============================================ WARNING: possible recursive locking detected 6.1.94-syzkaller #0 Not tainted -------------------------------------------- kworker/u5:1/4254 is trying to acquire lock: ffff0000d6369938 ((wq_completion)hci2){+.+.}-{0:0}, at: __flush_workqueue+0x120/0x11c4 kernel/workqueue.c:2812 but task is already holding lock: ffff0000d6369938 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock((wq_completion)hci2); lock((wq_completion)hci2); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by kworker/u5:1/4254: #0: ffff0000d6369938 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2265 #1: ffff80001de17c20 ((work_completion)(&hdev->error_reset)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2267 stack backtrace: CPU: 1 PID: 4254 Comm: kworker/u5:1 Not tainted 6.1.94-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Workqueue: hci2 hci_error_reset Call trace: dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 __lock_acquire+0x6310/0x7680 kernel/locking/lockdep.c:5049 lock_acquire+0x26c/0x7cc kernel/locking/lockdep.c:5662 __flush_workqueue+0x14c/0x11c4 kernel/workqueue.c:2812 drain_workqueue+0xb8/0x32c kernel/workqueue.c:2977 destroy_workqueue+0x80/0xa34 kernel/workqueue.c:4423 hci_release_dev+0x118/0x11cc net/bluetooth/hci_core.c:2771 bt_host_release+0x70/0x88 net/bluetooth/hci_sysfs.c:92 device_release+0x8c/0x1ac kobject_cleanup lib/kobject.c:681 [inline] kobject_release lib/kobject.c:712 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x2a8/0x41c lib/kobject.c:729 put_device+0x28/0x40 drivers/base/core.c:3794 hci_dev_put include/net/bluetooth/hci_core.h:1435 [inline] hci_error_reset+0x160/0x35c net/bluetooth/hci_core.c:1063 process_one_work+0x7ac/0x1404 kernel/workqueue.c:2292 worker_thread+0x8e4/0xfec kernel/workqueue.c:2439 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864