====================================================== WARNING: possible circular locking dependency detected 6.14.0-rc1-next-20250207-syzkaller-02219-ged58d103e6da-dirty #0 Not tainted ------------------------------------------------------ syz.0.16/6578 is trying to acquire lock: ffff888012844078 (&hdev->lock){+.+.}-{4:4}, at: l2cap_sock_shutdown+0xa41/0x10c0 net/bluetooth/l2cap_sock.c:1363 but task is already holding lock: ffff888079163518 (&chan->lock/1){+.+.}-{4:4}, at: l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline] ffff888079163518 (&chan->lock/1){+.+.}-{4:4}, at: l2cap_sock_shutdown+0x9c9/0x10c0 net/bluetooth/l2cap_sock.c:1360 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&chan->lock/1){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 l2cap_chan_connect+0x7e7/0xeb0 net/bluetooth/l2cap_core.c:7084 l2cap_sock_connect+0x5c9/0x800 net/bluetooth/l2cap_sock.c:256 __sys_connect_file net/socket.c:2045 [inline] __sys_connect+0x288/0x2d0 net/socket.c:2064 __do_sys_connect net/socket.c:2070 [inline] __se_sys_connect net/socket.c:2067 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2067 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&conn->chan_lock){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 l2cap_conn_ready net/bluetooth/l2cap_core.c:1627 [inline] l2cap_connect_cfm+0x5b4/0x1090 net/bluetooth/l2cap_core.c:7288 hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline] hci_remote_features_evt+0x68e/0xac0 net/bluetooth/hci_event.c:3726 hci_event_func net/bluetooth/hci_event.c:7473 [inline] hci_event_packet+0xac2/0x1540 net/bluetooth/hci_event.c:7525 hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4015 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (&hdev->lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 l2cap_sock_shutdown+0xa41/0x10c0 net/bluetooth/l2cap_sock.c:1363 l2cap_sock_release+0x79/0x1d0 net/bluetooth/l2cap_sock.c:1419 __sock_release net/socket.c:647 [inline] sock_close+0xbc/0x240 net/socket.c:1398 __fput+0x3e9/0x9f0 fs/file_table.c:464 task_work_run+0x24f/0x310 kernel/task_work.c:227 get_signal+0x15f7/0x1750 kernel/signal.c:2809 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &hdev->lock --> &conn->chan_lock --> &chan->lock/1 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&chan->lock/1); lock(&conn->chan_lock); lock(&chan->lock/1); lock(&hdev->lock); *** DEADLOCK *** 2 locks held by syz.0.16/6578: #0: ffff888079a38e08 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:877 [inline] #0: ffff888079a38e08 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline] #0: ffff888079a38e08 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x90/0x240 net/socket.c:1398 #1: ffff888079163518 (&chan->lock/1){+.+.}-{4:4}, at: l2cap_chan_lock include/net/bluetooth/l2cap.h:827 [inline] #1: ffff888079163518 (&chan->lock/1){+.+.}-{4:4}, at: l2cap_sock_shutdown+0x9c9/0x10c0 net/bluetooth/l2cap_sock.c:1360 stack backtrace: CPU: 0 UID: 0 PID: 6578 Comm: syz.0.16 Not tainted 6.14.0-rc1-next-20250207-syzkaller-02219-ged58d103e6da-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208 check_prev_add kernel/locking/lockdep.c:3163 [inline] check_prevs_add kernel/locking/lockdep.c:3282 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730 l2cap_sock_shutdown+0xa41/0x10c0 net/bluetooth/l2cap_sock.c:1363 l2cap_sock_release+0x79/0x1d0 net/bluetooth/l2cap_sock.c:1419 __sock_release net/socket.c:647 [inline] sock_close+0xbc/0x240 net/socket.c:1398 __fput+0x3e9/0x9f0 fs/file_table.c:464 task_work_run+0x24f/0x310 kernel/task_work.c:227 get_signal+0x15f7/0x1750 kernel/signal.c:2809 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f32d118cda9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f32d1fa9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffffc RBX: 00007f32d13a5fa0 RCX: 00007f32d118cda9 RDX: 000000000000000e RSI: 0000000020000100 RDI: 0000000000000004 RBP: 00007f32d120e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f32d13a5fa0 R15: 00007ffc760ea6e8