BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 143s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=76/256 refcnt=77 pending: nsim_dev_trap_report_work, nsim_dev_trap_report_work, nsim_dev_trap_report_work, nsim_dev_trap_report_work, defense_work_handler, defense_work_handler, defense_work_handler, vmstat_shepherd, cache_reap, defense_work_handler, psi_avgs_work, psi_avgs_work, psi_avgs_work, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, check_corruption, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred , rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred, rt6_probe_deferred ====================================================== WARNING: possible circular locking dependency detected 5.4.0-rc7-next-20191115 #0 Not tainted ------------------------------------------------------ syz-executor.1/11333 is trying to acquire lock: ffffffff88fa2080 (console_owner){-.-.}, at: log_next kernel/printk/printk.c:516 [inline] ffffffff88fa2080 (console_owner){-.-.}, at: console_unlock+0x415/0xf00 kernel/printk/printk.c:2460 but task is already holding lock: ffff8880ae836b58 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state kernel/workqueue.c:4767 [inline] ffff8880ae836b58 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state.cold+0x156/0x802 kernel/workqueue.c:4740 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&(&pool->lock)->rlock){-.-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] __queue_work+0x285/0x1280 kernel/workqueue.c:1444 queue_work_on+0x19f/0x210 kernel/workqueue.c:1513 queue_work include/linux/workqueue.h:494 [inline] schedule_work include/linux/workqueue.h:552 [inline] put_pwq kernel/workqueue.c:1113 [inline] put_pwq+0x178/0x1d0 kernel/workqueue.c:1098 put_pwq_unlocked.part.0+0x34/0x70 kernel/workqueue.c:1130 put_pwq_unlocked kernel/workqueue.c:1124 [inline] apply_wqattrs_cleanup.part.0+0xf6/0x160 kernel/workqueue.c:3878 apply_wqattrs_cleanup kernel/workqueue.c:4017 [inline] apply_workqueue_attrs_locked+0xeb/0x140 kernel/workqueue.c:4015 apply_workqueue_attrs+0x31/0x50 kernel/workqueue.c:4046 padata_setup_cpumasks kernel/padata.c:365 [inline] padata_alloc_pd+0x298/0xb60 kernel/padata.c:436 padata_alloc kernel/padata.c:996 [inline] padata_alloc_possible+0x1b6/0x480 kernel/padata.c:1042 pcrypt_init_padata+0x20/0x105 crypto/pcrypt.c:311 pcrypt_init+0x76/0x11b crypto/pcrypt.c:342 do_one_initcall+0x120/0x81a init/main.c:938 do_initcall_level init/main.c:1006 [inline] do_initcalls init/main.c:1014 [inline] do_basic_setup init/main.c:1031 [inline] kernel_init_freeable+0x4ca/0x5b9 init/main.c:1191 kernel_init+0x12/0x1bf init/main.c:1109 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 -> #3 (&pool->lock/1){..-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] __queue_work+0x285/0x1280 kernel/workqueue.c:1444 queue_work_on+0x19f/0x210 kernel/workqueue.c:1513 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+0xb1d/0x1080 drivers/tty/n_tty.c:2356 do_tty_write drivers/tty/tty_io.c:962 [inline] tty_write+0x496/0x7f0 drivers/tty/tty_io.c:1046 __vfs_write+0x8a/0x110 fs/read_write.c:494 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&(&port->lock)->rlock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 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+0x57/0x70 drivers/tty/tty_port.c:387 uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:104 serial8250_tx_chars+0x495/0xaf0 drivers/tty/serial/8250/8250_port.c:1761 serial8250_handle_irq.part.0+0x2a2/0x330 drivers/tty/serial/8250/8250_port.c:1834 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1820 [inline] serial8250_default_handle_irq+0xc0/0x150 drivers/tty/serial/8250/8250_port.c:1850 serial8250_interrupt+0xf1/0x1a0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x15d/0x970 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+0x25e/0x8d0 kernel/irq/chip.c:830 generic_handle_irq_desc include/linux/irqdesc.h:156 [inline] do_IRQ+0xde/0x280 arch/x86/kernel/irq.c:250 ret_from_intr+0x0/0x36 arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x90/0xe0 kernel/locking/spinlock.c:191 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline] uart_write+0x3b6/0x6f0 drivers/tty/serial/serial_core.c:613 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x40e/0x1080 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:962 [inline] tty_write+0x496/0x7f0 drivers/tty/tty_io.c:1046 redirected_tty_write+0xb2/0xc0 drivers/tty/tty_io.c:1067 __vfs_write+0x8a/0x110 fs/read_write.c:494 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&port_lock_key){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 serial8250_console_write+0x253/0x9a0 drivers/tty/serial/8250/8250_port.c:3142 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:587 call_console_drivers kernel/printk/printk.c:1791 [inline] console_unlock+0xb7a/0xf00 kernel/printk/printk.c:2473 vprintk_emit+0x2a0/0x700 kernel/printk/printk.c:1996 vprintk_default+0x28/0x30 kernel/printk/printk.c:2023 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386 printk+0xba/0xed kernel/printk/printk.c:2056 register_console+0x745/0xb50 kernel/printk/printk.c:2798 univ8250_console_init+0x3e/0x4b drivers/tty/serial/8250/8250_core.c:682 console_init+0x461/0x67b kernel/printk/printk.c:2884 start_kernel+0x653/0x943 init/main.c:712 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 -> #0 (console_owner){-.