hrtimer: interrupt took 27669 ns BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 151s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256 pending: vmstat_shepherd, psi_update_work, cache_reap, check_corruption ====================================================== WARNING: possible circular locking dependency detected 5.1.0-rc6 #79 Not tainted ------------------------------------------------------ ksoftirqd/0/9 is trying to acquire lock: 0000000038e7b405 (console_owner){-.-.}, at: log_next kernel/printk/printk.c:499 [inline] 0000000038e7b405 (console_owner){-.-.}, at: console_unlock+0x3fc/0xed0 kernel/printk/printk.c:2439 but task is already holding lock: 00000000c0b5977e (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state.cold+0x879/0x11dc kernel/workqueue.c:4723 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&(&pool->lock)->rlock){-.-.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] __queue_work+0x23d/0x10e0 kernel/workqueue.c:1449 queue_work_on+0x192/0x200 kernel/workqueue.c:1518 queue_work include/linux/workqueue.h:494 [inline] schedule_work include/linux/workqueue.h:552 [inline] put_pwq kernel/workqueue.c:1122 [inline] put_pwq+0x178/0x1d0 kernel/workqueue.c:1107 put_pwq_unlocked.part.0+0x34/0x70 kernel/workqueue.c:1139 put_pwq_unlocked kernel/workqueue.c:1133 [inline] destroy_workqueue+0x623/0x700 kernel/workqueue.c:4383 do_floppy_init drivers/block/floppy.c:4699 [inline] floppy_async_init+0x2031/0x2183 drivers/block/floppy.c:4717 async_run_entry_fn+0x126/0x570 kernel/async.c:127 process_one_work+0x98e/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 -> #3 (&pool->lock/1){..-.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:329 [inline] __queue_work+0x23d/0x10e0 kernel/workqueue.c:1449 queue_work_on+0x192/0x200 kernel/workqueue.c:1518 queue_work include/linux/workqueue.h:494 [inline] tty_schedule_flip drivers/tty/tty_buffer.c:413 [inline] tty_flip_buffer_push+0xc5/0x100 drivers/tty/tty_buffer.c:556 pty_write+0x1a6/0x200 drivers/tty/pty.c:125 n_tty_write+0xb06/0x1150 drivers/tty/n_tty.c:2356 do_tty_write drivers/tty/tty_io.c:961 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1045 __vfs_write+0x8d/0x110 fs/read_write.c:485 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x14f/0x2d0 fs/read_write.c:599 __do_sys_write fs/read_write.c:611 [inline] __se_sys_write fs/read_write.c:608 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:608 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&(&port->lock)->rlock){-.-.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 tty_port_tty_get+0x22/0x80 drivers/tty/tty_port.c:287 tty_port_default_wakeup+0x16/0x40 drivers/tty/tty_port.c:47 tty_port_tty_wakeup+0x5d/0x70 drivers/tty/tty_port.c:387 uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:103 serial8250_tx_chars+0x4a4/0xb20 drivers/tty/serial/8250/8250_port.c:1806 serial8250_handle_irq.part.0+0x1be/0x2e0 drivers/tty/serial/8250/8250_port.c:1879 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1865 [inline] serial8250_default_handle_irq+0xc5/0x150 drivers/tty/serial/8250/8250_port.c:1895 serial8250_interrupt+0xfb/0x1a0 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x146/0x900 kernel/irq/handle.c:149 handle_irq_event_percpu+0x74/0x160 kernel/irq/handle.c:189 handle_irq_event+0xa7/0x134 kernel/irq/handle.c:206 handle_edge_irq+0x264/0x8e0 kernel/irq/chip.c:822 generic_handle_irq_desc include/linux/irqdesc.h:156 [inline] handle_irq+0x252/0x3d8 arch/x86/kernel/irq_64.c:78 do_IRQ+0x99/0x1d0 arch/x86/kernel/irq.c:246 ret_from_intr+0x0/0x1e arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x95/0xe0 kernel/locking/spinlock.c:184 spin_unlock_irqrestore include/linux/spinlock.h:384 [inline] uart_write+0x3b6/0x6f0 drivers/tty/serial/serial_core.c:615 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x3ff/0x1150 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:961 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1045 redirected_tty_write+0xb2/0xc0 drivers/tty/tty_io.c:1066 __vfs_write+0x8d/0x110 fs/read_write.c:485 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x14f/0x2d0 fs/read_write.c:599 __do_sys_write fs/read_write.c:611 [inline] __se_sys_write fs/read_write.c:608 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:608 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&port_lock_key){-.-.