Re: bio linked list corruption.

[Jens Axboe]

On 10/26/2016 05:19 PM, Chris Mason wrote:
> On Wed, Oct 26, 2016 at 05:03:45PM -0600, Jens Axboe wrote:
> > On 10/26/2016 04:58 PM, Linus Torvalds wrote:
> > > On Wed, Oct 26, 2016 at 3:51 PM, Linus Torvalds
> > > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > > > Dave: it might be a good idea to split that "WARN_ON_ONCE()" in
> > > > blk_mq_merge_queue_io() into two
> > >
> > > I did that myself too, since Dave sees this during boot.
> > >
> > > But I'm not getting the warning ;(
> > >
> > > Dave gets it with ext4, and thats' what I have too, so I'm not sure
> > > what the required trigger would be.
> >
> > Actually, I think I see what might trigger it. You are on nvme, iirc,
> > and that has a deep queue. Dave, are you testing on a sata drive or
> > something similar with a shallower queue depth? If we end up sleeping
> > for a request, I think we could trigger data->ctx being different.
> >
> > Dave, can you hit the warnings with this? Totally untested...
>
> Confirmed, totally untested ;)  Don't try this one at home folks
> (working this out with Jens offlist)

Ahem, I did say untested! The one I just sent in reply to Linus should
be better. Though that one is completely untested as well...

--
Jens Axboe