====================================================== WARNING: possible circular locking dependency detected 6.1.69-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/5206 is trying to acquire lock: ffff88807dd84dc0 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}, at: __flush_work+0xe5/0xad0 kernel/workqueue.c:3072 but task is already holding lock: ffff88807dd850b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:552 [inline] ffff88807dd850b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_rfkill_set_block+0x129/0x200 net/bluetooth/hci_core.c:956 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&hdev->req_lock){+.+.}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747 hci_dev_do_close net/bluetooth/hci_core.c:552 [inline] hci_rfkill_set_block+0x129/0x200 net/bluetooth/hci_core.c:956 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345 rfkill_fop_write+0x5b7/0x790 net/rfkill/core.c:1286 vfs_write+0x2d9/0xba0 fs/read_write.c:582 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #2 (rfkill_global_mutex){+.+.}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747 rfkill_register+0x30/0x880 net/rfkill/core.c:1057 hci_register_dev+0x4df/0xa40 net/bluetooth/hci_core.c:2655 __vhci_create_device drivers/bluetooth/hci_vhci.c:339 [inline] vhci_create_device+0x3ba/0x6f0 drivers/bluetooth/hci_vhci.c:377 vhci_get_user drivers/bluetooth/hci_vhci.c:434 [inline] vhci_write+0x38b/0x440 drivers/bluetooth/hci_vhci.c:514 call_write_iter include/linux/fs.h:2248 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x7ae/0xba0 fs/read_write.c:584 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (&data->open_mutex){+.+.}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747 vhci_send_frame+0x8a/0xf0 drivers/bluetooth/hci_vhci.c:78 hci_send_frame+0x1ef/0x370 net/bluetooth/hci_core.c:3035 hci_sched_acl_pkt net/bluetooth/hci_core.c:3642 [inline] hci_sched_acl net/bluetooth/hci_core.c:3727 [inline] hci_tx_work+0xec8/0x1ec0 net/bluetooth/hci_core.c:3826 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #0 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __flush_work+0xfe/0xad0 kernel/workqueue.c:3072 hci_dev_close_sync+0x233/0xfc0 net/bluetooth/hci_sync.c:4936 hci_dev_do_close net/bluetooth/hci_core.c:554 [inline] hci_rfkill_set_block+0x131/0x200 net/bluetooth/hci_core.c:956 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345 rfkill_fop_write+0x5b7/0x790 net/rfkill/core.c:1286 vfs_write+0x2d9/0xba0 fs/read_write.c:582 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: (work_completion)(&hdev->tx_work) --> rfkill_global_mutex --> &hdev->req_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hdev->req_lock); lock(rfkill_global_mutex); lock(&hdev->req_lock); lock((work_completion)(&hdev->tx_work)); *** DEADLOCK *** 2 locks held by syz-executor.3/5206: #0: ffffffff8e545328 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x1a5/0x790 net/rfkill/core.c:1278 #1: ffff88807dd850b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:552 [inline] #1: ffff88807dd850b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_rfkill_set_block+0x129/0x200 net/bluetooth/hci_core.c:956 stack backtrace: CPU: 0 PID: 5206 Comm: syz-executor.3 Not tainted 6.1.69-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __flush_work+0xfe/0xad0 kernel/workqueue.c:3072 hci_dev_close_sync+0x233/0xfc0 net/bluetooth/hci_sync.c:4936 hci_dev_do_close net/bluetooth/hci_core.c:554 [inline] hci_rfkill_set_block+0x131/0x200 net/bluetooth/hci_core.c:956 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345 rfkill_fop_write+0x5b7/0x790 net/rfkill/core.c:1286 vfs_write+0x2d9/0xba0 fs/read_write.c:582 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f13e747cce9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f13e82ba0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f13e759bf80 RCX: 00007f13e747cce9 RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007f13e74c947a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f13e759bf80 R15: 00007ffc300a1438