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From:   Doug Anderson <dianders@chromium.org>
Date:   Mon, 4 Oct 2021 17:40:49 -0700
Message-ID: <CAD=FV=V8MoYX2deqD_YE6ii9+VFbwqX0bre=5xaYe8ZwwExziQ@mail.gmail.com>
Subject: Re: [PATCH] drm/edid: Fix crash with zero/invalid EDID
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     DRI Development <dri-devel@lists.freedesktop.org>,
        kernel test robot <oliver.sang@intel.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        Jani Nikula <jani.nikula@intel.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Sam Ravnborg <sam@ravnborg.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>
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Hi,

On Mon, Oct 4, 2021 at 10:14 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Douglas,
>
> On Mon, Oct 4, 2021 at 6:22 PM Douglas Anderson <dianders@chromium.org> wrote:
> > In the commit bac9c2948224 ("drm/edid: Break out reading block 0 of
> > the EDID") I broke out reading the base block of the EDID to its own
> > function. Unfortunately, when I did that I messed up the handling when
> > drm_edid_is_zero() indicated that we had an EDID that was all 0x00 or
> > when we went through 4 loops and didn't get a valid EDID. Specifically
> > I needed to pass the broken EDID to connector_bad_edid() but now I was
> > passing an error-pointer.
> >
> > Let's re-jigger things so we can pass the bad EDID in properly.
> >
> > Fixes: bac9c2948224 ("drm/edid: Break out reading block 0 of the EDID")
> > Reported-by: kernel test robot <oliver.sang@intel.com>
> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
>
> The crash is was seeing is gone, so
> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Thanks for testing! I'll plan to apply tomorrow morning (California
time) to balance between giving folks a chance to yell at me for my
patch and the urgency of fixing the breakage.

-Doug