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 serial8250_console_write+0x253/0x9c0 drivers/tty/serial/8250/8250_port.c:3245 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:586 call_console_drivers kernel/printk/printk.c:1774 [inline] console_unlock+0xb44/0xed0 kernel/printk/printk.c:2452 vprintk_emit+0x280/0x6d0 kernel/printk/printk.c:1975 vprintk_default+0x28/0x30 kernel/printk/printk.c:2002 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2035 register_console+0x74d/0xb50 kernel/printk/printk.c:2767 univ8250_console_init+0x3e/0x4b drivers/tty/serial/8250/8250_core.c:681 console_init+0x4f7/0x761 kernel/printk/printk.c:2853 start_kernel+0x574/0x84f init/main.c:675 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #0 (console_owner){-.-.}: check_prevs_add kernel/locking/lockdep.c:2333 [inline] validate_chain kernel/locking/lockdep.c:2714 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 console_lock_spinning_enable kernel/printk/printk.c:1637 [inline] console_unlock+0x466/0xed0 kernel/printk/printk.c:2449 vprintk_emit+0x280/0x6d0 kernel/printk/printk.c:1975 vprintk_default+0x28/0x30 kernel/printk/printk.c:2002 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2035 show_pwq kernel/workqueue.c:4630 [inline] show_workqueue_state.cold+0x9e4/0x11dc kernel/workqueue.c:4725 wq_watchdog_timer_fn+0x516/0x5a0 kernel/workqueue.c:5737 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers kernel/time/timer.c:1681 [inline] __run_timers kernel/time/timer.c:1649 [inline] run_timer_softirq+0xd03/0x1700 kernel/time/timer.c:1696 __do_softirq+0x266/0x95a kernel/softirq.c:293 run_ksoftirqd kernel/softirq.c:655 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:647 smpboot_thread_fn+0x6ab/0xa40 kernel/smpboot.c:164 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 other info that might help us debug this: Chain exists of: console_owner --> &pool->lock/1 --> &(&pool->lock)->rlock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&pool->lock)->rlock); lock(&pool->lock/1); lock(&(&pool->lock)->rlock); lock(console_owner); *** DEADLOCK *** 4 locks held by ksoftirqd/0/9: #0: 000000000fa65e1b ((&wq_watchdog_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:170 [inline] #0: 000000000fa65e1b ((&wq_watchdog_timer)){+.-.}, at: call_timer_fn+0xda/0x720 kernel/time/timer.c:1315 #1: 000000000183de91 (rcu_read_lock_sched){....}, at: show_workqueue_state+0x0/0x120 kernel/workqueue.c:4595 #2: 00000000c0b5977e (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state.cold+0x879/0x11dc kernel/workqueue.c:4723 #3: 00000000c90a8d8b (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1699 [inline] #3: 00000000c90a8d8b (console_lock){+.+.}, at: vprintk_emit+0x267/0x6d0 kernel/printk/printk.c:1974 stack backtrace: CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.1.0-rc6 #79 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1571 check_prev_add.constprop.0+0xf11/0x23c0 kernel/locking/lockdep.c:2220 check_prevs_add kernel/locking/lockdep.c:2333 [inline] validate_chain kernel/locking/lockdep.c:2714 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 console_lock_spinning_enable kernel/printk/printk.c:1637 [inline] console_unlock+0x466/0xed0 kernel/printk/printk.c:2449 vprintk_emit+0x280/0x6d0 kernel/printk/printk.c:1975 vprintk_default+0x28/0x30 kernel/printk/printk.c:2002 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:2035 show_pwq kernel/workqueue.c:4630 [inline] show_workqueue_state.cold+0x9e4/0x11dc kernel/workqueue.c:4725 wq_watchdog_timer_fn+0x516/0x5a0 kernel/workqueue.c:5737 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers kernel/time/timer.c:1681 [inline] __run_timers kernel/time/timer.c:1649 [inline] run_timer_softirq+0xd03/0x1700 kernel/time/timer.c:1696 __do_softirq+0x266/0x95a kernel/softirq.c:293 run_ksoftirqd kernel/softirq.c:655 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:647 smpboot_thread_fn+0x6ab/0xa40 kernel/smpboot.c:164 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 workqueue events_power_efficient: flags=0x80 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=3/256 in-flight: 12:gc_worker pending: do_cache_clean, check_lifetime workqueue mm_percpu_wq: flags=0x8 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 pending: vmstat_update workqueue dm_bufio_cache: flags=0x8 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 pending: work_fn workqueue ipv6_addrconf: flags=0x40008 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1 pending: addrconf_verify_work pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=152s workers=2 idle: 2996