Re: [PATCH] gfs2: keep per-bio end_io when splitting journal head reads

[Andreas Gruenbacher]

On Fri, Apr 24, 2026 at 10:52 PM Wxm-233 <2200013188@xxxxxxxxxxxxxx> wrote:
> Hi Andreas,
>
> Thanks for pointing me to commit 469d71512d13 ("Revert "gfs2: Fix use
> of bio_chain"").
>
> I had missed that revert. After looking at it again, I agree that my
> patch direction was wrong, so I will drop that patch.
>
> What I can say about the trigger so far is:
>
> - we reproduced this on 6.18.5

Okay, commit 469d71512d13 ("Revert "gfs2: Fix use of bio_chain"") was
added to v6.18.7, so no surprise there.

> - the report came from a syzkaller-style fuzzing run
> - the crash happens during GFS2 journal recovery, not on a normal data
>   path
> - the stack is:
>
>     gfs2_recover_func()
>       -> gfs2_find_jhead()
>       -> gfs2_chain_bio()
>       -> bio_chain()
>
> From the code path, it appears to happen during journal head lookup
> when the read enters the split-bio case in gfs2_find_jhead().

Thanks,
Andreas