Re: WARNING: at block/genhd.c:1556 disk_clear_events+0xdc/0xf0()

[Tejun Heo <tj@kernel.org>]

On Thu, Apr 21, 2011 at 08:43:04PM +0200, Tejun Heo wrote:
> On Thu, Apr 21, 2011 at 07:38:45PM +0200, Tejun Heo wrote:
> > Hello,
> > 
> > On Fri, Apr 15, 2011 at 10:41:40PM +0100, Sitsofe Wheeler wrote:
> > > I couldn't reproduce the problem with the very latest kernel but here's
> > > the output that appeared with an older kernel with your patch:
> > > 
> > > ------------[ cut here ]------------
> > > WARNING: at block/genhd.c:1561 disk_clear_events+0x164/0x170()
> > 
> > Hmmm... that's really weird.  It indicates that the workqueue command
> > sequence there doesn't guarantee scheduling and completion of the work
> > item, which means either there's a bug in workqueue itself or I'm
> > confused about what's going on.  Hopefully, the latter.
> > Unfortunately, even with physical setup, I'm having problem
> > reproducing the problem.  Which kernel version are you using exactly?
> > Can you please let me know the commit ID?
> 
> Also, please try the following patch.  It should show what's going on
> with the flush machinery.

Never mind.  I now have a reliably reproducible test case.  Can you
please add yourself to bug 34662?  Let's track this issue there.

 https://bugzilla.kernel.org/show_bug.cgi?id=34662

Thanks.

-- 
tejun