function twice on a cpu.
> >
> > Fix it by moving direct execution into the section protected with
> > get/put_online_cpus().  While at it, update code such that direct
> > execution is done after works have been scheduled for all other cpus
> > and drop unnecessary cpu != orig test from flush loop.
> >
> > Signed-off-by: Tejun Heo<tj@xxxxxxxxxx>
> > Cc: Andi Kleen<ak@xxxxxxxxxxxxxxx>
> > Cc: Oleg Nesterov<oleg@xxxxxxxxxx>
> > ---
> >      
>
> Shouldn't this patch go to .32 ?
> This looks like an important fix.
>    

Is anything using preeempt notifier on affected architectures?

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/