On Wed 03-05-23 02:23:19, syzbot wrote: > 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 Actually looking into commit 66dabbb65d67 it seems it has two problems - one in filemap_fault() where in: if (IS_ERR(folio)) { if (fpin) goto out_retry; we need to clear folio so that we don't try to folio_put() the error pointer. And another in afs_dir_get_folio() where the changes effectively make that function return ERR_PTR instead of NULL as well which will then confuse afs_edit_dir_add() and other callers (which were not updated). Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
