genirq: Flags mismatch irq 7. 00000000 (ttyS3) vs. 00000000 (pcl816) genirq: Flags mismatch irq 7. 00000000 (ttyS3) vs. 00000000 (pcl816) genirq: Flags mismatch irq 7. 00000000 (ttyS3) vs. 00000000 (pcl816) ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.6.4006/22711 is trying to acquire lock: ffff888055e78428 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfb/0xe20 net/bluetooth/l2cap_core.c:7308 but task is already holding lock: ffffffff8ecd7e28 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_open+0x99/0x10c0 net/bluetooth/rfcomm/core.c:425 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (rfcomm_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 rfcomm_security_cfm+0x95/0x780 net/bluetooth/rfcomm/core.c:2216 hci_auth_cfm include/net/bluetooth/hci_core.h:1857 [inline] hci_auth_complete_evt+0x365/0xba0 net/bluetooth/hci_event.c:3494 hci_event_func net/bluetooth/hci_event.c:7314 [inline] hci_event_packet+0x806/0x1290 net/bluetooth/hci_event.c:7366 hci_rx_work+0x3eb/0xd40 net/bluetooth/hci_core.c:4006 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #1 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 hci_connect_cfm include/net/bluetooth/hci_core.h:1818 [inline] hci_remote_features_evt+0x464/0xa10 net/bluetooth/hci_event.c:3734 hci_event_func net/bluetooth/hci_event.c:7314 [inline] hci_event_packet+0x806/0x1290 net/bluetooth/hci_event.c:7366 hci_rx_work+0x3eb/0xd40 net/bluetooth/hci_core.c:4006 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #0 (&hdev->lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 l2cap_chan_connect+0xfb/0xe20 net/bluetooth/l2cap_core.c:7308 l2cap_sock_connect+0x576/0x750 net/bluetooth/l2cap_sock.c:257 kernel_connect+0x13e/0x1c0 net/socket.c:3555 rfcomm_session_create net/bluetooth/rfcomm/core.c:807 [inline] __rfcomm_dlc_open net/bluetooth/rfcomm/core.c:384 [inline] rfcomm_dlc_open+0x600/0x10c0 net/bluetooth/rfcomm/core.c:427 rfcomm_sock_connect+0x2e9/0x600 net/bluetooth/rfcomm/sock.c:419 __sys_connect_file net/socket.c:2011 [inline] __sys_connect+0x3cb/0x450 net/socket.c:2028 __do_sys_connect net/socket.c:2038 [inline] __se_sys_connect net/socket.c:2035 [inline] __x64_sys_connect+0x76/0x80 net/socket.c:2035 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: &hdev->lock --> hci_cb_list_lock --> rfcomm_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rfcomm_mutex); lock(hci_cb_list_lock); lock(rfcomm_mutex); lock(&hdev->lock); *** DEADLOCK *** 1 lock held by syz.6.4006/22711: #0: ffffffff8ecd7e28 (rfcomm_mutex){+.+.}-{3:3}, at: rfcomm_dlc_open+0x99/0x10c0 net/bluetooth/rfcomm/core.c:425 stack backtrace: CPU: 0 PID: 22711 Comm: syz.6.4006 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x2f8/0x400 kernel/locking/lockdep.c:2215 check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 l2cap_chan_connect+0xfb/0xe20 net/bluetooth/l2cap_core.c:7308 l2cap_sock_connect+0x576/0x750 net/bluetooth/l2cap_sock.c:257 kernel_connect+0x13e/0x1c0 net/socket.c:3555 rfcomm_session_create net/bluetooth/rfcomm/core.c:807 [inline] __rfcomm_dlc_open net/bluetooth/rfcomm/core.c:384 [inline] rfcomm_dlc_open+0x600/0x10c0 net/bluetooth/rfcomm/core.c:427 rfcomm_sock_connect+0x2e9/0x600 net/bluetooth/rfcomm/sock.c:419 __sys_connect_file net/socket.c:2011 [inline] __sys_connect+0x3cb/0x450 net/socket.c:2028 __do_sys_connect net/socket.c:2038 [inline] __se_sys_connect net/socket.c:2035 [inline] __x64_sys_connect+0x76/0x80 net/socket.c:2035 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe595d9e1d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe596c3c028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007fe596026090 RCX: 00007fe595d9e1d9 RDX: 000000000000000a RSI: 0000200000000040 RDI: 0000000000000004 RBP: 00007fe595e35888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe596026128 R14: 00007fe596026090 R15: 00007fff9a23b6d8 hci0: dst ff:ff:ff:ff:ff:ff hci0: dst ff:ff:ff:ff:ff:ff handle 0x0f00 hci0 orig refcnt 13 hci0: conn ffff88805b7d2000 hcon ffff88805b7d2000 orig refcnt 0 hcon ffff88805b7d2000 cache ffff888055e79278, ff:ff:ff:ff:ff:ff hci0 opcode 0x0405 plen 13 hci0: skb len 16 hci0 hcon ffff88805b7d2000 hcon ffff88805b7d2000 conn ffff8880a04df000 hchan ffff888063f60100 conn ffff8880a04df000, psm 0x03, dcid 0x0000 chan ffff88809856c000 orig refcnt 1 hcon ffff88805b7d2000 orig refcnt 1 hcon ffff88805b7d2000 orig refcnt 2 chan ffff88809856c000 BT_BOUND -> BT_CONNECT chan ffff88809856c000 state BT_CONNECT timeout 4000 chan ffff88809856c000 orig refcnt 2 hci0 orig refcnt 14 sk ffff88809856b000 ffff8880304d1400 dlc ffff8880304d1400 session ffff8880298c0300 session ffff8880298c0300 state 3 dlc ffff8880304d1400 state 7 timeout 3000 sk ffff888075954000 sock ffff888076725400, sk ffff888075954000 sock ffff888076725400, sk ffff888075954000 sk ffff888075954000 state 5 socket ffff888076725400 dlc ffff8880304d1400 state 7 dlci 6 err 0 dlc ffff8880304d1400 state 7 dlci 6 err 0 session ffff8880298c0300 dlc ffff8880304d1400 state 7 dlc ffff8880304d1400 state 9 err 0 dlc ffff8880304d1400 refcnt 2 session ffff8880298c0300 session ffff8880298c0300 state 3 timeout 200 sk ffff888075954000 state 9 refcnt 2 sk ffff888075954000 dlc ffff8880304d1400 ffff8880304d1400 kcov: kcov_task_exit: t = ffff88802daebc00, kcov->t = ffff88802daebc00