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

[Mantas Mikulėnas]

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@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.

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.)