On Tue, Dec 1, 2020 at 10:17 PM Randy Dunlap <rdun...@infradead.org> 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, > >>>> Can you provide the BFS image file that is being mounted? > >>>> (./file0 I think.) > >>>> > >>>> -- > >>>> ~Randy > >>> > >>> > >>> 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); > > > If you/we look at fs/bfs/bfs.h, it says: > > /* In theory BFS supports up to 512 inodes, numbered from 2 (for /) up to 513 > inclusive. > In actual fact, attempting to create the 512th inode (i.e. inode No. 513 > or file No. 511) > will fail with ENOSPC in bfs_add_entry(): the root directory cannot > contain so many entries, counting '..'. > So, mkfs.bfs(8) should really limit its -N option to 511 and not 512. For > now, we just print a warning > if a filesystem is mounted with such "impossible to fill up" number of > inodes */ > > so one question is why does syzkaller try to do this at all?
Solely for kernel testing purposes. > Why not set number-of-inodes to 511 instead of 512 in the BFS image file? > > 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? > > thanks. > -- > ~Randy > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/dc76e615-a2fc-64e1-c979-4699d0d57309%40infradead.org.
