Re: [WARNING: UNSCANNABLE EXTRACTION FAILED]Re: [bug report] fstests generic/774 hang

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Nov 10, 2025 at 12:46:19PM +0000, Shinichiro Kawasaki wrote:
> On Nov 09, 2025 / 17:32, Ojaswin Mujoo wrote:
> > On Thu, Nov 06, 2025 at 08:19:12AM +0000, Shinichiro Kawasaki wrote:
> [...]
> > > I tried the other "atomicwrites" test. I found g778 took very long time.
> > > I think it implies that g778 may have similar problem as g774.
> > > 
> > >   g765: [not run] write atomic not supported by this block device
> > >   g767: 11s
> > >   g768: 13s
> > >   g769: 13s
> > >   g770: 35s
> > >   g773: [not run] write atomic not supported by this block device
> > >   g774: did not completed after 3 hours run (and kernel reported the INFO messages)
> > >   g775: 48s
> > >   g776: [not run] write atomic not supported by this block device
> > >   g778: did not completed after 50 minutes run
> > 
> > Hi Shinichiro
> > 
> > Hmm that's strange, g/778 should tune itself to the speed of the device
> > ideally. Will you be able to share the results/generic/778.full file.
> > That might give some hints.
> 
> Please find the attached 778.full.gz, which I copied about 50 minutes after
> the test case start. The test case was still running at that time. Near the end
> of the full file, I find "Iteration 13". It looks like the test case is not
> hanging, but just taking long time to complete the 20 iterations.

<nod> 778 invokes xfs_io and fallocate a few tens of thousands of times,
which makes the test runtime really slow if fork/exec() aren't fast.  I
try to fix that here:

https://lore.kernel.org/fstests/176279908967.605950.2192923313361120314.stgit@frogsfrogsfrogs/T/#t

As well as reducing the test file size for 774, per everyone's comments.

--D