Re: [PATCH v8] ext4: fix slab-use-after-free in do_split()

[Shuai Liu]

Hi Honza,

Thank you for the detailed review and the honest feedback.

You are right - I was iterating against the AI review bot's findings
without pausing to seek human feedback, and that was the wrong
prioritization. I also agree with your point on maintainability: disk
metadata can be corrupted in unbounded ways, ext4 has always treated
graceful handling as best effort, and adding per-alias checks at every
call site is expensive protection for a niche case.

Given that, how would you like to proceed? The syzbot crash itself is
real (KASAN slab-use-after-free from aliased buffer heads), so I could
downscale this to a minimal fix for the actual reported crash (just the
do_split() *bh/bh2 alias check) if you think that single check is
worthwhile. Alternatively I can drop the series entirely, and I would
be interested in helping explore the buffer_head metadata tag approach
you outlined, if that is something you would welcome.

Thanks again,
Shuai Liu