Hello, syzbot found the following issue on: HEAD commit: 5b6a4bf680d6 Add linux-next specific files for 20220818 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=10ea94b5080000 kernel config: https://syzkaller.appspot.com/x/.config?x=ead6107a3bbe3c62 dashboard link: https://syzkaller.appspot.com/bug?extid=c933391d8e4089f1f53e compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c933391d8e4089f1f53e@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.0.0-rc1-next-20220818-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/21304 is trying to acquire lock: ffff8880751049a8 ((work_completion)(&(&hdev->discov_off)->work)){+.+.}-{0:0}, at: __flush_work+0xdd/0xae0 kernel/workqueue.c:3066 but task is already holding lock: ffff888075104078 (&hdev->lock){+.+.}-{3:3}, at: hci_unregister_dev+0x347/0x4e0 net/bluetooth/hci_core.c:2687 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&hdev->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747 discov_off+0x88/0x1a0 net/bluetooth/mgmt.c:1033 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #0 ((work_completion)(&(&hdev->discov_off)->work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __flush_work+0x105/0xae0 kernel/workqueue.c:3069 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160 mgmt_index_removed+0x218/0x340 net/bluetooth/mgmt.c:8951 hci_unregister_dev+0x34f/0x4e0 net/bluetooth/hci_core.c:2688 vhci_release+0x7c/0xf0 drivers/bluetooth/hci_vhci.c:568 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xc39/0x2b60 kernel/exit.c:814 do_group_exit+0xd0/0x2a0 kernel/exit.c:944 get_signal+0x238c/0x2610 kernel/signal.c:2858 arch_do_signal_or_restart+0x82/0x2300 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop kernel/entry/common.c:166 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294 do_syscall_64+0x42/0xb0 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->lock); lock((work_completion)(&(&hdev->discov_off)->work)); lock(&hdev->lock); lock((work_completion)(&(&hdev->discov_off)->work)); *** DEADLOCK *** 1 lock held by syz-executor.5/21304: #0: ffff888075104078 (&hdev->lock){+.+.}-{3:3}, at: hci_unregister_dev+0x347/0x4e0 net/bluetooth/hci_core.c:2687 stack backtrace: CPU: 1 PID: 21304 Comm: syz-executor.5 Not tainted 6.0.0-rc1-next-20220818-syzkaller #0 syz-executor.5[21304] cmdline: ��a����� Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: <TASK> __dump_stack lib/dump_stack.c:122 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:140 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __flush_work+0x105/0xae0 kernel/workqueue.c:3069 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160 mgmt_index_removed+0x218/0x340 net/bluetooth/mgmt.c:8951 hci_unregister_dev+0x34f/0x4e0 net/bluetooth/hci_core.c:2688 vhci_release+0x7c/0xf0 drivers/bluetooth/hci_vhci.c:568 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0xdd/0x1a0 kernel/task_work.c:177 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xc39/0x2b60 kernel/exit.c:814 do_group_exit+0xd0/0x2a0 kernel/exit.c:944 get_signal+0x238c/0x2610 kernel/signal.c:2858 arch_do_signal_or_restart+0x82/0x2300 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop kernel/entry/common.c:166 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fce942adfa1 Code: Unable to access opcode bytes at RIP 0x7fce942adf77. RSP: 002b:00007fce954540b0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007fce9439bf80 RCX: 00007fce942adfa1 RDX: 00007fce954540f0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fce942e3189 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007fff7d48034f R14: 00007fce95454300 R15: 0000000000022000 </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.
