overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
======================================================
overlayfs: filesystem on './bus' not supported as upperdir
WARNING: possible circular locking dependency detected
4.14.184-syzkaller #0 Not tainted
------------------------------------------------------
overlayfs: failed to resolve './file1': -2
syz-executor.2/19356 is trying to acquire lock:
 (&ovl_i_mutex_dir_key[depth]#2){++++}, at: [<ffffffff818f83f7>] iterate_dir+0x387/0x5e0 fs/readdir.c:43

but task is already holding lock:
 (sb_writers#3){.+.+}, at: [<ffffffff8192670a>] sb_start_write include/linux/fs.h:1549 [inline]
 (sb_writers#3){.+.+}, at: [<ffffffff8192670a>] mnt_want_write+0x3a/0xb0 fs/namespace.c:386

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#3){.+.+}:
       percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
       percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
       __sb_start_write+0x1a1/0x2e0 fs/super.c:1363
       sb_start_write include/linux/fs.h:1549 [inline]
       mnt_want_write+0x3a/0xb0 fs/namespace.c:386
       ovl_do_remove+0x65/0xb00 fs/overlayfs/dir.c:759
       vfs_rmdir fs/namei.c:3908 [inline]
       vfs_rmdir+0x209/0x400 fs/namei.c:3886
       do_rmdir+0x2d1/0x340 fs/namei.c:3968
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       entry_SYSCALL_64_after_hwframe+0x46/0xbb

-> #0 (&ovl_i_mutex_dir_key[depth]#2){++++}:
       lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
       down_write_killable+0x37/0xb0 kernel/locking/rwsem.c:68
       iterate_dir+0x387/0x5e0 fs/readdir.c:43
       ovl_dir_read fs/overlayfs/readdir.c:306 [inline]
       ovl_dir_read_merged+0x2cb/0x440 fs/overlayfs/readdir.c:365
       ovl_check_empty_dir+0x6e/0x200 fs/overlayfs/readdir.c:870
       ovl_check_empty_and_clear+0x74/0xe0 fs/overlayfs/dir.c:306
       ovl_remove_and_whiteout fs/overlayfs/dir.c:647 [inline]
       ovl_do_remove+0x563/0xb00 fs/overlayfs/dir.c:775
       vfs_rmdir fs/namei.c:3908 [inline]
       vfs_rmdir+0x209/0x400 fs/namei.c:3886
       do_rmdir+0x2d1/0x340 fs/namei.c:3968
       do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
       entry_SYSCALL_64_after_hwframe+0x46/0xbb

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_writers#3);
                               lock(&ovl_i_mutex_dir_key[depth]#2);
                               lock(sb_writers#3);
  lock(&ovl_i_mutex_dir_key[depth]#2);

 *** DEADLOCK ***

4 locks held by syz-executor.2/19356:
 #0:  (sb_writers#16){.+.+}, at: [<ffffffff8192670a>] sb_start_write include/linux/fs.h:1549 [inline]
 #0:  (sb_writers#16){.+.+}, at: [<ffffffff8192670a>] mnt_want_write+0x3a/0xb0 fs/namespace.c:386
 #1:  (&ovl_i_mutex_dir_key[depth]#3/1){+.+.}, at: [<ffffffff818f004e>] inode_lock_nested include/linux/fs.h:754 [inline]
 #1:  (&ovl_i_mutex_dir_key[depth]#3/1){+.+.}, at: [<ffffffff818f004e>] do_rmdir+0x1de/0x340 fs/namei.c:3956
 #2:  (&ovl_i_mutex_dir_key[depth]#3){++++}, at: [<ffffffff818e6ad2>] inode_lock include/linux/fs.h:719 [inline]
 #2:  (&ovl_i_mutex_dir_key[depth]#3){++++}, at: [<ffffffff818e6ad2>] vfs_rmdir fs/namei.c:3897 [inline]
 #2:  (&ovl_i_mutex_dir_key[depth]#3){++++}, at: [<ffffffff818e6ad2>] vfs_rmdir+0xd2/0x400 fs/namei.c:3886
 #3:  (sb_writers#3){.+.+}, at: [<ffffffff8192670a>] sb_start_write include/linux/fs.h:1549 [inline]
 #3:  (sb_writers#3){.+.+}, at: [<ffffffff8192670a>] mnt_want_write+0x3a/0xb0 fs/namespace.c:386

