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From:   Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu, 5 Dec 2019 15:04:55 +0100
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Subject: Re: INFO: task hung in fb_open
To:     syzbot <syzbot+a4ae1442ccc637162dc1@syzkaller.appspotmail.com>
Cc:     Dave Airlie <airlied@linux.ie>,
        Ayan Kumar Halder <ayan.halder@arm.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Peter Rosin <peda@axentia.se>, Sam Ravnborg <sam@ravnborg.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        "Syrjala, Ville" <ville.syrjala@linux.intel.com>,
        Chen-Yu Tsai <wens@csie.org>
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On Thu, Dec 5, 2019 at 2:38 PM syzbot
<syzbot+a4ae1442ccc637162dc1@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this bug to:
>
> commit 979c11ef39cee79d6f556091a357890962be2580
> Author: Ayan Kumar Halder <ayan.halder@arm.com>
> Date:   Tue Jul 17 17:13:46 2018 +0000
>
>      drm/sun4i: Substitute sun4i_backend_format_is_yuv() with format->is_yuv

Pretty sure your GCD machine is not using the sun4i driver. It's also
very far away from the code that's blowing up. bisect gone wrong?
-Daniel

>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15d2f97ee00000
> start commit:   596cf45c Merge branch 'akpm' (patches from Andrew)
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=13d2f97ee00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=7d8ab2e0e09c2a82
> dashboard link: https://syzkaller.appspot.com/bug?extid=a4ae1442ccc637162dc1
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14273edae00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15e7677ae00000
>
> Reported-by: syzbot+a4ae1442ccc637162dc1@syzkaller.appspotmail.com
> Fixes: 979c11ef39ce ("drm/sun4i: Substitute sun4i_backend_format_is_yuv()
> with format->is_yuv")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection


-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch