Bluetooth: hci3: Opcode 0x0406 failed: -4 Bluetooth: hci2: Opcode 0x0c1a failed: -4 Bluetooth: hci2: Opcode 0x0406 failed: -4 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.46/6948 is trying to acquire lock: ffff0000cdf9d840 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}, at: touch_work_lockdep_map+0x70/0x118 kernel/workqueue.c:3953 but task is already holding lock: ffff0000cdf9db38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x78/0x53c net/bluetooth/l2cap_core.c:1763 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&conn->lock#2){+.+.}-{4:4}: __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:614 __mutex_lock kernel/locking/mutex.c:776 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:828 l2cap_info_timeout+0x70/0xb0 net/bluetooth/l2cap_core.c:1669 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3421 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 -> #0 ((work_completion)(&(&conn->info_timer)->work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 touch_work_lockdep_map+0x98/0x118 kernel/workqueue.c:3955 start_flush_work kernel/workqueue.c:4209 [inline] __flush_work+0x4fc/0x8c0 kernel/workqueue.c:4241 __cancel_work_sync kernel/workqueue.c:4397 [inline] cancel_delayed_work_sync+0xc4/0x120 kernel/workqueue.c:4471 l2cap_conn_del+0x37c/0x53c net/bluetooth/l2cap_core.c:1797 l2cap_connect_cfm+0x110/0xdb0 net/bluetooth/l2cap_core.c:7260 hci_connect_cfm include/net/bluetooth/hci_core.h:2131 [inline] hci_conn_failed+0x198/0x340 net/bluetooth/hci_conn.c:1336 hci_abort_conn_sync+0x558/0xbb8 net/bluetooth/hci_sync.c:5721 hci_disconnect_all_sync+0x1b0/0x35c net/bluetooth/hci_sync.c:5744 hci_suspend_sync+0x390/0xa20 net/bluetooth/hci_sync.c:6220 hci_suspend_dev+0x1dc/0x44c net/bluetooth/hci_core.c:2849 hci_suspend_notifier+0xe4/0x2b8 net/bluetooth/hci_core.c:2420 notifier_call_chain+0x190/0x4cc kernel/notifier.c:85 notifier_call_chain_robust kernel/notifier.c:120 [inline] blocking_notifier_call_chain_robust+0x88/0x110 kernel/notifier.c:345 pm_notifier_call_chain_robust+0x34/0x60 kernel/power/main.c:172 snapshot_open+0x17c/0x268 kernel/power/user.c:77 misc_open+0x2d0/0x33c drivers/char/misc.c:163 chrdev_open+0x1b0/0x4b0 fs/char_dev.c:414 do_dentry_open+0x68c/0x1154 fs/open.c:962 vfs_open+0x44/0x2d4 fs/open.c:1094 do_open fs/namei.c:4628 [inline] path_openat+0x2890/0x3114 fs/namei.c:4787 do_filp_open+0x18c/0x36c fs/namei.c:4814 do_sys_openat2+0x11c/0x1f0 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __arm64_sys_openat+0x120/0x158 fs/open.c:1447 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&conn->lock#2); lock((work_completion)(&(&conn->info_timer)->work)); lock(&conn->lock#2); lock((work_completion)(&(&conn->info_timer)->work)); *** DEADLOCK *** 8 locks held by syz.3.46/6948: #0: ffff8000914f3bc8 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x68/0x33c drivers/char/misc.c:125 #1: ffff80008f90aa88 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x5c/0x84 kernel/power/main.c:71 #2: ffff80008f92e330 ((pm_chain_head).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain_robust+0x6c/0x110 kernel/notifier.c:344 #3: ffff0000c8c04ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_suspend_dev+0x1d4/0x44c net/bluetooth/hci_core.c:2848 #4: ffff0000c8c040c0 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x1d4/0xbb8 net/bluetooth/hci_sync.c:5702 #5: ffff800092c4fbc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:2128 [inline] #5: ffff800092c4fbc8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_failed+0x13c/0x340 net/bluetooth/hci_conn.c:1336 #6: ffff0000cdf9db38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x78/0x53c net/bluetooth/l2cap_core.c:1763 #7: ffff80008fa5b6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:330 stack backtrace: CPU: 1 UID: 0 PID: 6948 Comm: syz.3.46 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043 check_noncircular+0x154/0x174 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 touch_work_lockdep_map+0x98/0x118 kernel/workqueue.c:3955 start_flush_work kernel/workqueue.c:4209 [inline] __flush_work+0x4fc/0x8c0 kernel/workqueue.c:4241 __cancel_work_sync kernel/workqueue.c:4397 [inline] cancel_delayed_work_sync+0xc4/0x120 kernel/workqueue.c:4471 l2cap_conn_del+0x37c/0x53c net/bluetooth/l2cap_core.c:1797 l2cap_connect_cfm+0x110/0xdb0 net/bluetooth/l2cap_core.c:7260 hci_connect_cfm include/net/bluetooth/hci_core.h:2131 [inline] hci_conn_failed+0x198/0x340 net/bluetooth/hci_conn.c:1336 hci_abort_conn_sync+0x558/0xbb8 net/bluetooth/hci_sync.c:5721 hci_disconnect_all_sync+0x1b0/0x35c net/bluetooth/hci_sync.c:5744 hci_suspend_sync+0x390/0xa20 net/bluetooth/hci_sync.c:6220 hci_suspend_dev+0x1dc/0x44c net/bluetooth/hci_core.c:2849 hci_suspend_notifier+0xe4/0x2b8 net/bluetooth/hci_core.c:2420 notifier_call_chain+0x190/0x4cc kernel/notifier.c:85 notifier_call_chain_robust kernel/notifier.c:120 [inline] blocking_notifier_call_chain_robust+0x88/0x110 kernel/notifier.c:345 pm_notifier_call_chain_robust+0x34/0x60 kernel/power/main.c:172 snapshot_open+0x17c/0x268 kernel/power/user.c:77 misc_open+0x2d0/0x33c drivers/char/misc.c:163 chrdev_open+0x1b0/0x4b0 fs/char_dev.c:414 do_dentry_open+0x68c/0x1154 fs/open.c:962 vfs_open+0x44/0x2d4 fs/open.c:1094 do_open fs/namei.c:4628 [inline] path_openat+0x2890/0x3114 fs/namei.c:4787 do_filp_open+0x18c/0x36c fs/namei.c:4814 do_sys_openat2+0x11c/0x1f0 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __arm64_sys_openat+0x120/0x158 fs/open.c:1447 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596