stack backtrace:
CPU: 1 PID: 19356 Comm: syz-executor.2 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_circular_bug.isra.0.cold+0x2dc/0x425 kernel/locking/lockdep.c:1258
 check_prev_add kernel/locking/lockdep.c:1905 [inline]
 check_prevs_add kernel/locking/lockdep.c:2022 [inline]
 validate_chain kernel/locking/lockdep.c:2464 [inline]
 __lock_acquire+0x3057/0x42a0 kernel/locking/lockdep.c:3491
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
 down_write_killable+0x37/0xb0 kernel/locking/rwsem.c:68
 iterate_dir+0x387/0x5e0 fs/readdir.c:43
 ovl_dir_read fs/overlayfs/readdir.c:306 [inline]
 ovl_dir_read_merged+0x2cb/0x440 fs/overlayfs/readdir.c:365
 ovl_check_empty_dir+0x6e/0x200 fs/overlayfs/readdir.c:870
 ovl_check_empty_and_clear+0x74/0xe0 fs/overlayfs/dir.c:306
 ovl_remove_and_whiteout fs/overlayfs/dir.c:647 [inline]
 ovl_do_remove+0x563/0xb00 fs/overlayfs/dir.c:775
 vfs_rmdir fs/namei.c:3908 [inline]
 vfs_rmdir+0x209/0x400 fs/namei.c:3886
 do_rmdir+0x2d1/0x340 fs/namei.c:3968
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007fa66bbcfc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00000000004fc3c0 RCX: 000000000045ca69
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000280
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008c7 R14: 00000000004cba1d R15: 00007fa66bbd06d4
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
overlayfs: unrecognized mount option "./file1" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
CIFS VFS: Malformed UNC in devname.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "l���EK[M�����o�^qz�u��@W'�E΢~�Z��Aˍ*��z��b�r���/��.-�gjv�u�$�;h���T�q�C���
?
Q�3��+D�sUb@�]������<" or missing value
overlayfs: unrecognized mount option "upperd
" or missing value
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'.
CIFS VFS: Malformed UNC in devname.
overlayfs: unrecognized mount option "l���EK[M�����o�^qz�u��@W'�E΢~�Z��Aˍ*��z��b�r���/��.-�gjv�u�$�;h���T�q�C���
?
Q�3��+D�sUb@�]������<" or missing value
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: unrecognized mount option "upperd
" or missing value
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "upperdiruʺ=./bus" or missing value
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "upperdiruʺ=./bus" or missing value
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: unrecognized mount option "./file1" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
overlayfs: unrecognized mount option "./file1" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: failed to resolve './file0': -2
overlayfs: failed to resolve './file0': -2
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "l�weUdir=.:file0;�W/?|���Ag�g�ÜJ�^b��DF/�E=��_��Z��no
C�����HAD�d�2~�P�����R��3���
�X#:�;�N̉{n��}�Fy���v$*]�����t" or missing value
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
overlayfs: unrecognized mount option "00000000000000000000003" or missing value
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "00000000000000000000003" or missing value
overlayfs: unrecognized mount option "l�weUdir=.:file0;�W/?|���Ag�g�ÜJ�^b��DF/�E=��_��Z��no
C�����HAD�d�2~�P�����R��3���
�X#:�;�N̉{n��}�Fy���v$*]�����t" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.1'.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "./file1" or missing value
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: failed to resolve 'file0�ED-*�~�GD-�=��*N5�k�v���JcB�=�
': -2
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: filesystem on './bus' not supported as upperdir
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: failed to resolve 'file0�ED-*�~�GD-�=��*N5�k�v���JcB�=�
': -2
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
overlayfs: unrecognized mount option "6��zD�'�Q�" or missing value
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "6��zD�'�Q�" or missing value
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "workdirz��;ile1" or missing value
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: unrecognized mount option "workdirz��;ile1" or missing value
overlayfs: unrecognized mount option "lnwerdiz=.|�:�il3�9J��i3��ևjo�#?�n�>H�[�.��ό��Cr$]�X��B�
%�@1](VJٚ��h" or missing value
hfs: gid requires an argument
hfs: unable to parse mount options
overlayfs: unrecognized mount option "lnwerdiz=.|�:�il3�9J��i3��ևjo�#?�n�>H�[�.��ό��Cr$]�X��B�
%�@1](VJٚ��h" or missing value
overlayfs: unrecognized mount option "lnwerdiz=.|�:�il3�9J��i3��ևjo�#?�n�>H�[�.��ό��Cr$]�X��B�
%�@1](VJٚ��h" or missing value
hfs: gid requires an argument
hfs: unable to parse mount options
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "lnwerdiz=.|�:�il3�9J��i3��ևjo�#?�n�>H�[�.��ό��Cr$]�X��B�
%�@1](VJٚ��h" or missing value
overlayfs: failed to resolve './file0��(.��f=zD�'�Q�': -2
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: failed to resolve './file0��(.��f=zD�'�Q�': -2
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "low" or missing value
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
8021q: adding VLAN 0 to HW filter on device bond0
overlayfs: unrecognized mount option "low" or missing value
overlayfs: unrecognized mount option "0" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: failed to resolve 'file0-�������JO�7�بu�܂�+�x�_Z�;�U�ꝱg���
Yצ{|}����زV�"H�': -2
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: failed to resolve 'file0-�������JO�7�بu�܂�+�x�_Z�;�U�ꝱg���
Yצ{|}����زV�"H�': -2
overlayfs: filesystem on './bus' not supported as upperdir
libceph: mon0 [::6]:6789 socket closed (con state CONNECTING)
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "0" or missing value
overlayfs: unrecognized mount option "loD<rdir=.:file0" or missing value
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "./file1" or missing value
overlayfs: unrecognized mount option "loD<rdir=.:file0" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "./file1" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on '.' does not support file handles, falling back to index=off.
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: maximum fs stacking depth exceeded
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: unrecognized mount option "./file1" or missing value
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: filesystem on './bus' not supported as upperdir
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.