syzbot has bisected this bug to:

commit 98319cb9089844d76e65a6cce5bfbd165e698735
Author: Pablo Neira Ayuso [off-list ref]
Date:   Tue Jan 9 01:48:47 2018 +0000

     netfilter: nf_tables: get rid of struct nft_af_info abstraction

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13d38159e00000
start commit:   f5ae2ea6 Fix built-in early-load Intel microcode alignment
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=10338159e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=17d38159e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d9290aeb7e6cf1c4
dashboard link: https://syzkaller.appspot.com/bug?extid=156a04714799b1d480bc
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15a7e669e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11102356e00000

Reported-by: syzbot+156a04714799b1d480bc@syzkaller.appspotmail.com
Fixes: 98319cb90898 ("netfilter: nf_tables: get rid of struct nft_af_info  
abstraction")

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