Cc-ing Linus, Tejun, Andrew [I'll keep the entire lockdep report] On (07/02/18 19:26), Tetsuo Handa wrote: [..] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606834] swapper/0/0 is trying > to acquire lock: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606835] 00000000316e1432 > (console_owner){-.-.}, at: console_unlock+0x1ce/0x8b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606840] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606841] but task is already > holding lock: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606842] 000000009b45dcb4 > (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state+0x3b2/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606847] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606848] which lock already > depends on the new lock. > ... > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606851] the existing > dependency chain (in reverse order) is: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606852] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606852] -> #4 > (&(&pool->lock)->rlock){-.-.}: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606857] > _raw_spin_lock+0x2a/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606858] > __queue_work+0xfb/0x780 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606859] > queue_work_on+0xde/0x110 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606861] > put_pwq+0x85/0x90 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606862] > put_pwq_unlocked.part.29+0x1d/0x30 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606863] > destroy_workqueue+0x2df/0x320 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606865] > tipc_topsrv_stop+0x1a0/0x290 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606866] > tipc_exit_net+0x15/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606867] > ops_exit_list.isra.8+0x4e/0x90 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606869] > cleanup_net+0x219/0x390 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606870] > process_one_work+0x2ec/0x800 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606871] > worker_thread+0x45/0x4d0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606872] > kthread+0x14c/0x170 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606874] > ret_from_fork+0x3a/0x50
I assume this one is pwq->pool->lock -> last_pool->lock ? > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606874] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606875] -> #3 > (&pool->lock/1){-.-.}: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606880] > _raw_spin_lock+0x2a/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606881] > __queue_work+0xfb/0x780 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606882] > queue_work_on+0xde/0x110 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606884] > tty_flip_buffer_push+0x2f/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606885] > pty_write+0xb0/0xc0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606886] > n_tty_write+0x244/0x620 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606887] > tty_write+0x1e3/0x3f0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606888] > __vfs_write+0x54/0x270 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606890] > vfs_write+0xf0/0x230 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606891] > redirected_tty_write+0x61/0xb0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606892] > do_iter_write+0x1ce/0x220 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606893] > vfs_writev+0xb0/0x140 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606895] > do_writev+0x6d/0x120 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606896] > __x64_sys_writev+0x20/0x30 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606897] > do_syscall_64+0x81/0x260 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606899] > entry_SYSCALL_64_after_hwframe+0x49/0xbe So #3 is tty_port->lock -> WQ pool->lock > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606900] -> #2 > (&(&port->lock)->rlock){-.-.}: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606905] > _raw_spin_lock_irqsave+0x56/0x70 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606906] > tty_port_tty_get+0x20/0x60 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606907] > tty_port_default_wakeup+0x15/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606909] > tty_port_tty_wakeup+0x20/0x30 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606910] > uart_write_wakeup+0x26/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606911] > serial8250_tx_chars+0x1ae/0x2d0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606913] > serial8250_handle_irq.part.23+0x108/0x130 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606915] > serial8250_default_handle_irq+0x7a/0x90 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606916] > serial8250_interrupt+0x77/0x110 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606918] > __handle_irq_event_percpu+0x80/0x480 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606919] > handle_irq_event_percpu+0x35/0x90 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606920] > handle_irq_event+0x39/0x60 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606922] > handle_edge_irq+0xa5/0x230 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606923] > handle_irq+0xae/0x120 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606924] > do_IRQ+0x53/0x110 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606925] > ret_from_intr+0x0/0x1e > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606927] > free_unref_page_list+0x333/0x590 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606928] > release_pages+0x44a/0x5c0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606930] > free_pages_and_swap_cache+0x107/0x150 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606931] > tlb_flush_mmu_free+0x4e/0x70 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606932] > arch_tlb_finish_mmu+0x61/0xa0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606934] > tlb_finish_mmu+0x36/0x50 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606935] > exit_mmap+0x10a/0x230 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606936] > mmput+0x92/0x1c0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606937] > do_exit+0x365/0x10b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606938] > do_group_exit+0x60/0x100 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606940] > __x64_sys_exit_group+0x1c/0x20 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606941] > do_syscall_64+0x81/0x260 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606943] > entry_SYSCALL_64_after_hwframe+0x49/0xbe #2 is hard IRQ uart_port->lock -> tty_port->lock > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606943] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606944] -> #1 > (&port_lock_key){-.