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

["Mantas Mikulėnas" <grawity@gmail.com>]

On 2025-02-07 13:16, Bernd Schubert wrote:
> 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@suse.cz> 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.

I used the "Obfuscate" app:
https://flathub.org/apps/com.belmoussaoui.Obfuscate

Selecting a JPEG/PNG file in GNOME's file browser (Nautilus) and 
choosing "Open with > Obfuscate" reliably triggers the bug. (Running 
`com.belmoussaoui.Obfuscate` and opening a file from within the app 
likely would, too, but at the time I didn't try that.)