======================================================
WARNING: possible circular locking dependency detected
5.10.200 #1 Not tainted
------------------------------------------------------
syz-executor.5/15450 is trying to acquire lock:
ffff888018174b78 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xdd/0xa90 kernel/workqueue.c:3050

but task is already holding lock:
ffffffff85619468 (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

-> #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/0x22f0 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:3728 [inline]
       __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4954
       lock_acquire kernel/locking/lockdep.c:5565 [inline]
       lock_acquire+0x197/0x470 kernel/locking/lockdep.c:5530
       __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.5/15450:
 #0: ffffffff85619468 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232

stack backtrace:
CPU: 1 PID: 15450 Comm: syz-executor.5 Not tainted 5.10.200 #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:3728 [inline]
 __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4954
 lock_acquire kernel/locking/lockdep.c:5565 [inline]
 lock_acquire+0x197/0x470 kernel/locking/lockdep.c:5530
 __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: 0033:0x7f3519678b19
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:00007f3516bee188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f351978bf60 RCX: 00007f3519678b19
RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 00007f35196d2f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff483b653f R14: 00007f3516bee300 R15: 0000000000022000
mac80211_hwsim hwsim36 wlan1: refused to change device tx_queue_len
mac80211_hwsim hwsim36 wlan1: refused to change device tx_queue_len
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 0 PID: 15476 Comm: syz-executor.7 Not tainted 5.10.200 #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
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail.cold+0x5/0xa lib/fault-inject.c:146
 should_failslab+0x5/0x20 mm/slab_common.c:1193
 slab_pre_alloc_hook mm/slab.h:515 [inline]
 slab_alloc_node mm/slub.c:2821 [inline]
 slab_alloc mm/slub.c:2904 [inline]
 kmem_cache_alloc+0x5b/0x310 mm/slub.c:2909
 mem_pool_alloc mm/kmemleak.c:423 [inline]
 create_object.isra.0+0x3a/0xa20 mm/kmemleak.c:578
 kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
 slab_post_alloc_hook mm/slab.h:534 [inline]
 slab_alloc_node mm/slub.c:2896 [inline]
 kmem_cache_alloc_node+0x169/0x330 mm/slub.c:2932
 __alloc_skb+0x6d/0x5b0 net/core/skbuff.c:198
 alloc_skb include/linux/skbuff.h:1102 [inline]
 __ip_append_data+0x2930/0x3310 net/ipv4/ip_output.c:1116
 ip_append_data net/ipv4/ip_output.c:1335 [inline]
 ip_append_data+0x114/0x1a0 net/ipv4/ip_output.c:1314
 raw_sendmsg+0xaa6/0x29d0 net/ipv4/raw.c:670
 inet_sendmsg+0x11d/0x140 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:651 [inline]
 __sock_sendmsg+0x13c/0x190 net/socket.c:663
 ____sys_sendmsg+0x334/0x870 net/socket.c:2376
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2430
 __sys_sendmmsg+0x195/0x470 net/socket.c:2516
 __do_sys_sendmmsg net/socket.c:2545 [inline]
 __se_sys_sendmmsg net/socket.c:2542 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2542
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x62/0xc7
RIP: 0033:0x7fb31b900b19
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:00007fb318e76188 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fb31ba13f60 RCX: 00007fb31b900b19
RDX: 0000000000000001 RSI: 0000000020002040 RDI: 0000000000000005
RBP: 00007fb318e761d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007fff8395b0ff R14: 00007fb318e76300 R15: 0000000000022000