Re: kernel BUG at mm/slab.c:LINE! (3)

From: Dmitry Vyukov
Date: Thu Mar 21 2019 - 02:01:42 EST


On Wed, Mar 20, 2019 at 9:55 PM syzbot
<syzbot+2182db487a523d86bf34@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=161b63cf200000
> start commit: b8a51b38 fou, fou6: ICMP error handlers for FoU and GUE
> git tree: net-next
> final crash: https://syzkaller.appspot.com/x/report.txt?x=151b63cf200000
> console output: https://syzkaller.appspot.com/x/log.txt?x=111b63cf200000
> kernel config: https://syzkaller.appspot.com/x/.config?x=4a0a89f12ca9b0f5
> dashboard link: https://syzkaller.appspot.com/bug?extid=2182db487a523d86bf34
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=148d46d5400000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c6a225400000
>
> Reported-by: syzbot+2182db487a523d86bf34@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