syzbot has bisected this bug to:

commit bc389fd101e57b36aacfaec2df8fe479eabb44ea
Author: David S. Miller [off-list ref]
Date:   Tue Jul 2 21:12:30 2019 +0000

     Merge branch 'macsec-fix-some-bugs-in-the-receive-path'

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=125c5c4c600000
start commit:   459c5fb4 Merge branch 'mscc-PTP-support'
git tree:       net-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=115c5c4c600000
console output: https://syzkaller.appspot.com/x/log.txt?x=165c5c4c600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d4cf1ffb87d590d7
dashboard link: https://syzkaller.appspot.com/bug?extid=eb349eeee854e389c36d
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=111849e2600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1442c25a600000

Reported-by: syzbot+eb349eeee854e389c36d@syzkaller.appspotmail.com
Fixes: bc389fd101e5 ("Merge  
branch 'macsec-fix-some-bugs-in-the-receive-path'")

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