======================================================
WARNING: possible circular locking dependency detected
6.2.0-next-20230224 #1 Not tainted
------------------------------------------------------
syz-executor.4/273 is trying to acquire lock:
ffff8880143d8880 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: __flush_work+0xdd/0xd80

but task is already holding lock:
ffff8880143d8920 (&hdev->cmd_sync_work_lock){+.+.}-{3:3}, at: hci_cmd_sync_clear+0x45/0x250

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&hdev->cmd_sync_work_lock){+.+.}-{3:3}:
       __mutex_lock+0x133/0x14a0
       hci_cmd_sync_work+0x1e6/0x320
FAULT_INJECTION: forcing a failure.
name fail_page_alloc, interval 1, probability 0, space 0, times 0
       process_one_work+0xa0f/0x1790
CPU: 0 PID: 7285 Comm: syz-executor.3 Not tainted 6.2.0-next-20230224 #1
       worker_thread+0x63b/0x1260
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
       kthread+0x2e9/0x3a0
Call Trace:
       ret_from_fork+0x2c/0x50
 <TASK>

-> #0 (
 dump_stack_lvl+0xc1/0xf0
(work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}
 should_fail_ex+0x4b4/0x5b0
:
       __lock_acquire+0x2d56/0x6380
 prepare_alloc_pages+0x178/0x500
       lock_acquire.part.0+0xea/0x320
 __alloc_pages+0x149/0x510
       __flush_work+0x109/0xd80
       __cancel_work_timer+0x39c/0x4e0
 alloc_pages+0x1a0/0x260
       hci_cmd_sync_clear+0x52/0x250
 get_zeroed_page+0x18/0xb0
       hci_unregister_dev+0xf9/0x410
 mon_alloc_buff+0xed/0x250
       vhci_release+0x80/0x100
 mon_bin_open+0x209/0x4b0
       __fput+0x263/0xa40
       task_work_run+0x174/0x280
 chrdev_open+0x26c/0x6e0
       do_exit+0xad8/0x2800
       do_group_exit+0xd4/0x2a0
       __x64_sys_exit_group+0x3e/0x50
 do_dentry_open+0x6ca/0x12b0
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

other info that might help us debug this:

 Possible unsafe locking scenario:

 path_openat+0x18ad/0x2750
       CPU0                    CPU1
       ----                    ----
  lock(&hdev->cmd_sync_work_lock
);
                               lock(
(work_completion)(&hdev->cmd_sync_work));
 do_filp_open+0x1ba/0x410
                               lock(&hdev->cmd_sync_work_lock
);
  lock((work_completion)(&hdev->cmd_sync_work)
);

 *** DEADLOCK ***

1 lock held by syz-executor.4/273:
 #0: ffff8880143d8920
 (&hdev->cmd_sync_work_lock
){+.+.}-{3:3}
, at: hci_cmd_sync_clear+0x45/0x250

stack backtrace:
 do_sys_openat2+0x171/0x4c0
 __x64_sys_openat+0x143/0x200
 do_syscall_64+0x3f/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f3416812a04
Code: 84 00 00 00 00 00 44 89 54 24 0c e8 96 f9 ff ff 44 8b 54 24 0c 44 89 e2 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 89 44 24 0c e8 c8 f9 ff ff 8b 44
RSP: 002b:00007f3413dd4cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00007f3416812a04
RDX: 0000000000000000 RSI: 00007f3413dd4d60 RDI: 00000000ffffff9c
RBP: 00007f3413dd4d60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007ffc370f86df R14: 00007f3413dd5300 R15: 0000000000022000
 </TASK>
CPU: 1 PID: 273 Comm: syz-executor.4 Not tainted 6.2.0-next-20230224 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2d56/0x6380
 lock_acquire.part.0+0xea/0x320
 __flush_work+0x109/0xd80
 __cancel_work_timer+0x39c/0x4e0
 hci_cmd_sync_clear+0x52/0x250
 hci_unregister_dev+0xf9/0x410
 vhci_release+0x80/0x100
 __fput+0x263/0xa40
 task_work_run+0x174/0x280
 do_exit+0xad8/0x2800
 do_group_exit+0xd4/0x2a0
 __x64_sys_exit_group+0x3e/0x50
 do_syscall_64+0x3f/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f5d5775ab19
Code: Unable to access opcode bytes at 0x7f5d5775aaef.
RSP: 002b:00007ffe92153fc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000165 RCX: 00007f5d5775ab19
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000014 R09: 0000000000000165
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5d577b50c3
R13: 0000000000000000 R14: 0000000000000005 R15: 00007ffe921541b0
 </TASK>
Bluetooth: hci7: unexpected cc 0x0c03 length: 249 > 1
Bluetooth: hci7: unexpected cc 0x1003 length: 249 > 9
Bluetooth: hci7: unexpected cc 0x1001 length: 249 > 9
Bluetooth: hci7: unexpected cc 0x0c23 length: 249 > 4
Bluetooth: hci7: unexpected cc 0x0c25 length: 249 > 3
Bluetooth: hci7: unexpected cc 0x0c38 length: 249 > 2
Bluetooth: hci7: command 0x0409 tx timeout
Bluetooth: hci7: command 0x041b tx timeout
Bluetooth: hci7: command 0x040f tx timeout