======================================================
WARNING: possible circular locking dependency detected
5.10.245 #1 Not tainted
------------------------------------------------------
syz-executor.3/6428 is trying to acquire lock:
ffff88801af6cb78 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xdd/0xa90 kernel/workqueue.c:3050

but task is already holding lock:
ffffffff85620a68 (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:3774
       __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:328
       ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:298

-> #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:4065
       hci_sched_acl_pkt net/bluetooth/hci_core.c:4590 [inline]
       hci_sched_acl net/bluetooth/hci_core.c:4675 [inline]
       hci_tx_work+0xfb4/0x15d0 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:328
       ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:298

-> #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_dev_close+0x175/0x1d0 net/bluetooth/hci_core.c:1865
       hci_sock_ioctl+0x288/0x980 net/bluetooth/hci_sock.c:1067
       sock_do_ioctl+0xd3/0x300 net/socket.c:1066
       sock_ioctl+0x3ef/0x710 net/socket.c:1206
       vfs_ioctl fs/ioctl.c:48 [inline]
       __do_sys_ioctl fs/ioctl.c:753 [inline]
       __se_sys_ioctl fs/ioctl.c:739 [inline]
       __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x67/0xd1

-> #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:277 [inline]
       bg_scan_update+0x82/0x500 net/bluetooth/hci_request.c:2897
       process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282
       worker_thread+0x61d/0x1310 kernel/workqueue.c:2428
       kthread+0x38f/0x470 kernel/kthread.c:328
       ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:298

-> #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:3440
       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/0xb10 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+0x67/0xd1

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.3/6428:
 #0: ffffffff85620a68 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232

stack backtrace:
CPU: 1 PID: 6428 Comm: syz-executor.3 Not tainted 5.10.245 #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:3440
 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/0xb10 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+0x67/0xd1
RIP: 0033:0x7f3595e6fb19
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:00007f35933e5188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3595f82f60 RCX: 00007f3595e6fb19
RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00007f3595ec9f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe1508df0f R14: 00007f35933e5300 R15: 0000000000022000
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 0 PID: 6449 Comm: syz-executor.5 Not tainted 5.10.245 #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:1200
 slab_pre_alloc_hook mm/slab.h:512 [inline]
 slab_alloc_node mm/slub.c:2826 [inline]
 slab_alloc mm/slub.c:2909 [inline]
 kmem_cache_alloc+0x5b/0x310 mm/slub.c:2914
 mem_pool_alloc mm/kmemleak.c:424 [inline]
 create_object.isra.0+0x3a/0xa30 mm/kmemleak.c:581
 kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
 slab_post_alloc_hook mm/slab.h:531 [inline]
 slab_alloc_node mm/slub.c:2901 [inline]
 slab_alloc mm/slub.c:2909 [inline]
 __kmalloc+0x16e/0x390 mm/slub.c:3972
 kmalloc_array include/linux/slab.h:592 [inline]
 kcalloc include/linux/slab.h:603 [inline]
 ext4_find_extent+0xa77/0xd70 fs/ext4/extents.c:906
 ext4_ext_map_blocks+0x1c8/0x5830 fs/ext4/extents.c:4160
 ext4_map_blocks+0x63f/0x1910 fs/ext4/inode.c:673
 ext4_alloc_file_blocks.isra.0+0x2eb/0xb40 fs/ext4/extents.c:4523
 ext4_zero_range fs/ext4/extents.c:4674 [inline]
 ext4_fallocate+0x11fd/0x3850 fs/ext4/extents.c:4773
 vfs_fallocate+0x48f/0xda0 fs/open.c:309
 ioctl_preallocate+0x192/0x210 fs/ioctl.c:494
 file_ioctl fs/ioctl.c:539 [inline]
 do_vfs_ioctl+0xd2f/0x10d0 fs/ioctl.c:732
 __do_sys_ioctl fs/ioctl.c:751 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x10c/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1
RIP: 0033:0x7f459db8eb19
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:00007f459b0e3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f459dca2020 RCX: 00007f459db8eb19
RDX: 0000000020000040 RSI: 0000000040305839 RDI: 0000000000000003
RBP: 00007f459b0e31d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007ffe5093a16f R14: 00007f459b0e3300 R15: 0000000000022000