Re: [Qemu-block] [PATCH] virtio-blk: assert on starting/stopping

[Michael S. Tsirkin]

On Mon, Apr 04, 2016 at 10:25:34AM +0200, Cornelia Huck wrote:
> On Mon, 4 Apr 2016 10:19:42 +0200
> Paolo Bonzini <address@hidden> wrote:
> 
> > On 04/04/2016 10:10, Cornelia Huck wrote:
> > > > This will be fixed by Cornelia's rework, and is an example of why I
> > > > think patch 1/9 is a good idea (IOW, assign=false is harmful).
> > > 
> > > So what do we want to do for 2.6? The aio handler rework (without the
> > > cleanup) is needed. Do we want to include the minimal version of my
> > > "keep handler assigned" patch (the one without the api rework) as well,
> > > as it fixes a latent bug?
> > 
> > I would, but Michael is more conservative in general.  Since the
> > difference between a bug and a feature is very fuzzy here, I would just
> > omit my patch 9.
> 
> I'd omit patch 9 as well, but the knowledge that the "handler
> deassigned" bug is still lurking makes me uncomfortable.

It's not a bug as such - that logic was relying on handler
invoking itself being a nop and that assumption broke with
dataplane rework.

> Would like to see a test from someone with a large setup, anyway (and I
> need to enhance my test setup, I guess...)

Now that Christian sent the backtrace I feel with understand
the issues, but more testing is always good :)

-- 
MST