[PATCH] drm/mst: Fix NULL pointer dereference at drm_dp_add_payload_part2

[Alex Deucher]

Applied and pushed out:
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=8a0a7b98d4b6eeeab337ec25daa4bc0a5e710a15

Alex

On Tue, May 21, 2024 at 12:12 PM Alex Deucher <alexdeucher at gmail.com> wrote:
>
> I've got it teed up.  Is drm-misc-fixes the right branch since we are
> in the merge window?
>
> Alex
>
> On Tue, May 21, 2024 at 7:20 AM Linux regression tracking (Thorsten
> Leemhuis) <regressions at leemhuis.info> wrote:
> >
> > Hi, Thorsten here, the Linux kernel's regression tracker. Top-posting
> > for once, to make this easily accessible to everyone.
> >
> > Hmm, from here it looks like the patch now that it was reviewed more
> > that a week ago is still not even in -next. Is there a reason?
> >
> > I know, we are in the merge window. But at the same time this is a fix
> > (that already lingered on the lists for way too long before it was
> > reviewed) for a regression in a somewhat recent kernel, so it in Linus
> > own words should be "expedited"[1].
> >
> > Or are we again just missing a right person for the job in the CC?
> > Adding Dave and Sima just in case.
> >
> > Ciao, Thorsten
> >
> > [1]
> > https://lore.kernel.org/all/CAHk-=wis_qQy4oDNynNKi5b7Qhosmxtoj1jxo5wmB6SRUwQUBQ@mail.gmail.com/
> >
> > On 12.05.24 18:11, Limonciello, Mario wrote:
> > > On 5/10/2024 4:24 AM, Jani Nikula wrote:
> > >> On Fri, 10 May 2024, "Lin, Wayne" <Wayne.Lin at amd.com> wrote:
> > >>>> -----Original Message-----
> > >>>> From: Limonciello, Mario <Mario.Limonciello at amd.com>
> > >>>> Sent: Friday, May 10, 2024 3:18 AM
> > >>>> To: Linux regressions mailing list <regressions at lists.linux.dev>;
> > >>>> Wentland, Harry
> > >>>> <Harry.Wentland at amd.com>; Lin, Wayne <Wayne.Lin at amd.com>
> > >>>> Cc: lyude at redhat.com; imre.deak at intel.com; Leon Weiß
> > >>>> <leon.weiss at ruhr-uni-
> > >>>> bochum.de>; stable at vger.kernel.org; dri-devel at lists.freedesktop.org;
> > >>>> amd-
> > >>>> gfx at lists.freedesktop.org; intel-gfx at lists.freedesktop.org
> > >>>> Subject: Re: [PATCH] drm/mst: Fix NULL pointer dereference at
> > >>>> drm_dp_add_payload_part2
> > >>>>
> > >>>> On 5/9/2024 07:43, Linux regression tracking (Thorsten Leemhuis) wrote:
> > >>>>> On 18.04.24 21:43, Harry Wentland wrote:
> > >>>>>> On 2024-03-07 01:29, Wayne Lin wrote:
> > >>>>>>> [Why]
> > >>>>>>> Commit:
> > >>>>>>> - commit 5aa1dfcdf0a4 ("drm/mst: Refactor the flow for payload
> > >>>>>>> allocation/removement") accidently overwrite the commit
> > >>>>>>> - commit 54d217406afe ("drm: use mgr->dev in drm_dbg_kms in
> > >>>>>>> drm_dp_add_payload_part2") which cause regression.
> > >>>>>>>
> > >>>>>>> [How]
> > >>>>>>> Recover the original NULL fix and remove the unnecessary input
> > >>>>>>> parameter 'state' for drm_dp_add_payload_part2().
> > >>>>>>>
> > >>>>>>> Fixes: 5aa1dfcdf0a4 ("drm/mst: Refactor the flow for payload
> > >>>>>>> allocation/removement")
> > >>>>>>> Reported-by: Leon Weiß <leon.weiss at ruhr-uni-bochum.de>
> > >>>>>>> Link:
> > >>>>>>> https://lore.kernel.org/r/38c253ea42072cc825dc969ac4e6b9b600371cc8.c
> > >>>>>>> amel at ruhr-uni-bochum.de/
> > >>>>>>> Cc: lyude at redhat.com
> > >>>>>>> Cc: imre.deak at intel.com
> > >>>>>>> Cc: stable at vger.kernel.org
> > >>>>>>> Cc: regressions at lists.linux.dev
> > >>>>>>> Signed-off-by: Wayne Lin <Wayne.Lin at amd.com>
> > >>>>>>
> > >>>>>> I haven't been deep in MST code in a while but this all looks pretty
> > >>>>>> straightforward and good.
> > >>>>>>
> > >>>>>> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
> > >>>>>
> > >>>>> Hmmm, that was three weeks ago, but it seems since then nothing
> > >>>>> happened to fix the linked regression through this or some other
> > >>>>> patch. Is there a reason? The build failure report from the CI maybe?
> > >>>>
> > >>>> It touches files outside of amd but only has an ack from AMD.  I
> > >>>> think we
> > >>>> /probably/ want an ack from i915 and nouveau to take it through.
> > >>>
> > >>> Thanks, Mario!
> > >>>
> > >>> Hi Thorsten,
> > >>> Yeah, like what Mario said. Would also like to have ack from i915 and
> > >>> nouveau.
> > >>
> > >> It usually works better if you Cc the folks you want an ack from! ;)
> > >>
> > >> Acked-by: Jani Nikula <jani.nikula at intel.com>
> > >>
> > >
> > > Thanks! Can someone with commit permissions take this to drm-misc?
> > >
> > >
> > >