Re: [syzbot] [mm?] [udf?] KASAN: null-ptr-deref Read in filemap_fault

[syzbot]

syzbot has bisected this issue to:

commit 66dabbb65d673aef40dd17bf62c042be8f6d4a4b
Author: Christoph Hellwig <hch@xxxxxx>
Date:   Tue Mar 7 14:34:10 2023 +0000

    mm: return an ERR_PTR from __filemap_get_folio

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15220608280000
start commit:   865fdb08197e Merge tag 'input-for-v6.4-rc0' of git://git.k..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=17220608280000
console output: https://syzkaller.appspot.com/x/log.txt?x=13220608280000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d1c8518c09009bad
dashboard link: https://syzkaller.appspot.com/bug?extid=48011b86c8ea329af1b9
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=137594c4280000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10cfd602280000

Reported-by: syzbot+48011b86c8ea329af1b9@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 66dabbb65d67 ("mm: return an ERR_PTR from __filemap_get_folio")

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