Re: [syzbot] [mm?] kernel BUG in collapse_scan_file

David Hildenbrand (Arm)
2026-03-19T11:00:03Z

> We shouldn't, really, be just ignoring splatting kernels like that. At least
> that's my personal point of view on it.

Yes, we shouldn't.

>
> But anyway I really don't have the time or energy to try to track this down or
> push on this further.

The problem I'm having is that reverting the commit might hide a real
problem, and understanding weather there is a real problem requires ...
real work.

Willy said

"It *might* still be safe in this instance; I'll look
at this carefully for a bit and decide how best to fix it."

That likely didn't happen.

Later he said:

"But this is a long and complicated function (over 400 lines!) and I
don't know if fixing this one way or the other would serve to make other
bugs more likely or expose some future problem to the debugging code."

with

"This isn't the kind of thing where you can just jump in with a one line
patch and actually be helpful, sorry."

So I am clueless if there is a real problem there or whether it's just a
false positive. And whether (if it's a real problem) the simple fix
would actually be a good temporary fix ("make other bugs more likely").

I can try finding some time to look into that, but pagecache code is not
particularly the code I'm familiar with ...

--
Cheers,

David