On 12/1/20 1:17 PM, Randy Dunlap wrote: > On 11/30/20 11:47 PM, Dmitry Vyukov wrote: >> On Tue, Dec 1, 2020 at 2:03 AM Randy Dunlap <rdun...@infradead.org> wrote: >>> >>> On 11/30/20 12:43 AM, Dmitry Vyukov wrote: >>>> On Mon, Nov 30, 2020 at 5:29 AM Randy Dunlap <rdun...@infradead.org> wrote: >>>>> >>>>> On 11/27/20 4:32 AM, syzbot wrote: >>>>>> Hello, >>>>>> >>>>>> syzbot found the following issue on: >>>>>> >>>>>> HEAD commit: 418baf2c Linux 5.10-rc5 >>>>>> git tree: upstream >>>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=171555b9500000 >>>>>> kernel config: >>>>>> https://syzkaller.appspot.com/x/.config?x=b81aff78c272da44 >>>>>> dashboard link: >>>>>> https://syzkaller.appspot.com/bug?extid=3fd34060f26e766536ff >>>>>> compiler: gcc (GCC) 10.1.0-syz 20200507 >>>>>> >>>>>> Unfortunately, I don't have any reproducer for this issue yet. >>>>>> >>>>>> IMPORTANT: if you fix the issue, please add the following tag to the >>>>>> commit: >>>>>> Reported-by: syzbot+3fd34060f26e76653...@syzkaller.appspotmail.com >>>>>> >>>>>> BFS-fs: bfs_fill_super(): loop5 is unclean, continuing >>>>>> BFS-fs: bfs_fill_super(): WARNING: filesystem loop5 was created with 512 >>>>>> inodes, the real maximum is 511, mounting anyway >>>>>> BFS-fs: bfs_fill_super(): Last block not available on loop5: 120 >>>>>> BFS-fs: bfs_fill_super(): loop5 is unclean, continuing >>>>>> BFS-fs: bfs_fill_super(): WARNING: filesystem loop5 was created with 512 >>>>>> inodes, the real maximum is 511, mounting anyway >>>>>> BFS-fs: bfs_fill_super(): Last block not available on loop5: 120 >>>>>> >>>>>> >>>>>> --- >>>>>> This report is generated by a bot. It may contain errors. >>>>>> See https://goo.gl/tpsmEJ for more information about syzbot. >>>>>> syzbot engineers can be reached at syzkal...@googlegroups.com. >>>>>> >>>>>> syzbot will keep track of this issue. See: >>>>>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
... >>>> Hi Randy, >>>> >>>> I see this bug was reported with a reproducer: >>>> https://syzkaller.appspot.com/bug?id=a32ebd5db2f7c957b82cf54b97bdecf367bf0421 >>>> I assume it's a dup of this one. >>> >>> Sure, looks the same. >>> >>>> If you need the image itself, you can dump it to a file in the C >>>> reproducer inside of syz_mount_image before mount call. >>> >>> Yes, got that. >>> >>> What outcome or result are you looking for here? >>> Or what do you see as the problem? >> >> Hi Randy, >> >> "WARNING:" in kernel output is supposed to mean a kernel source bug. >> Presence of that kernel bug is what syzbot has reported. >> >> Note: the bug may be a misuse of the "WARNING:" for invalid user >> inputs in output as well :) > > > [adding Al Viro] > > Hi Dmitry, > > I expect that the "WARNING:" message is being interpreted incorrectly here, > but that's a minor issue IMO. > > if (info->si_lasti == BFS_MAX_LASTI) > printf("WARNING: filesystem %s was created with 512 inodes, the > real maximum is 511, mounting anyway\n", s->s_id); > ... > > > However, in testing this, I see that the BFS image is not mounted > on /dev/loop# at all. > > 'mount' says: > > # mount -t bfs -o loop bfsfilesyz000.img /mnt/stand > mount: /mnt/stand: mount(2) system call failed: Not a directory. > > (but it is a directory) > > and I have tracked that down to fs/namespace.c::graft_tree() > returning -ENOTDIR, but I don't know why that is happening. > > > Al, can you provide any insights on this? OK, with Al's help, here is the situation. If I use a regular file instead of a directory, the mount command succeeds. The printk() from fs/bfs/inode.c that uses the WARNING: string is not a WARN() or WARN_ON(). It's just a printk(). <linux/asm-generic/bug.h> says: * Do not include "BUG"/"WARNING" in format strings manually to make these * conditions distinguishable from kernel issues. so if I change fs/bfs/inode.c to use "warning:" or "Warning," or "Note:", this little problem should go away. Is that correct? thanks. -- ~Randy
