> > > > Curiously, I couldn't find any relevant crashes on the KMSAN syzbot
> > > > instance, but the issue is legit.
> > > > Thank you so much for fixing this!
> > > >
> > > > Any chance you can add a test case for it to mm/kmsan/kmsan_test.c?
> > >
> > > Unfortunately most of the KMSAN test cases already fail on upstream,
> > > which makes it difficult to develop new ones:
> >
> > The KMSAN test failures bisect to the following commit:
> >
> >     commit f90b474a35744b5d43009e4fab232e74a3024cae
> >     Author: Vlastimil Babka <vbabka@suse.cz>
> >     Date:   Mon Mar 10 13:40:17 2025 +0100
> >
> >         mm: Fix the flipped condition in gfpflags_allow_spinning()
> >
> > I'm not sure why.  Apparently something related to lib/stackdepot.c.
> >
> > Reverting that commit on top of upstream fixes the KMSAN tests.
> >
>
> Rolling back all the BPF (?) related changes that were made to
> lib/stackdepot.c in v6.15 fixes this too.  Looks like there was a
> regression where stack traces stopped being saved in some cases.

Hmm, the tests don't fail for me on v6.17-rc5 with the attached config.
Could you share yours?