====================================================== WARNING: possible circular locking dependency detected 5.15.182-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor/4292 is trying to acquire lock: ffff88807d7c2120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1694 [inline] ffff88807d7c2120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0x142/0x360 net/bluetooth/sco.c:206 but task is already holding lock: ffffffff8d370e08 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline] ffffffff8d370e08 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hci_connect_cfm include/net/bluetooth/hci_core.h:1502 [inline] hci_remote_features_evt+0x5cf/0xa10 net/bluetooth/hci_event.c:3352 hci_event_packet+0x613/0x12f0 net/bluetooth/hci_event.c:6419 hci_rx_work+0x255/0xa10 net/bluetooth/hci_core.c:5160 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #1 (&hdev->lock){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 sco_sock_connect+0x18f/0x910 net/bluetooth/sco.c:597 __sys_connect_file net/socket.c:1923 [inline] __sys_connect+0x389/0x410 net/socket.c:1940 __do_sys_connect net/socket.c:1950 [inline] __se_sys_connect net/socket.c:1947 [inline] __x64_sys_connect+0x76/0x80 net/socket.c:1947 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 lock_sock_nested+0x44/0x100 net/core/sock.c:3251 lock_sock include/net/sock.h:1694 [inline] sco_conn_del+0x142/0x360 net/bluetooth/sco.c:206 hci_disconn_cfm include/net/bluetooth/hci_core.h:1520 [inline] hci_conn_hash_flush+0x107/0x220 net/bluetooth/hci_conn.c:1622 hci_dev_do_close+0x991/0x1030 net/bluetooth/hci_core.c:1795 hci_unregister_dev+0x2d7/0x580 net/bluetooth/hci_core.c:4040 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x234/0x930 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x616/0x20a0 kernel/exit.c:874 do_group_exit+0x12e/0x300 kernel/exit.c:996 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hci_cb_list_lock); lock(&hdev->lock); lock(hci_cb_list_lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO); *** DEADLOCK *** 3 locks held by syz-executor/4292: #0: ffff88802341cff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x5f/0x1030 net/bluetooth/hci_core.c:1737 #1: ffff88802341c078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x3f4/0x1030 net/bluetooth/hci_core.c:1782 #2: ffffffff8d370e08 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1517 [inline] #2: ffffffff8d370e08 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622 stack backtrace: CPU: 0 PID: 4292 Comm: syz-executor Not tainted 5.15.182-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 lock_sock_nested+0x44/0x100 net/core/sock.c:3251 lock_sock include/net/sock.h:1694 [inline] sco_conn_del+0x142/0x360 net/bluetooth/sco.c:206 hci_disconn_cfm include/net/bluetooth/hci_core.h:1520 [inline] hci_conn_hash_flush+0x107/0x220 net/bluetooth/hci_conn.c:1622 hci_dev_do_close+0x991/0x1030 net/bluetooth/hci_core.c:1795 hci_unregister_dev+0x2d7/0x580 net/bluetooth/hci_core.c:4040 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x234/0x930 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x616/0x20a0 kernel/exit.c:874 do_group_exit+0x12e/0x300 kernel/exit.c:996 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f126624941f Code: Unable to access opcode bytes at RIP 0x7f12662493f5. RSP: 002b:00007ffc3747b900 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 0000000000000004 RBX: 00000000000004b1 RCX: 00007f126624941f RDX: 0000000000000004 RSI: 00007ffc3747b9c0 RDI: 00000000000000f8 RBP: 00007ffc3747b96c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000257 R13: 00000000000927c0 R14: 000000000002666e R15: 00007ffc3747b9c0