Re: WARNING in xt_compat_add_offset

[syzbot]

syzbot has bisected this bug to:

commit 2035f3ff8eaa29cfb5c8e2160b0f6e85eeb21a95
Author: Florian Westphal <fw@xxxxxxxxx>
Date:   Mon Jan 21 20:54:36 2019 +0000

    netfilter: ebtables: compat: un-break 32bit setsockopt when no rules  
are present

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1462834d200000
start commit:   8a61716f Merge tag 'ceph-for-5.0-rc8' of git://github.com/..
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=1662834d200000
console output: https://syzkaller.appspot.com/x/log.txt?x=1262834d200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7132344728e7ec3f
dashboard link: https://syzkaller.appspot.com/bug?extid=276ddebab3382bbf72db
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=140c0914c00000

Reported-by: syzbot+276ddebab3382bbf72db@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 2035f3ff8eaa ("netfilter: ebtables: compat: un-break 32bit  
setsockopt when no rules are present")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection