Re: WARNING: bad usercopy in corrupted (2)

From: Dmitry Vyukov
Date: Wed Mar 20 2019 - 05:40:17 EST


On Wed, Mar 20, 2019 at 1:49 AM syzbot
<syzbot+d89b30c46434c433dbf8@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> syzbot has bisected this bug to:
>
> commit b8a51b38e4d4dec3e379d52c0fe1a66827f7cf1e
> Author: Stefano Brivio <sbrivio@xxxxxxxxxx>
> Date: Thu Nov 8 11:19:23 2018 +0000
>
> fou, fou6: ICMP error handlers for FoU and GUE
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14a57f83200000
> start commit: b8a51b38 fou, fou6: ICMP error handlers for FoU and GUE
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=12a57f83200000
> kernel config: https://syzkaller.appspot.com/x/.config?x=c36a72af2123e78a
> dashboard link: https://syzkaller.appspot.com/bug?extid=d89b30c46434c433dbf8
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=170f6a47400000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12e1df7b400000
>
> Reported-by: syzbot+d89b30c46434c433dbf8@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: b8a51b38 ("fou, fou6: ICMP error handlers for FoU and GUE")

That commit caused lots of crashes that look completely differently.
Now all that is fixed. The last crash for this bugs happened 2+ months
ago. So let's just do:

#syz fix: fou: Prevent unbounded recursion in GUE error handler also
with UDP-Lite