Re: [syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in rewrite_old_nodes_pred

[syzbot]

syzbot has bisected this issue to:

commit 03ef80b469d5d83530ce1ce15be78a40e5300f9b
Author: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Date:   Sat Sep 23 22:41:51 2023 +0000

    bcachefs: Ignore unknown mount options

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17afcbc0980000
start commit:   7367539ad4b0 Merge tag 'cxl-fixes-6.9-rc7' of git://git.ke..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=146fcbc0980000
console output: https://syzkaller.appspot.com/x/log.txt?x=106fcbc0980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d2f00edef461175
dashboard link: https://syzkaller.appspot.com/bug?extid=594427aebfefeebe91c6
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12d1b2a0980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=135c2ca8980000

Reported-by: syzbot+594427aebfefeebe91c6@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")

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