-.}: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606948] > _raw_spin_lock_irqsave+0x56/0x70 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606950] > serial8250_console_write+0x30c/0x3b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606951] > univ8250_console_write+0x35/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606953] > console_unlock+0x650/0x8b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606954] > register_console+0x339/0x540 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606955] > univ8250_console_init+0x30/0x3a > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606957] > console_init+0x2c6/0x424 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606958] > start_kernel+0x466/0x61f > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606959] > x86_64_start_reservations+0x2a/0x2c > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606961] > x86_64_start_kernel+0x72/0x75 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606962] > secondary_startup_64+0xa5/0xb0 Must be console_sem / console_owner -> uart_port->lock ? > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606963] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606963] -> #0 > (console_owner){-.-.}: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606968] > lock_acquire+0xbf/0x220 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606969] > console_unlock+0x23e/0x8b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606970] > vprintk_emit+0x394/0x680 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606971] > vprintk_default+0x28/0x30 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606973] > vprintk_func+0x57/0xc0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606974] > printk+0x5e/0x7d > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606975] > show_workqueue_state+0x448/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606977] > wq_watchdog_timer_fn+0x1df/0x320 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606978] > call_timer_fn+0xb0/0x420 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606979] > run_timer_softirq+0x2da/0x870 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606981] > __do_softirq+0xd0/0x4fe > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606982] > irq_exit+0xd4/0xe0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606983] > smp_apic_timer_interrupt+0x9a/0x2b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606985] > apic_timer_interrupt+0xf/0x20 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606986] > native_safe_halt+0x6/0x10 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606987] > default_idle+0x2e/0x1a0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606988] > arch_cpu_idle+0x10/0x20 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606990] > default_idle_call+0x1e/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606991] > do_idle+0x205/0x2e0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606992] > cpu_startup_entry+0x6e/0x70 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606993] > rest_init+0xc7/0xd0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606995] > start_kernel+0x5fc/0x61f > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606996] > x86_64_start_reservations+0x2a/0x2c > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606997] > x86_64_start_kernel+0x72/0x75 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606999] > secondary_startup_64+0xa5/0xb0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.606999] #0 is softirq WQ pool->lock -> console_sem / console_owner -> uart_port->lock > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607001] other info that might > help us debug this: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607001] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607002] Chain exists of: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607003] console_owner --> > &pool->lock/1 --> &(&pool->lock)->rlock I don't quite understand how that direct "console_owner -> pool->lock" is possible, there should be uart/tty somewhere in between. For instance: console_owner -> uart_port->lock -> pool->lock -> &(&pool->lock)->rlock But anyway. So we can have [but I'm not completely sure. Maybe lockdep has something else on its mind] something like this: CPU1 CPU0 #IRQ #soft irq serial8250_handle_irq() wq_watchdog_timer_fn() spin_lock(&uart_port->lock) show_workqueue_state() serial8250_rx_chars() spin_lock(&pool->lock) tty_flip_buffer_push() printk() tty_schedule_flip() serial8250_console_write() queue_work() spin_lock(&uart_port->lock) __queue_work() spin_lock(&pool->lock) We need to break the pool->lock -> uart_port->lock chain. - use printk_deferred() to show WQs states [show_workqueue_state() is a timer callback, so local IRQs are enabled]. But show_workqueue_state() is also available via sysrq. - what Alan Cox suggested: use spin_trylock() in serial8250_console_write() and just discard (do not print anything on console) console->writes() that can deadlock us [uart_port->lock is already locked]. This basically means that sometimes there will be no output on a serial console, or there will be missing line. Which kind of contradicts the purpose of print out. We are facing the risk of no output on serial consoles in both case. Thus there must be some other way out of this. Any thoughts? > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607009] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607010] Possible unsafe > locking scenario: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607011] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607012] CPU0 > CPU1 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607014] ---- > ---- > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607014] > lock(&(&pool->lock)->rlock); > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607017] > lock(&pool->lock/1); > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607021] > lock(&(&pool->lock)->rlock); > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607024] lock(console_owner); > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607026] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607027] *** DEADLOCK *** > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607027] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607028] 4 locks held by > swapper/0/0: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607029] #0: 00000000acb744a0 > ((&wq_watchdog_timer)){+.