Re: [REGRESSION][BISECTED] Crash with Bad page state for FUSE/Flatpak related applications since v6.13

From: Bernd Schubert
Date: Fri Feb 07 2025 - 06:16:27 EST




On 2/7/25 11:55, Vlastimil Babka wrote:
> On 2/7/25 11:43, Miklos Szeredi wrote:
>> On Fri, 7 Feb 2025 at 11:25, Vlastimil Babka <vbabka@xxxxxxx> wrote:
>>
>>> Could be a use-after free of the page, which sets PG_lru again. The list
>>> corruptions in __rmqueue_pcplist also suggest some page manipulation after
>>> free. The -1 refcount suggests somebody was using the page while it was
>>> freed due to refcount dropping to 0 and then did a put_page()?
>>
>> Can you suggest any debug options that could help pinpoint the offender?
>
> CONFIG_DEBUG_VM enables a check in put_page_testzero() that would catch the
> underflow (modulo a tiny race window where it wouldn't). Worth trying.

I typically run all of my tests with these options enabled

https://github.com/bsbernd/tiny-qemu-virtio-kernel-config


If Christian or Mantas could tell me what I need to install and run, I
could probably quickly give it a try.



Thanks,
Bernd