======================================================
WARNING: possible circular locking dependency detected
5.10.207 #1 Not tainted
------------------------------------------------------
syz-executor.4/74995 is trying to acquire lock:
ffff888009958b78 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xdd/0xa90 kernel/workqueue.c:3050

but task is already holding lock:
ffffffff85619628 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (rfkill_global_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:968 [inline]
       __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109
       rfkill_register+0x36/0xa10 net/rfkill/core.c:1016
       hci_register_dev+0x42e/0xc00 net/bluetooth/hci_core.c:3773
       __vhci_create_device+0x2c8/0x5c0 drivers/bluetooth/hci_vhci.c:129
       vhci_create_device drivers/bluetooth/hci_vhci.c:153 [inline]
       vhci_open_timeout+0x38/0x50 drivers/bluetooth/hci_vhci.c:310
       process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282
       worker_thread+0x61d/0x1310 kernel/workqueue.c:2428
       kthread+0x38f/0x470 kernel/kthread.c:313
       ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299

-> #3 (&data->open_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:968 [inline]
       __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109
       vhci_send_frame+0x63/0xa0 drivers/bluetooth/hci_vhci.c:71
       hci_send_frame+0x1b9/0x320 net/bluetooth/hci_core.c:4060
       hci_sched_acl_pkt net/bluetooth/hci_core.c:4585 [inline]
       hci_sched_acl net/bluetooth/hci_core.c:4670 [inline]
       hci_tx_work+0x10af/0x1660 net/bluetooth/hci_core.c:4741
       process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282
       worker_thread+0x61d/0x1310 kernel/workqueue.c:2428
       kthread+0x38f/0x470 kernel/kthread.c:313
       ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299
serio: Serial port tty23

-> #2 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}:
       __flush_work+0x105/0xa90 kernel/workqueue.c:3053
       hci_dev_do_close+0x131/0x1240 net/bluetooth/hci_core.c:1745
       hci_unregister_dev+0x149/0x430 net/bluetooth/hci_core.c:3849
       vhci_release+0x70/0xf0 drivers/bluetooth/hci_vhci.c:345
       __fput+0x285/0x980 fs/file_table.c:281
       task_work_run+0xe2/0x1a0 kernel/task_work.c:161
       exit_task_work include/linux/task_work.h:32 [inline]
       do_exit+0xb6f/0x2600 kernel/exit.c:858
       do_group_exit+0x125/0x310 kernel/exit.c:980
       get_signal+0x4bc/0x22e0 kernel/signal.c:2751
       arch_do_signal_or_restart+0x2b7/0x1990 arch/x86/kernel/signal.c:805
       handle_signal_work kernel/entry/common.c:145 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
       exit_to_user_mode_prepare+0x10f/0x190 kernel/entry/common.c:199
       syscall_exit_to_user_mode+0x38/0x1e0 kernel/entry/common.c:274
       entry_SYSCALL_64_after_hwframe+0x62/0xc7

-> #1 (&hdev->req_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:968 [inline]
       __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109
       hci_req_sync net/bluetooth/hci_request.c:275 [inline]
       bg_scan_update+0x82/0x500 net/bluetooth/hci_request.c:2895
       process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282
       worker_thread+0x61d/0x1310 kernel/workqueue.c:2428
       kthread+0x38f/0x470 kernel/kthread.c:313
       ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299

-> #0 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:2988 [inline]
       check_prevs_add kernel/locking/lockdep.c:3113 [inline]
       validate_chain kernel/locking/lockdep.c:3729 [inline]
       __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4955
       lock_acquire kernel/locking/lockdep.c:5566 [inline]
       lock_acquire+0x197/0x470 kernel/locking/lockdep.c:5531
       __flush_work+0x105/0xa90 kernel/workqueue.c:3053
       __cancel_work_timer+0x368/0x4c0 kernel/workqueue.c:3144
       hci_request_cancel_all+0x73/0x230 net/bluetooth/hci_request.c:3438
       hci_dev_do_close+0xd9/0x1240 net/bluetooth/hci_core.c:1733
       hci_rfkill_set_block+0x166/0x1a0 net/bluetooth/hci_core.c:2223
       rfkill_set_block+0x1fd/0x540 net/rfkill/core.c:341
       rfkill_fop_write+0x253/0x4b0 net/rfkill/core.c:1240
       vfs_write+0x29a/0xa70 fs/read_write.c:603
       ksys_write+0x1f6/0x260 fs/read_write.c:658
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x62/0xc7

other info that might help us debug this:

Chain exists of:
  (work_completion)(&hdev->bg_scan_update) --> &data->open_mutex --> rfkill_global_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(rfkill_global_mutex);
                               lock(&data->open_mutex);
                               lock(rfkill_global_mutex);
  lock((work_completion)(&hdev->bg_scan_update));

 *** DEADLOCK ***

1 lock held by syz-executor.4/74995:
 #0: ffffffff85619628 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232

stack backtrace:
CPU: 0 PID: 74995 Comm: syz-executor.4 Not tainted 5.10.207 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x167 lib/dump_stack.c:118
 check_noncircular+0x263/0x2e0 kernel/locking/lockdep.c:2123
 check_prev_add kernel/locking/lockdep.c:2988 [inline]
 check_prevs_add kernel/locking/lockdep.c:3113 [inline]
 validate_chain kernel/locking/lockdep.c:3729 [inline]
 __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4955
 lock_acquire kernel/locking/lockdep.c:5566 [inline]
 lock_acquire+0x197/0x470 kernel/locking/lockdep.c:5531
 __flush_work+0x105/0xa90 kernel/workqueue.c:3053
 __cancel_work_timer+0x368/0x4c0 kernel/workqueue.c:3144
 hci_request_cancel_all+0x73/0x230 net/bluetooth/hci_request.c:3438
 hci_dev_do_close+0xd9/0x1240 net/bluetooth/hci_core.c:1733
 hci_rfkill_set_block+0x166/0x1a0 net/bluetooth/hci_core.c:2223
 rfkill_set_block+0x1fd/0x540 net/rfkill/core.c:341
 rfkill_fop_write+0x253/0x4b0 net/rfkill/core.c:1240
 vfs_write+0x29a/0xa70 fs/read_write.c:603
 ksys_write+0x1f6/0x260 fs/read_write.c:658
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x62/0xc7
RIP: 0033:0x7fc60890eb19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc605e84188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc608a21f60 RCX: 00007fc60890eb19
RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00007fc608968f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc499e4edf R14: 00007fc605e84300 R15: 0000000000022000
EXT4-fs (loop0): Unrecognized mount option "��Ջa" or missing value
sg_write: data in/out 253104/8 bytes for SCSI command 0x3f-- guessing data in;
   program syz-executor.3 not setting count and/or reply_len properly
serio: Serial port tty23
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 0, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 1 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 1, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 2 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 2, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 3 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 3, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 4 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 4, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 5 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 5, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 6 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 6, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 7 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 7, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 0, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
blk_update_request: I/O error, dev sr0, sector 1 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev sr0, logical block 1, async page read
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=0s
sr 1:0:0:0: [sr0] tag#0 Sense Key : Not Ready [current] 
sr 1:0:0:0: [sr0] tag#0 Add. Sense: Medium not present
sr 1:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 01 00 00 01 00
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer
sr 1:0:0:0: [sr0] tag#0 unaligned transfer