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 <20201001195525.3477-2-dirk@gouders.net> <ghh7rdy9hg.fsf@gouders.net>
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From:   Alex Deucher <alexdeucher@gmail.com>
Date:   Thu, 1 Oct 2020 16:47:55 -0400
Message-ID: <CADnq5_OUYWCceZm=sNpFZ7cquyxmz5GO5JPznyFhZDSu+pjj=Q@mail.gmail.com>
Subject: Re: [PATCH 1/1] drm/amdgpu: fix NULL pointer dereference for Renoir
To:     Dirk Gouders <dirk@gouders.net>
Cc:     Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        LKML <linux-kernel@vger.kernel.org>,
        amd-gfx list <amd-gfx@lists.freedesktop.org>,
        Hawking Zhang <Hawking.Zhang@amd.com>,
        Evan Quan <evan.quan@amd.com>
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On Thu, Oct 1, 2020 at 4:33 PM Dirk Gouders <dirk@gouders.net> wrote:
>
> Dirk Gouders <dirk@gouders.net> writes:
>
> > Commit c1cf79ca5ced46 (drm/amdgpu: use IP discovery table for renoir)
> > introduced a NULL pointer dereference when booting with
> > amdgpu.discovery=0, because it removed the call of vega10_reg_base_init()
> > for that case.
> >
> > Fix this by calling that funcion if amdgpu_discovery == 0 in addition to
> > the case that amdgpu_discovery_reg_base_init() failed.
> >
> > Fixes: c1cf79ca5ced46 (drm/amdgpu: use IP discovery table for renoir)
> > Signed-off-by: Dirk Gouders <dirk@gouders.net>
> > Cc: Hawking Zhang <Hawking.Zhang@amd.com>
> > Cc: Evan Quan <evan.quan@amd.com>
> > ---
> >  drivers/gpu/drm/amd/amdgpu/soc15.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/soc15.c b/drivers/gpu/drm/amd/amdgpu/soc15.c
> > index 84d811b6e48b..f8cb62b326d6 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/soc15.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/soc15.c
> > @@ -694,12 +694,12 @@ static void soc15_reg_base_init(struct amdgpu_device *adev)
> >                * it doesn't support SRIOV. */
> >               if (amdgpu_discovery) {
> >                       r = amdgpu_discovery_reg_base_init(adev);
> > -                     if (r) {
> > -                             DRM_WARN("failed to init reg base from ip discovery table, "
> > -                                      "fallback to legacy init method\n");
> > -                             vega10_reg_base_init(adev);
> > -                     }
> > +                     if (r == 0)
> > +                       break;
>
> Grrr, wrong indentation here.
> But I will wait for your review before v1.

Fixed up locally and applied.  Thanks!

Alex


>
> Dirk
>
>
> > +                     DRM_WARN("failed to init reg base from ip discovery table, "
> > +                              "fallback to legacy init method\n");
> >               }
> > +             vega10_reg_base_init(adev);
> >               break;
> >       case CHIP_VEGA20:
> >               vega20_reg_base_init(adev);