Re: [PATCH v3] mm/page_reporting: use system_freezable_wq to fix UAF during suspend

Andrew Morton <[email protected]> Wed, 22 Jul 2026 17:36:39 -0700
Newsgroups dev.linux.lists.virtualization,org.kernel.vger.linux-kernel,org.kernel.vger.stable,org.kvack.linux-mm
Message-ID <[email protected]>
On Tue, 21 Jul 2026 00:55:33 +0000 Link Lin <[email protected]> wrote:

> During PM freeze (e.g. S3 suspend or S4 hibernation), device drivers like
> virtio_balloon reset their underlying virtio devices and delete their
> virtqueues via vdev->config->del_vqs().
> 
> ...
> 
> Fix this by switching page reporting work to system_freezable_wq.
>
> ...
>

Thanks.

> Fixes: 924a663f75e2 ("virtio-balloon: Reporting free page reservations")

hm, now where did that come from.  I can find no such commit and that's
the second time this very unusual thing has happened in 30 minutes!  I
wonder what's going on.

I'll use

	36e66c554b5c ("mm: introduce Reported pages")

OK?

> Cc: [email protected]

The bug is very old so I won't fast-track this fix into 7.2-rcX.

AI review pointed at a possible pre-existing use-after-free issue,
related to virtio-balloon.  But I think this is a rephrasing of the
issue it flagged against your v2 patch.

	https://sashiko.dev/#/patchset/[email protected]