-.}, at: call_timer_fn+0x0/0x420 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607034] #1: 00000000918be876 > (rcu_read_lock_sched){....}, at: show_workqueue_state+0x0/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607040] #2: 000000009b45dcb4 > (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state+0x3b2/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607045] #3: 000000005fd39989 > (console_lock){+.+.}, at: vprintk_emit+0x386/0x680 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607050] > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607051] stack backtrace: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607053] CPU: 0 PID: 0 Comm: > swapper/0 Tainted: G O 4.18.0-rc3 #643 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607056] Hardware name: > VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS > 6.00 05/19/2017 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607057] Call Trace: > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607058] <IRQ> > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607059] dump_stack+0xe9/0x148 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607061] > print_circular_bug.isra.39+0x1f3/0x201 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607062] > __lock_acquire+0x135f/0x1400 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607063] > lock_acquire+0xbf/0x220 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607065] ? > console_unlock+0x215/0x8b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607066] ? > lock_acquire+0xbf/0x220 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607067] ? > console_unlock+0x1ce/0x8b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607068] > console_unlock+0x23e/0x8b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607070] ? > console_unlock+0x1ce/0x8b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607071] > vprintk_emit+0x394/0x680 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607072] > vprintk_default+0x28/0x30 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607073] > vprintk_func+0x57/0xc0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607074] printk+0x5e/0x7d > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607076] > show_workqueue_state+0x448/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607077] ? > wq_watchdog_timer_fn+0x1a6/0x320 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607078] > wq_watchdog_timer_fn+0x1df/0x320 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607080] ? > show_workqueue_state+0x900/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607081] ? > show_workqueue_state+0x900/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607082] > call_timer_fn+0xb0/0x420 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607084] ? > show_workqueue_state+0x900/0x900 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607085] > run_timer_softirq+0x2da/0x870 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607086] > __do_softirq+0xd0/0x4fe > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607087] irq_exit+0xd4/0xe0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607089] > smp_apic_timer_interrupt+0x9a/0x2b0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607090] > apic_timer_interrupt+0xf/0x20 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607091] </IRQ> > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607092] RIP: > 0010:native_safe_halt+0x6/0x10 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607093] Code: 53 18 fe 65 48 > 8b 04 25 40 5e 01 00 f0 80 48 02 20 48 8b 00 a8 08 0f 84 57 ff ff ff eb a6 90 > 90 90 90 90 90 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 > f4 5d c3 90 90 90 90 90 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607135] RSP: > 0018:ffffffff84003df8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607138] RAX: ffffffff8406d7c0 > RBX: 0000000000000000 RCX: 0000000000000000 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607140] RDX: ffffffff8406d7c0 > RSI: 0000000000000001 RDI: ffffffff8406d7c0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607142] RBP: ffffffff84003df8 > R08: 0000000000000001 R09: 0000000000000000 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607144] R10: 0000000000000000 > R11: 0000000000000000 R12: 0000000000000000 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607146] R13: 0000000000000000 > R14: 0000000000000000 R15: ffffffff84098920 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607148] ? > trace_hardirqs_on+0xd/0x10 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607149] > default_idle+0x2e/0x1a0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607150] > arch_cpu_idle+0x10/0x20 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607151] > default_idle_call+0x1e/0x40 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607152] do_idle+0x205/0x2e0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607154] ? do_idle+0xf9/0x2e0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607155] > cpu_startup_entry+0x6e/0x70 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607156] rest_init+0xc7/0xd0 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607158] ? > trace_event_define_fields_vector_alloc_managed+0x8b/0x8b > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607159] > start_kernel+0x5fc/0x61f > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607161] > x86_64_start_reservations+0x2a/0x2c > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607162] > x86_64_start_kernel+0x72/0x75 > 2018-07-02 12:13:13 192.168.159.129:6666 [ 151.607163] > secondary_startup_64+0xa5/0xb0 > 2018-07-02 12:13:44 192.168.159.129:6666 [ 182.238928] BUG: workqueue lockup > - pool cpus=2 node=0 flags=0x0 nice=0 stuck for 92s! > 2018-07-02 12:13:44 192.168.159.129:6666 [ 182.241803] Showing busy > workqueues and worker pools: > 2018-07-02 12:13:44 192.168.159.129:6666 [ 182.243616] workqueue > mm_percpu_wq: flags=0x8 > 2018-07-02 12:13:44 192.168.159.129:6666 [ 182.245141] pwq 4: cpus=2 > node=0 flags=0x0 nice=0 active=1/256 > 2018-07-02 12:13:44 192.168.159.129:6666 [ 182.247130] pending: > vmstat_update > 2018-07-02 12:14:11 192.168.159.129:6666 [ 209.030165] INFO: rcu_sched > detected stalls on CPUs/tasks: > 2018-07-02 12:14:11 192.168.159.129:6666 [ 209.032175] 2-...0: (0 > ticks this GP) idle=0be/1/4611686018427387904 softirq=5544/5544 fqs=27833 > 2018-07-02 12:14:11 192.168.159.129:6666 [ 209.035069] (detected by 3, > t=120007 jiffies, g=2553, c=2552, q=1155) > 2018-07-02 12:14:11 192.168.159.129:6666 [ 209.037220] Sending NMI from CPU > 3 to CPUs 2: -ss