Re: block: WARN_ON_ONCE(ev->block <= 0) triggered in__disk_unblock_events()

From: Tejun Heo
Date: Tue Jan 03 2012 - 13:37:44 EST


Hello,

On Sun, Jan 01, 2012 at 05:22:58PM +0000, Bart Van Assche wrote:
> In a workload that involves a lot of scsi_remove_hosts() calls (srp-ha
> patch set stress test) I get the call stack below after about 30 to 50
> iterations. Is this a known issue ? Does this indicate a race
> condition in the block layer ? I can trigger this issue not only with
> 3.2-rc7 but also with 3.1.6. I haven't tried any other kernel versions
> yet.
>
> ------------[ cut here ]------------
> WARNING: at block/genhd.c:1466 __disk_unblock_events+0xf5/0x110()

It's indicating that there were more disk_unblock_events() than
disk_block_events(). Hmmm... weird. I'll prep a debug patch.

Thanks.

--
tejun
--
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/