Coverity: nouveau_dp_irq(): Null pointer dereferences

[Karol Herbst]

On Fri, Nov 11, 2022 at 9:16 PM Kees Cook <keescook at chromium.org> wrote:
>
> On Fri, Nov 11, 2022 at 09:06:54PM +0100, Karol Herbst wrote:
> > On Fri, Nov 11, 2022 at 8:21 PM Kees Cook <keescook at chromium.org> wrote:
> > >
> > > On Fri, Nov 11, 2022 at 11:13:17AM +0200, Jani Nikula wrote:
> > > > On Thu, 10 Nov 2022, coverity-bot <keescook at chromium.org> wrote:
> > > > > Hello!
> > > > >
> > > > > This is an experimental semi-automated report about issues detected by
> > > > > Coverity from a scan of next-20221110 as part of the linux-next scan project:
> > > > > https://scan.coverity.com/projects/linux-next-weekly-scan
> > > > >
> > > > > You're getting this email because you were associated with the identified
> > > > > lines of code (noted below) that were touched by commits:
> > > > >
> > > > >   Mon Aug 31 19:10:08 2020 -0400
> > > > >     a0922278f83e ("drm/nouveau/kms/nv50-: Refactor and cleanup DP HPD handling")
> > > >
> > > > Hi Kees, this looks like a good idea, but maybe double check the Cc list
> > > > generation? I was Cc'd on four mails today that I thought were
> > > > irrelevant to me.
> > >
> > > Hi!
> > >
> > > Heh, I was recently asked to _expand_ the CC list. :)
> > >
> > > For these last pass of reports, I added a get_maintainers.pl run to the
> > > identified commit. In this instance, the commit touched:
> > >
> > >  drivers/gpu/drm/nouveau/dispnv04/disp.c     |    6 +
> > >  drivers/gpu/drm/nouveau/dispnv50/disp.c     |  192 ++++++++++++++++++++++--------------------------
> > >  drivers/gpu/drm/nouveau/nouveau_connector.c |   14 ---
> > >  drivers/gpu/drm/nouveau/nouveau_display.c   |    2
> > >  drivers/gpu/drm/nouveau/nouveau_display.h   |    2
> > >  drivers/gpu/drm/nouveau/nouveau_dp.c        |  132 ++++++++++++++++++++++++++++-----
> > >  drivers/gpu/drm/nouveau/nouveau_encoder.h   |   33 +++++++-
> > >  7 files changed, 244 insertions(+), 137 deletions(-)
> > >
> > > And the get_maintainers.pl rationale was:
> > >
> > > Ben Skeggs <bskeggs at redhat.com> (supporter:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS,commit_signer:1/1=100%,commit_signer:6/16=38%,authored:4/16=25%,added_lines:23/124=19%,removed_lines:36/152=24%)
> > > Karol Herbst <kherbst at redhat.com> (supporter:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS,commit_signer:2/1=100%)
> > > Lyude Paul <lyude at redhat.com> (supporter:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS,commit_signer:9/16=56%,authored:6/16=38%,added_lines:92/124=74%,removed_lines:107/152=70%)
> > > David Airlie <airlied at gmail.com> (maintainer:DRM DRIVERS)
> > > Daniel Vetter <daniel at ffwll.ch> (maintainer:DRM DRIVERS)
> > > Ilia Mirkin <imirkin at alum.mit.edu> (commit_signer:1/1=100%,authored:1/1=100%,added_lines:2/2=100%,removed_lines:2/2=100%)
> > > "Nathan E. Egge" <unlord at xiph.org> (commit_signer:1/1=100%)
> > > Jani Nikula <jani.nikula at intel.com> (commit_signer:6/16=38%)
> > > Dave Airlie <airlied at redhat.com> (commit_signer:5/16=31%)
> > > Thomas Zimmermann <tzimmermann at suse.de> (commit_signer:4/16=25%,authored:4/16=25%)
> > > dri-devel at lists.freedesktop.org (open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS)
> > > nouveau at lists.freedesktop.org (open list:DRM DRIVER FOR NVIDIA GEFORCE/QUADRO GPUS)
> > >
> >
> > I'd say it's good enough to message supporters and the mailing lists
> > for at least Nouveau code, maybe even all drm drivers.
>
> i.e. leave out the commit_signer hits?
>

yes.

> > Not sure what to do about actual maintainers, but I doubt Dave and
> > Daniel want to be CCed on every Coverity report here either.
>
> I updated the CC logic based on this feedback:
> https://lore.kernel.org/linux-hardening/87h6zgfub4.fsf@kernel.org/
>
> So maybe just mailing lists?
>

That should be good enough, but maybe the DRM subsystem is big enough
so it's reasonable to add special rules. For Nouveau either way is
fine.

> --
> Kees Cook
>