Re: Kernel crash in icq_free_icq_rcu

[Vivek Goyal <vgoyal@redhat.com>]

On Tue, Jan 17, 2012 at 01:48:34PM -0800, Tejun Heo wrote:
> On Tue, Jan 17, 2012 at 03:18:23PM -0500, Vivek Goyal wrote:
> > Hi Tejun,
> > 
> > With latest linus kernel, I see following crash. I was running some
> > scripts which create cgroups and launch fio jobs in those groups. In
> > a separate window I wrote a script to change the IO scheduler on the
> > device in a loop while IO was happening on the device. After few
> > seconds I see following. So far I tried it twice and reproduced it
> > both the times in first few seconds.
> 
> Does the following patch make any difference?

Nope. Still can reproduce the issue.

Thanks
Vivek

> 
> diff --git a/block/elevator.c b/block/elevator.c
> index 91e18f8..b5a94ed 100644
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -105,6 +105,7 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio)
>  	if (bio_integrity(bio) != blk_integrity_rq(rq))
>  		return 0;
>  
> +	return 0;
>  	if (!elv_iosched_allow_merge(rq, bio))
>  		return 0;
>