On Thu, Jul 03, 2025 at 01:07:02AM -0700, syzbot wrote: > syzbot has bisected this issue to: > > commit 47dd67532303803a87f43195e088b3b4bcf0454d > Author: Luis Chamberlain <mcgrof@xxxxxxxxxx> > Date: Fri Feb 21 22:38:22 2025 +0000 > > block/bdev: lift block size restrictions to 64k > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15ec33d4580000 > start commit: 50c8770a42fa Add linux-next specific files for 20250702 > git tree: linux-next > final oops: https://syzkaller.appspot.com/x/report.txt?x=17ec33d4580000 > console output: https://syzkaller.appspot.com/x/log.txt?x=13ec33d4580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d831c9dfe03f77ec > dashboard link: https://syzkaller.appspot.com/bug?extid=f4f84b57a01d6b8364ad > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15c93770580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1001aebc580000 > > Reported-by: syzbot+f4f84b57a01d6b8364ad@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 47dd67532303 ("block/bdev: lift block size restrictions to 64k") > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection Odd, I can't see where the null pointer comes from. bdev_getblk() --> __getblk_slow() properly returns NULL and doesn't use the data. But neither does fat_fill_super() on failure. My only suspicion was on fat_msg() but that sb usage seems fine and the goto out_fail seems fine as iput() also doesn't process null inodes and unload_nls() is fine. The return value is also set to -EIO correctly so we don't return NULL actually. I jus tdon't see anything odd on _fat_msg() either. Hrm.. Luis
