BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 261s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=3/256 refcnt=4 pending: defense_work_handler, free_obj_work, cache_reap ====================================================== WARNING: possible circular locking dependency detected 5.5.0-rc5-syzkaller #0 Not tainted ------------------------------------------------------ swapper/0/0 is trying to acquire lock: ffffffff8999a700 (console_owner){-.-.}, at: log_next kernel/printk/printk.c:516 [inline] ffffffff8999a700 (console_owner){-.-.}, at: console_unlock+0x415/0xf00 kernel/printk/printk.c:2460 but task is already holding lock: ffff8880ae936b58 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state kernel/workqueue.c:4767 [inline] ffff8880ae936b58 (&(&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+0x120/0x820 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/0x570 init/main.c:1202 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+0x24/0x100 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x16/0x40 drivers/tty/tty_port.c:47 tty_port_tty_wakeup+0x57/0x70 drivers/tty/tty_port.c:388 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+0x261/0x2b0 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 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 start_secondary+0x2f4/0x410 arch/x86/kernel/smpboot.c:264 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 -> #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 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x904/0x943 init/main.c:784 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 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 swapper/0/0: #0: ffffc90000007d50 ((&wq_watchdog_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline] #0: ffffc90000007d50 ((&wq_watchdog_timer)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394 #1: ffffffff899a5340 (rcu_read_lock){....}, at: show_workqueue_state+0x0/0x120 kernel/workqueue.c:4638 #2: ffff8880ae936b58 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state kernel/workqueue.c:4767 [inline] #2: ffff8880ae936b58 (&(&pool->lock)->rlock){-.-.}, at: show_workqueue_state.cold+0x156/0x802 kernel/workqueue.c:4740 #3: ffffffff8999a960 (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1716 [inline] #3: ffffffff8999a960 (console_lock){+.+.}, at: vprintk_emit+0x283/0x700 kernel/printk/printk.c:1995 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc5-syzkaller #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:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 Code: e8 bb db f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 24 4d 51 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 14 4d 51 00 fb f4 cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 be 8a 8b f9 e8 89 RSP: 0018:ffffffff89807ce8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff132669e RBX: ffffffff8987a140 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff8987a9d4 RBP: ffffffff89807d18 R08: ffffffff8987a140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff8a7b87c0 R14: 0000000000000000 R15: 0000000000000000 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x904/0x943 init/main.c:784 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 workqueue events_power_efficient: flags=0x80 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256 refcnt=3 pending: fb_flashcursor, neigh_periodic_work pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256 refcnt=3 pending: check_lifetime, gc_worker workqueue rcu_gp: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 in-flight: 2826:srcu_invoke_callbacks workqueue mm_percpu_wq: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update workqueue dm_bufio_cache: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: work_fn workqueue ipv6_addrconf: flags=0x40008 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/1 refcnt=2 pending: addrconf_verify_work pool 2: cpus=1 node=0 flags=0x0 nice=0 hung=262s workers=3 idle: 3106 26