Re: kernel BUG at arch/x86/mm/physaddr.c:LINE! (2)

From: Alexander Potapenko
Date: Thu Apr 04 2019 - 10:47:16 EST


On Wed, Mar 20, 2019 at 9:35 PM syzbot
<syzbot+6c0effb5877f6b0344e2@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> syzbot has bisected this bug to:
>
> commit 6d469a202ee73196d0df76025af80bd6a379e658
> Author: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
> 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=12639fd7200000
> start commit: 6d469a20 Merge tag 'v4.12-rc1' into patchwork
> git tree: upstream
> final crash: https://syzkaller.appspot.com/x/report.txt?x=15639fd7200000
> console output: https://syzkaller.appspot.com/x/log.txt?x=11639fd7200000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d86f24333880b605
> dashboard link: https://syzkaller.appspot.com/bug?extid=6c0effb5877f6b0344e2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1312062b400000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=131bd093400000
>
> Reported-by: syzbot+6c0effb5877f6b0344e2@xxxxxxxxxxxxxxxxxxxxxxxxx
> 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().

--
Alexander Potapenko
Software Engineer

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