Re: kernel panic: stack is corrupted in udp4_lib_lookup2

[Eric Dumazet]

On 01/03/2019 05:07 AM, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:ÂÂÂ 195303136f19 Merge tag 'kconfig-v4.21-2' of git://git.kern..
> git tree:ÂÂÂÂÂÂ upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12245d8f400000
> kernel config:Â https://syzkaller.appspot.com/x/.config?x=5e7dc790609552d7
> dashboard link: https://syzkaller.appspot.com/bug?extid=4ad25edc7a33e4ab91e0
> compiler:ÂÂÂÂÂÂ gcc (GCC) 8.0.1 20180413 (experimental)
> 
> Unfortunately, I don't have any reproducer for this crash yet.
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+4ad25edc7a33e4ab91e0@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> protocol 88fb is buggy, dev hsr_slave_1
> protocol 88fb is buggy, dev hsr_slave_0
> protocol 88fb is buggy, dev hsr_slave_1
> FAT-fs (loop0): invalid media value (0x00)
> FAT-fs (loop0): Can't find a valid FAT filesystem
> Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: udp4_lib_lookup2+0x7ea/0x7f0 net/ipv4/udp.c:455
> CPU: 1 PID: 17960 Comm: syz-executor2 Not tainted 4.20.0+ #176
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
> 
> 
> ---
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> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx
> 
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Maybe commit 11789039da536fea96c98a40c2b441decf2e7323
Author: Stefano Brivio <sbrivio@xxxxxxxxxx>
Date:   Tue Dec 18 00:13:17 2018 +0100

    fou: Prevent unbounded recursion in GUE error handler

Forgot to deal with IPv6 ?