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

Link Lin <[email protected]> Fri, 31 Jul 2026 13:21:40 -0700
Newsgroups dev.linux.lists.virtualization,org.kernel.vger.linux-kernel,org.kernel.vger.stable,org.kvack.linux-mm
Message-ID <CALUx4KRoCco0HA=Y_qFzSD=CegbJPUkQkvjRb1Y3UcgRdwQToA@mail.gmail.com>
On Thu, Jul 23, 2026 at 2:15=E2=80=AFAM Michael S. Tsirkin <[email protected]>=
 wrote:
>
> I suspect rest of work items we have, e.g. update_balloon_stats_work/upda=
te_balloon_size_work
> all have issues around freeze/restore and error handling.
>
> --
> MST
>

Hi Michael,

We have indeed discovered a kernel crash in update_balloon_stats_work
after the balloon driver failed to resume and initialize in our
production fleet.

Alex Wilkins <[email protected]> diagnosed, root caused, and
reported this vulnerability. I am currently drafting and testing a
2-patch series to gracefully unregister callbacks and cancel work
items on resume failure so that the VM continues running without the
balloon driver instead of crashing with a kernel panic.

I wanted to follow up and let you know that we are actively working on
this. I will send out the patches to the list as soon as they are
sufficiently tested.

Best,
Link