IPVS: ftp: loaded support on port[0] = 21 rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (1 GPs behind) idle=ff6/1/0x4000000000000004 softirq=43846/43848 fqs=5228 rcu: (t=10500 jiffies g=56429 q=3162) NMI backtrace for cpu 1 CPU: 1 PID: 7897 Comm: kworker/u4:5 Not tainted 4.19.72 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x189/0x1d5 kernel/rcu/tree.c:1340 print_cpu_stall kernel/rcu/tree.c:1478 [inline] check_cpu_stall kernel/rcu/tree.c:1550 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold+0x5e3/0xd90 kernel/rcu/tree.c:2682 update_process_times+0x32/0x80 kernel/time/timer.c:1636 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:164 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1274 __run_hrtimer kernel/time/hrtimer.c:1398 [inline] __hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1460 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1518 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline] smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1092 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:__list_add include/linux/list.h:60 [inline] RIP: 0010:list_add_tail include/linux/list.h:93 [inline] RIP: 0010:list_move_tail include/linux/list.h:183 [inline] RIP: 0010:hhf_dequeue+0x659/0xa00 net/sched/sch_hhf.c:438 Code: e8 03 42 80 3c 20 00 0f 85 4e 03 00 00 4d 8b bd 58 03 00 00 48 89 df 48 8b 55 c8 4c 89 fe e8 0e 46 97 fd 31 ff 89 c6 88 45 b0 42 d9 dc fb 0f b6 75 b0 40 84 f6 0f 84 e1 f9 ff ff e8 f0 d7 dc RSP: 0018:ffff8880ae906e88 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: ffff8880a4ed9978 RCX: ffffffff858e7de6 RDX: ffff8880a4ed9a10 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8880ae906ed8 R08: ffff88809e530500 R09: 000000000000000c R10: ffff88809e530f60 R11: 00000000b23cdb25 R12: dffffc0000000000 R13: ffff8880a4ed96c0 R14: ffff8880a4ed9a18 R15: ffff8880a4ed9a10 dequeue_skb net/sched/sch_generic.c:277 [inline] qdisc_restart net/sched/sch_generic.c:380 [inline] __qdisc_run+0x1e7/0x1960 net/sched/sch_generic.c:398 __dev_xmit_skb net/core/dev.c:3501 [inline] __dev_queue_xmit+0x165c/0x2fe0 net/core/dev.c:3811 dev_queue_xmit+0x18/0x20 net/core/dev.c:3876 br_dev_queue_push_xmit+0x405/0x5d0 net/bridge/br_forward.c:56 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] br_forward_finish+0xfa/0x400 net/bridge/br_forward.c:69 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] __br_forward+0x647/0xb30 net/bridge/br_forward.c:113 deliver_clone+0x61/0xc0 net/bridge/br_forward.c:129 maybe_deliver net/bridge/br_forward.c:184 [inline] maybe_deliver net/bridge/br_forward.c:172 [inline] br_flood+0x4da/0x710 net/bridge/br_forward.c:226 br_dev_xmit+0xeeb/0x1490 net/bridge/br_device.c:103 __netdev_start_xmit include/linux/netdevice.h:4303 [inline] netdev_start_xmit include/linux/netdevice.h:4312 [inline] xmit_one net/core/dev.c:3257 [inline] dev_hard_start_xmit+0x1a5/0x980 net/core/dev.c:3273 __dev_queue_xmit+0x2704/0x2fe0 net/core/dev.c:3843 dev_queue_xmit+0x18/0x20 net/core/dev.c:3876 neigh_resolve_output net/core/neighbour.c:1369 [inline] neigh_resolve_output+0x5b7/0x980 net/core/neighbour.c:1349 neigh_output include/net/neighbour.h:501 [inline] ip6_finish_output2+0xb7f/0x2550 net/ipv6/ip6_output.c:120 ip6_finish_output+0x574/0xbe0 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x235/0x7c0 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:447 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] ndisc_send_skb+0xf3b/0x1460 net/ipv6/ndisc.c:491 ndisc_send_rs+0x134/0x6d0 net/ipv6/ndisc.c:685 addrconf_rs_timer+0x30f/0x680 net/ipv6/addrconf.c:3821 call_timer_fn+0x18d/0x720 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers kernel/time/timer.c:1682 [inline] __run_timers kernel/time/timer.c:1650 [inline] run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1695 __do_softirq+0x25c/0x921 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1094 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_release+0x47a/0xa30 kernel/locking/lockdep.c:3922 Code: 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 a7 03 00 00 48 83 3d ad ba 1f 07 00 0f 84 65 02 00 00 48 8b bd 68 ff ff ff 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 c7 04 03 00 00 00 RSP: 0018:ffff88807b58f930 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff10e48c1 RBX: 1ffff1100f6b1f2c RCX: 1ffff11013ca61ae RDX: dffffc0000000000 RSI: 0000000000000006 RDI: 0000000000000282 RBP: ffff88807b58f9e8 R08: ffff88809e530500 R09: 0000000000000005 R10: ffff88807b58fab8 R11: ffffc90001999307 R12: ffff88809e530500 R13: ffffffff836615a8 R14: 0000000000000003 R15: ffff88807b58f9c0 __mutex_unlock_slowpath+0x8e/0x6b0 kernel/locking/mutex.c:1197 mutex_unlock+0xd/0x10 kernel/locking/mutex.c:713 commit_echoes+0x138/0x1c0 drivers/tty/n_tty.c:787 n_tty_receive_char_fast drivers/tty/n_tty.c:1447 [inline] n_tty_receive_buf_fast drivers/tty/n_tty.c:1607 [inline] __receive_buf drivers/tty/n_tty.c:1642 [inline] n_tty_receive_buf_common+0x1d4c/0x28e0 drivers/tty/n_tty.c:1740 n_tty_receive_buf2+0x34/0x40 drivers/tty/n_tty.c:1775 tty_ldisc_receive_buf+0xad/0x1c0 drivers/tty/tty_buffer.c:456 tty_port_default_receive_buf+0x7d/0xb0 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:476 [inline] flush_to_ldisc+0x222/0x390 drivers/tty/tty_buffer.c:528 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415