https://bugzilla.kernel.org/show_bug.cgi?id=199111 --- Comment #3 from Stefan Assmann (sassmann@xxxxxxxxxx) --- Still in 4.17-rc1 [ 16.978701] ====================================================== [ 16.981638] WARNING: possible circular locking dependency detected [ 16.984548] 4.17.0-rc1 #74 Not tainted [ 16.987449] ------------------------------------------------------ [ 16.990308] kworker/u8:0/6 is trying to acquire lock: [ 16.993062] 00000000be6488d6 (bcm_device_lock){+.+.}, at: bcm_recv+0x68/0x110 [hci_uart] [ 16.995928] but task is already holding lock: [ 17.001493] 0000000091379733 (&buf->lock){+.+.}, at: flush_to_ldisc+0x20/0xa0 [ 17.004356] which lock already depends on the new lock. [ 17.012791] the existing dependency chain (in reverse order) is: [ 17.018356] -> #3 (&buf->lock){+.+.}: [ 17.023850] tty_buffer_flush+0x2f/0x90 [ 17.026602] tty_ldisc_flush+0x1d/0x40 [ 17.029347] vt_ioctl+0x56b/0x11c0 [ 17.032086] tty_ioctl+0xef/0x950 [ 17.034839] do_vfs_ioctl+0xa5/0x6e0 [ 17.037586] ksys_ioctl+0x70/0x80 [ 17.037589] __x64_sys_ioctl+0x16/0x20 [ 17.037594] do_syscall_64+0x60/0x200 [ 17.037599] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 17.037601] -> #2 (&tty->ldisc_sem){++++}: [ 17.037609] tty_ldisc_lock+0x12/0x30 [ 17.037612] tty_init_dev+0x90/0x1e0 [ 17.037614] tty_open+0x295/0x450 [ 17.037617] chrdev_open+0xa7/0x1d0 [ 17.037621] do_dentry_open+0x1c7/0x370 [ 17.037623] path_openat+0x592/0xd00 [ 17.037625] do_filp_open+0x9b/0x110 [ 17.037628] do_sys_open+0x1bd/0x250 [ 17.037632] kernel_init_freeable+0x243/0x2d0 [ 17.037636] kernel_init+0xa/0x110 [ 17.037638] ret_from_fork+0x3a/0x50 [ 17.037639] -> #1 (&tty->legacy_mutex){+.+.}: [ 17.037645] tty_init_dev+0x52/0x1e0 [ 17.037649] ttyport_open+0x37/0x150 [ 17.037661] bcm_open+0x88/0x1e0 [hci_uart] [ 17.037667] hci_uart_register_device+0x31/0x200 [hci_uart] [ 17.037671] driver_probe_device+0x30b/0x480 [ 17.037674] __driver_attach+0xbc/0xe0 [ 17.037676] bus_for_each_dev+0x79/0xc0 [ 17.037679] driver_attach_async+0xe/0x40 [ 17.037682] async_run_entry_fn+0x39/0x160 [ 17.037686] process_one_work+0x266/0x6b0 [ 17.037689] worker_thread+0x3a/0x390 [ 17.037691] kthread+0x121/0x140 [ 17.037693] ret_from_fork+0x3a/0x50 [ 17.037694] -> #0 (bcm_device_lock){+.+.}: [ 17.037701] __mutex_lock+0x7f/0xa40 [ 17.037708] bcm_recv+0x68/0x110 [hci_uart] [ 17.037715] hci_uart_receive_buf+0x49/0x70 [hci_uart] [ 17.037717] ttyport_receive_buf+0x50/0xd0 [ 17.037720] flush_to_ldisc+0x81/0xa0 [ 17.037723] process_one_work+0x266/0x6b0 [ 17.037726] worker_thread+0x3a/0x390 [ 17.037728] kthread+0x121/0x140 [ 17.037730] ret_from_fork+0x3a/0x50 [ 17.037731] other info that might help us debug this: [ 17.037732] Chain exists of: bcm_device_lock --> &tty->ldisc_sem --> &buf->lock [ 17.037738] Possible unsafe locking scenario: [ 17.037739] CPU0 CPU1 [ 17.037740] ---- ---- [ 17.037741] lock(&buf->lock); [ 17.037744] lock(&tty->ldisc_sem); [ 17.037746] lock(&buf->lock); [ 17.037748] lock(bcm_device_lock); [ 17.037750] *** DEADLOCK *** [ 17.037753] 3 locks held by kworker/u8:0/6: [ 17.037753] #0: 000000000601b32c ((wq_completion)"events_unbound"){+.+.}, at: process_one_work+0x1da/0x6b0 [ 17.037762] #1: 00000000a7b86b78 ((work_completion)(&buf->work)){+.+.}, at: process_one_work+0x1da/0x6b0 [ 17.037769] #2: 0000000091379733 (&buf->lock){+.+.}, at: flush_to_ldisc+0x20/0xa0 [ 17.037776] stack backtrace: [ 17.037780] CPU: 1 PID: 6 Comm: kworker/u8:0 Not tainted 4.17.0-rc1 #74 [ 17.037782] Hardware name: LENOVO 20C10026UK/20C10026UK, BIOS GWET46WW (1.46) 02/01/2018 [ 17.037787] Workqueue: events_unbound flush_to_ldisc [ 17.037789] Call Trace: [ 17.037801] dump_stack+0x85/0xcb [ 17.037807] print_circular_bug.isra.40+0x1ce/0x1db [ 17.037812] __lock_acquire+0x1299/0x1340 [ 17.037822] ? lock_acquire+0x9f/0x200 [ 17.037825] lock_acquire+0x9f/0x200 [ 17.037834] ? bcm_recv+0x68/0x110 [hci_uart] [ 17.037843] ? bcm_recv+0x68/0x110 [hci_uart] [ 17.037847] __mutex_lock+0x7f/0xa40 [ 17.037855] ? bcm_recv+0x68/0x110 [hci_uart] [ 17.037858] ? trace_hardirqs_on_caller+0xed/0x180 [ 17.037889] ? hci_recv_frame+0x5e/0x90 [bluetooth] [ 17.037897] ? h4_recv_buf+0x184/0x300 [hci_uart] [ 17.037906] ? bcm_recv+0x68/0x110 [hci_uart] [ 17.037914] bcm_recv+0x68/0x110 [hci_uart] [ 17.037922] hci_uart_receive_buf+0x49/0x70 [hci_uart] [ 17.037927] ttyport_receive_buf+0x50/0xd0 [ 17.037932] flush_to_ldisc+0x81/0xa0 [ 17.037937] process_one_work+0x266/0x6b0 [ 17.037943] worker_thread+0x3a/0x390 [ 17.037947] ? process_one_work+0x6b0/0x6b0 [ 17.037950] kthread+0x121/0x140 [ 17.037954] ? kthread_create_worker_on_cpu+0x70/0x70 [ 17.037957] ret_from_fork+0x3a/0x50 -- You are receiving this mail because: You are the assignee for the bug.-- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
