Hello, syzbot found the following issue on: HEAD commit: 4d6d7ce9baaf Add linux-next specific files for 20230224 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=159b1e44c80000 kernel config: https://syzkaller.appspot.com/x/.config?x=4fe68735401a6111 dashboard link: https://syzkaller.appspot.com/bug?extid=0dc69aab0bf17cdd4092 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/f73e26755a73/disk-4d6d7ce9.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e8a9e1fdaa91/vmlinux-4d6d7ce9.xz kernel image: https://storage.googleapis.com/syzbot-assets/ad213a829368/bzImage-4d6d7ce9.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0dc69aab0bf17cdd4092@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.2.0-next-20230224-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/5079 is trying to acquire lock: ffff888022388880 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: __flush_work+0xdd/0xb60 kernel/workqueue.c:3167 but task is already holding lock: ffff888022388920 (&hdev->cmd_sync_work_lock){+.+.}-{3:3}, at: hci_cmd_sync_clear+0x3c/0x2a0 net/bluetooth/hci_sync.c:653 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&hdev->cmd_sync_work_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747 hci_cmd_sync_work+0x26f/0x450 net/bluetooth/hci_sync.c:287 process_one_work+0x9bf/0x1820 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 -> #0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire.part.0+0x11a/0x370 kernel/locking/lockdep.c:5669 __flush_work+0x109/0xb60 kernel/workqueue.c:3170 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3261 hci_cmd_sync_clear+0x48/0x2a0 net/bluetooth/hci_sync.c:654 hci_unregister_dev+0x16b/0x580 net/bluetooth/hci_core.c:2696 vhci_release+0x80/0xf0 drivers/bluetooth/hci_vhci.c:568 __fput+0x27c/0xa90 fs/file_table.c:321 task_work_run+0x16f/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xb42/0x2b60 kernel/exit.c:869 do_group_exit+0xd4/0x2a0 kernel/exit.c:1019 get_signal+0x2315/0x25b0 kernel/signal.c:2859 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hdev->cmd_sync_work_lock); lock((work_completion)(&hdev->cmd_sync_work)); lock(&hdev->cmd_sync_work_lock); lock((work_completion)(&hdev->cmd_sync_work)); *** DEADLOCK *** 1 lock held by syz-executor.0/5079: #0: ffff888022388920 (&hdev->cmd_sync_work_lock){+.+.}-{3:3}, at: hci_cmd_sync_clear+0x3c/0x2a0 net/bluetooth/hci_sync.c:653 stack backtrace: CPU: 0 PID: 5079 Comm: syz-executor.0 Not tainted 6.2.0-next-20230224-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056 lock_acquire.part.0+0x11a/0x370 kernel/locking/lockdep.c:5669 __flush_work+0x109/0xb60 kernel/workqueue.c:3170 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3261 hci_cmd_sync_clear+0x48/0x2a0 net/bluetooth/hci_sync.c:654 hci_unregister_dev+0x16b/0x580 net/bluetooth/hci_core.c:2696 vhci_release+0x80/0xf0 drivers/bluetooth/hci_vhci.c:568 __fput+0x27c/0xa90 fs/file_table.c:321 task_work_run+0x16f/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xb42/0x2b60 kernel/exit.c:869 do_group_exit+0xd4/0x2a0 kernel/exit.c:1019 get_signal+0x2315/0x25b0 kernel/signal.c:2859 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7ff20608d567 Code: Unable to access opcode bytes at 0x7ff20608d53d. RSP: 002b:00007fffc36b4528 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: fffffffffffffffe RBX: 0000000000000003 RCX: 00007ff20608d567 RDX: 00007fffc36b45fc RSI: 000000000000000a RDI: 00007fffc36b45f0 RBP: 00007fffc36b45f0 R08: 00000000ffffffff R09: 00007fffc36b43c0 R10: 0000555555e77853 R11: 0000000000000246 R12: 00007ff2060e6b24 R13: 00007fffc36b56b0 R14: 0000555555e77810 R15: 00007fffc36b56f0 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
