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From:   Alexander Potapenko <glider@google.com>
Date:   Thu, 4 Apr 2019 16:47:00 +0200
Message-ID: <CAG_fn=VnXmDSc_QNqyEv7f7iwHXC6taBq1t55fHWZpLZ0EdiNw@mail.gmail.com>
Subject: Re: kernel BUG at arch/x86/mm/physaddr.c:LINE! (2)
To:     syzbot <syzbot+6c0effb5877f6b0344e2@syzkaller.appspotmail.com>
Cc:     David Miller <davem@davemloft.net>, hverkuil@xs4all.nl,
        linux-can@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        linux-media@vger.kernel.org, mchehab@kernel.org,
        mchehab@s-opensource.com, mkl@pengutronix.de,
        Networking <netdev@vger.kernel.org>, socketcan@hartkopp.net,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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On Wed, Mar 20, 2019 at 9:35 PM syzbot
<syzbot+6c0effb5877f6b0344e2@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this bug to:
>
> commit 6d469a202ee73196d0df76025af80bd6a379e658
> Author: Mauro Carvalho Chehab <mchehab@s-opensource.com>
> Date:   Sun May 14 17:07:21 2017 +0000
>
>      Merge tag 'v4.12-rc1' into patchwork
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=3D12639fd720=
0000
> start commit:   6d469a20 Merge tag 'v4.12-rc1' into patchwork
> git tree:       upstream
> final crash:    https://syzkaller.appspot.com/x/report.txt?x=3D15639fd720=
0000
> console output: https://syzkaller.appspot.com/x/log.txt?x=3D11639fd720000=
0
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3Dd86f24333880b=
605
> dashboard link: https://syzkaller.appspot.com/bug?extid=3D6c0effb5877f6b0=
344e2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D1312062b400=
000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D131bd09340000=
0
>
> Reported-by: syzbot+6c0effb5877f6b0344e2@syzkaller.appspotmail.com
> Fixes: 6d469a20 ("Merge tag 'v4.12-rc1' into patchwork")
>
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I believe this bug is caused by vivid_vid_cap_s_selection() calling
kfree(dev->bitmap_cap).
This makes little sense, as dev->bitmap_cap seems to be allocated
using vzalloc().

--=20
Alexander Potapenko
Software Engineer

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