Re: [PATCH 3.16 43/72] thermal: Fix use-after-free when unregistering thermal zone device

Zhang Rui
2019-12-09T01:40:45Z

On Sun, 2019-12-08 at 18:09 +0000, Ben Hutchings wrote:
> On Sun, 2019-12-08 at 16:22 +0000, Ido Schimmel wrote:
> > On Sun, Dec 08, 2019 at 01:53:27PM +0000, Ben Hutchings wrote:
> > > 3.16.79-rc1 review patch. If anyone has any objections, please
> > > let me know.
> > >
> > > ------------------
> > >
> > > From: Ido Schimmel <idosch@mellanox.com>
> > >
> > > commit 1851799e1d2978f68eea5d9dff322e121dcf59c1 upstream.
> > >
> > > thermal_zone_device_unregister() cancels the delayed work that
> > > polls the
> > > thermal zone, but it does not wait for it to finish. This is racy
> > > with
> > > respect to the freeing of the thermal zone device, which can
> > > result in a
> > > use-after-free [1].
> > >
> > > Fix this by waiting for the delayed work to finish before freeing
> > > the
> > > thermal zone device. Note that thermal_zone_device_set_polling()
> > > is
> > > never invoked from an atomic context, so it is safe to call
> > > cancel_delayed_work_sync() that can block.
> >
> > Ben,
> >
> > Wei Wang (copied) found a problem with this patch and fixed it:
> >
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=163b00cde7cf2206e248789d2780121ad5e6a70b
> >
> > I believe you should take both patches to your tree.
>
> Thanks, I will add that now that it is in Linus's tree.
>

yes, please do, thanks!

-rui
> Ben.
>