Re: blktests failures with v5.19-rc1

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Jul 19, 2022 at 04:50:36AM +0000, Shinichiro Kawasaki wrote:
> On Jun 15, 2022 / 17:16, Keith Busch wrote:
> > On Wed, Jun 15, 2022 at 02:47:27PM -0500, Bjorn Helgaas wrote:
> > > On Tue, Jun 14, 2022 at 04:00:45AM +0000, Shinichiro Kawasaki wrote:
> > > > 
> > > > Yeah, this WARN is confusing for us then it would be valuable to
> > > > test by blktests not to repeat it. One point I wonder is: which test
> > > > group the test case will it fall in? The nvme group could be the
> > > > group to add, probably.
> > > > 
> > > > Another point I wonder is other kernel test suite than blktests.
> > > > Don't we have more appropriate test suite to check PCI device
> > > > rescan/remove race ? Such a test sounds more like a PCI bus
> > > > sub-system test than block/storage test.
> > > 
> > > I'm not aware of such a test, but it would be nice to have one.
> > > 
> > > Can you share your qemu config so I can reproduce this locally?
> > > 
> > > Thanks for finding and reporting this!
> > 
> > This ought to be reproducible with any pci device that can be
> > removed. Since we initially observed with nvme, you can try with
> > such a device. A quick way to get one appearing in qemu is to add
> > parameters:
> > 
> >         -drive id=n,if=none,file=null-co://,format=raw \
> > 	-device nvme,serial=foobar,drive=n
> 
> Did you have chance to reproduce the WARN? Recently, it was reported
> again [1] and getting attention.

I have not paid any attention to this yet.  From what I can tell, the
problem was discovered by a test case (i.e., not reported by a
real-world user), it is not a recent regression, we haven't identified
a commit that introduced the problem, and we do not have a potential
fix for it.  Obviously it needs to be fixed and I'm not trying to
minimize the problem; I just want to calibrate it against everything
else.

> [1] https://lore.kernel.org/linux-block/4ed3028b-2d2f-8755-fec2-0b9cb5ad42d2@fujitsu.com/
> 
> -- 
> Shin'ichiro Kawasaki