Re: REGRESSION: lockdep warning triggered by 15b9ce7ecd: virtio_balloon: stay awake while adjusting balloon

[Theodore Ts'o]

On Wed, Jan 10, 2024 at 03:11:01AM -0500, Michael S. Tsirkin wrote:
> On Mon, Jan 08, 2024 at 04:50:15PM -0500, Theodore Ts'o wrote:
> > Hi, while doing final testing before sending a pull request, I merged
> > in linux-next, and commit 5b9ce7ecd7: virtio_balloon: stay awake while
> > adjusting balloon seems to be causing a lockdep warning (see attached)
> > when running gce-xfstests on a Google Compute Engine e2 VM.  I was not
> > able to trigger it using kvm-xfstests, but the following command:
> > "gce-xfstests -C 10 ext4/4k generic/476) was sufficient to triger the
> > problem.   For more information please see [1] and [2].
> > 
> > [1] https://github.com/tytso/xfstests-bld/blob/master/Documentation/gce-xfstests.md
> > [2] https://thunk.org/gce-xfstests
> > 
> > I found it by looking at the git logs, and this commit aroused my
> > suspicions, and I further testing showed that the lockdep warning was
> > reproducible with this commit, but not when testing with the
> > immediately preceeding commit (15b9ce7ecd^).
> > 
> > Cheers,
> 
> 
> Thanks a lot for the report!
> I pushed a fixed patch out (tree rebased).
> Would be great if you can confirm it's allright now.

I manually fixed up the white-space issues with the patch last night,
and verified that it fixed it for me with an overnight test run.  (My
patch was versus next-20240109, and then I tested with ext4/dev merged
in.  Previously I had noted the problem with next-20240107 with
ext4/dev merged in.)

Thanks,

					- Ted