====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor/5634 is trying to acquire lock: ffff8880298c40b8 (&hdev->lock){+.+.}-{4:4}, at: add_ext_adv_params_complete+0xd5/0x890 net/bluetooth/mgmt.c:9253 but task is already holding lock: ffff8880298c47c0 (&hdev->cmd_sync_work_lock){+.+.}-{4:4}, at: hci_cmd_sync_clear+0xfb/0x3f0 net/bluetooth/hci_sync.c:682 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&hdev->cmd_sync_work_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 hci_cmd_sync_lookup_entry net/bluetooth/hci_sync.c:869 [inline] hci_cmd_sync_queue_once+0x42/0x250 net/bluetooth/hci_sync.c:806 hci_update_passive_scan+0x1bf/0x210 net/bluetooth/hci_sync.c:3518 le_conn_complete_evt+0xee9/0x18d0 net/bluetooth/hci_event.c:6106 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:6117 hci_event_func net/bluetooth/hci_event.c:8084 [inline] hci_event_packet+0x67a/0xf10 net/bluetooth/hci_event.c:8138 hci_rx_work+0x2b4/0x1110 net/bluetooth/hci_core.c:4150 process_one_work kernel/workqueue.c:3495 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (&hdev->lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 add_ext_adv_params_complete+0xd5/0x890 net/bluetooth/mgmt.c:9253 _hci_cmd_sync_cancel_entry net/bluetooth/hci_sync.c:667 [inline] hci_cmd_sync_clear+0x1b4/0x3f0 net/bluetooth/hci_sync.c:684 hci_unregister_dev+0x1b4/0x5c0 net/bluetooth/hci_core.c:2697 vhci_release+0x16d/0x1c0 drivers/bluetooth/hci_vhci.c:704 __fput+0x408/0xa40 fs/file_table.c:512 fput_close_sync+0x11f/0x240 fs/file_table.c:618 filp_close_sync+0x6e/0xa0 fs/open.c:1574 close_files fs/file.c:572 [inline] put_files_struct+0x230/0x3c0 fs/file.c:584 do_exit+0x6f0/0x2360 kernel/exit.c:977 do_group_exit+0x22d/0x2f0 kernel/exit.c:1123 get_signal+0x136a/0x1430 kernel/signal.c:3113 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x32c/0x530 arch/x86/entry/syscall_64.c:107 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hdev->cmd_sync_work_lock); lock(&hdev->lock); lock(&hdev->cmd_sync_work_lock); lock(&hdev->lock); *** DEADLOCK *** locks held by syz-executor/5634: 1, on CPU#1: #0: ffff8880298c47c0 (&hdev->cmd_sync_work_lock){+.+.}-{4:4}, at: hci_cmd_sync_clear+0xfb/0x3f0 net/bluetooth/hci_sync.c:682 stack backtrace: CPU: 1 UID: 0 PID: 5634 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 add_ext_adv_params_complete+0xd5/0x890 net/bluetooth/mgmt.c:9253 _hci_cmd_sync_cancel_entry net/bluetooth/hci_sync.c:667 [inline] hci_cmd_sync_clear+0x1b4/0x3f0 net/bluetooth/hci_sync.c:684 hci_unregister_dev+0x1b4/0x5c0 net/bluetooth/hci_core.c:2697 vhci_release+0x16d/0x1c0 drivers/bluetooth/hci_vhci.c:704 __fput+0x408/0xa40 fs/file_table.c:512 fput_close_sync+0x11f/0x240 fs/file_table.c:618 filp_close_sync+0x6e/0xa0 fs/open.c:1574 close_files fs/file.c:572 [inline] put_files_struct+0x230/0x3c0 fs/file.c:584 do_exit+0x6f0/0x2360 kernel/exit.c:977 do_group_exit+0x22d/0x2f0 kernel/exit.c:1123 get_signal+0x136a/0x1430 kernel/signal.c:3113 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x32c/0x530 arch/x86/entry/syscall_64.c:107 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f35a9f69d0e Code: Unable to access opcode bytes at 0x7f35a9f69ce4. RSP: 002b:00007ffe3a7895f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffe00 RBX: 00005555922b8500 RCX: 00007f35a9f69d0e RDX: 0000000000000030 RSI: 00007ffe3a7896f0 RDI: 00000000000000f9 RBP: 00007ffe3a78969c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000258 R13: 000000000000002b R14: 000000000006526d R15: 00007ffe3a7896f0