syzbot suspects this issue was fixed by commit:

commit 7e24969022cbd61ddc586f14824fc205661bb124
Author: Ming Lei [off-list ref]
Date:   Mon Aug 17 10:00:55 2020 +0000

    block: allow for_each_bvec to support zero len bvec

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1120f201900000
start commit:   92ed3019 Linux 5.8-rc7
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=84f076779e989e69
dashboard link: https://syzkaller.appspot.com/bug?extid=7d19c5fe6a3f1161abb7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=170f7cbc900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16a25e38900000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: block: allow for_each_bvec to support zero len bvec

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