-.}: check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 console_lock_spinning_enable kernel/printk/printk.c:1654 [inline] console_unlock+0x47f/0xf00 kernel/printk/printk.c:2470 vprintk_emit+0x2a0/0x700 kernel/printk/printk.c:1996 vprintk_default+0x28/0x30 kernel/printk/printk.c:2023 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386 printk+0xba/0xed kernel/printk/printk.c:2056 show_pwq+0x154/0x7cb kernel/workqueue.c:4673 show_workqueue_state kernel/workqueue.c:4769 [inline] show_workqueue_state.cold+0x1a6/0x802 kernel/workqueue.c:4740 wq_watchdog_timer_fn+0x511/0x590 kernel/workqueue.c:5783 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0xdca/0x1790 kernel/time/timer.c:1788 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 rep_nop arch/x86/include/asm/processor.h:674 [inline] cpu_relax arch/x86/include/asm/processor.h:679 [inline] irq_work_sync+0xd3/0x1d0 kernel/irq_work.c:194 _free_event+0x89/0x13b0 kernel/events/core.c:4584 put_event+0x47/0x60 kernel/events/core.c:4709 perf_event_release_kernel+0x6d5/0xd70 kernel/events/core.c:4824 perf_release+0x37/0x50 kernel/events/core.c:4834 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x904/0x2e60 kernel/exit.c:817 do_group_exit+0x135/0x360 kernel/exit.c:921 get_signal+0x47c/0x24f0 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe 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 syz-executor.1/11333: #0: ffff8880ae809d50 ((&wq_watchdog_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline] #0: ffff8880ae809d50 ((&wq_watchdog_timer)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394 #1: ffffffff88faccc0 (rcu_read_lock){....}, at: show_workqueue_state+0x0/0x120 kernel/workqueue.c:4638 #2: ffff8880ae836b58 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state kernel/workqueue.c:4767 [inline] #2: ffff8880ae836b58 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state.cold+0x156/0x802 kernel/workqueue.c:4740 #3: ffffffff88fa22e0 (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1716 [inline] #3: ffffffff88fa22e0 (console_lock){+.+.}, at: vprintk_emit+0x283/0x700 kernel/printk/printk.c:1995 stack backtrace: CPU: 0 PID: 11333 Comm: syz-executor.1 Not tainted 5.4.0-rc7-next-20191115 #0 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+0x197/0x210 lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x163/0x172 kernel/locking/lockdep.c:1685 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1809 check_prev_add kernel/locking/lockdep.c:2476 [inline] check_prevs_add kernel/locking/lockdep.c:2581 [inline] validate_chain kernel/locking/lockdep.c:2971 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 console_lock_spinning_enable kernel/printk/printk.c:1654 [inline] console_unlock+0x47f/0xf00 kernel/printk/printk.c:2470 vprintk_emit+0x2a0/0x700 kernel/printk/printk.c:1996 vprintk_default+0x28/0x30 kernel/printk/printk.c:2023 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386 printk+0xba/0xed kernel/printk/printk.c:2056 show_pwq+0x154/0x7cb kernel/workqueue.c:4673 show_workqueue_state kernel/workqueue.c:4769 [inline] show_workqueue_state.cold+0x1a6/0x802 kernel/workqueue.c:4740 wq_watchdog_timer_fn+0x511/0x590 kernel/workqueue.c:5783 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1773 [inline] __run_timers kernel/time/timer.c:1740 [inline] run_timer_softirq+0xdca/0x1790 kernel/time/timer.c:1788 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] RIP: 0010:irq_work_sync+0xd3/0x1d0 kernel/irq_work.c:193 Code: f5 ff 4d 89 e6 4d 89 e5 48 b8 00 00 00 00 00 fc ff df 49 c1 ee 03 41 83 e5 07 49 01 c6 41 83 c5 03 eb 07 e8 7f 87 f5 ff f3 90 78 87 f5 ff be 04 00 00 00 4c 89 e7 e8 ab a6 31 00 41 0f b6 06 RSP: 0018:ffff888055f67858 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff888055e0e0c0 RBX: 0000000000000002 RCX: ffffffff817e51f6 RDX: 0000000000000000 RSI: ffffffff817e51c1 RDI: 0000000000000005 RBP: ffff888055f67878 R08: ffff888055e0e0c0 R09: ffffed101299bc82 R10: ffffed101299bc81 R11: ffff888094cde40b R12: ffff888094cde408 R13: 0000000000000003 R14: ffffed101299bc81 R15: ffff888055f67918 _free_event+0x89/0x13b0 kernel/events/core.c:4584 put_event+0x47/0x60 kernel/events/core.c:4709 perf_event_release_kernel+0x6d5/0xd70 kernel/events/core.c:4824 perf_release+0x37/0x50 kernel/events/core.c:4834 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16 Lost 33 message(s)! workqueue events_highpri: flags=0x10 pwq 1: cpus=0 node=0 flags=0x0 nice=-20 active=1/256 refcnt=3 pending: flush_backlog BAR(2862) workqueue events_power_efficient: flags=0x80 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256 refcnt=5 pending: gc_worker, do_cache_clean, device_uncache_fw_images_work, neigh_periodic_work workqueue mm_percpu_wq: flags=0x8 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update workqueue netns: flags=0xe000a pwq 4: cpus=0-1 flags=0x4 nice=0 active=1/1 refcnt=4 in-flight: 2862:cleanup_net workqueue ipv6_addrconf: flags=0x40008 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1 refcnt=2 pending: addrconf_verify_work pool 4: cpus=0-1 flags=0x4 nice=0 hung=0s workers=8 idle: 271 10705 11342 7 100 21 388