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

[Vlastimil Babka]

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.

> Thanks,
> Miklos