rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=da6/1/0x4000000000000002 softirq=9961/9962 fqs=13 (t=10500 jiffies g=8573 q=7) rcu: rcu_preempt kthread starved for 10474 jiffies! g8573 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt I29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3265 [inline] __schedule+0x76e/0x17a0 kernel/sched/core.c:3937 schedule+0xd9/0x260 kernel/sched/core.c:4004 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1893 rcu_gp_fqs_loop kernel/rcu/tree.c:1639 [inline] rcu_gp_kthread+0x9b2/0x18d0 kernel/rcu/tree.c:1799 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 1 CPU: 1 PID: 9121 Comm: syz-executor716 Not tainted 5.3.0-rc6-next-20190830 #75 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 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2795 [inline] rcu_sched_clock_irq.cold+0x4fd/0xc12 kernel/rcu/tree.c:2244 update_process_times+0x2d/0x70 kernel/time/timer.c:1724 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1299 __run_hrtimer kernel/time/hrtimer.c:1504 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1566 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1628 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1106 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1131 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 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:214 [inline] RIP: 0010:hhf_dequeue+0x67d/0xa20 net/sched/sch_hhf.c:439 Code: 5b 03 00 00 4d 8b bd 98 03 00 00 48 89 df 48 8b 55 c8 4c 89 fe e8 43 55 77 fd 31 ff 89 c6 88 45 b0 e8 d7 e7 a6 fb 0f b6 75 b0 <40> 84 f6 0f 84 c6 f9 ff ff e8 85 e6 a6 fb 4c 89 f0 48 c1 e8 03 42 RSP: 0018:ffff8880ae908b48 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000302 RBX: ffff88809b8d02f8 RCX: ffffffff85cb6f79 RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffff8880ae908b98 R08: ffff8880979d4580 R09: fffffbfff14ed341 R10: ffff8880979d4f10 R11: ffff8880979d4580 R12: dffffc0000000000 R13: ffff88809b8d0000 R14: ffff88809b8d0398 R15: ffff88809b8d0390 dequeue_skb net/sched/sch_generic.c:258 [inline] qdisc_restart net/sched/sch_generic.c:361 [inline] __qdisc_run+0x1e7/0x19d0 net/sched/sch_generic.c:379 __dev_xmit_skb net/core/dev.c:3533 [inline] __dev_queue_xmit+0x16f1/0x37c0 net/core/dev.c:3838 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902 br_dev_queue_push_xmit+0x3f3/0x5e0 net/bridge/br_forward.c:52 br_nf_dev_queue_xmit+0x34e/0x14b0 net/bridge/br_netfilter_hooks.c:796 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] br_nf_post_routing+0x1502/0x1d30 net/bridge/br_netfilter_hooks.c:844 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:260 [inline] NF_HOOK include/linux/netfilter.h:303 [inline] br_forward_finish+0x215/0x400 net/bridge/br_forward.c:65 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015 br_nf_forward_finish+0x66c/0xa90 net/bridge/br_netfilter_hooks.c:560 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] br_nf_forward_ip net/bridge/br_netfilter_hooks.c:630 [inline] br_nf_forward_ip+0xc74/0x21e0 net/bridge/br_netfilter_hooks.c:571 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:260 [inline] NF_HOOK include/linux/netfilter.h:303 [inline] __br_forward+0x393/0xb00 net/bridge/br_forward.c:109 deliver_clone+0x61/0xc0 net/bridge/br_forward.c:125 br_flood+0x325/0x3d0 net/bridge/br_forward.c:232 br_handle_frame_finish+0xb46/0x1670 net/bridge/br_input.c:162 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015 br_nf_pre_routing_finish_ipv6+0x6fa/0xdb0 net/bridge/br_netfilter_ipv6.c:206 NF_HOOK include/linux/netfilter.h:305 [inline] br_nf_pre_routing_ipv6+0x456/0x840 net/bridge/br_netfilter_ipv6.c:236 br_nf_pre_routing+0x1743/0x2360 net/bridge/br_netfilter_hooks.c:501 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_bridge_pre net/bridge/br_input.c:223 [inline] br_handle_frame+0x806/0x1340 net/bridge/br_input.c:348 __netif_receive_skb_core+0xfc1/0x3060 net/core/dev.c:4907 __netif_receive_skb_one_core+0xa8/0x1a0 net/core/dev.c:5004 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5120 process_backlog+0x206/0x750 net/core/dev.c:5951 napi_poll net/core/dev.c:6388 [inline] net_rx_action+0x50a/0x10d0 net/core/dev.c:6456 __do_softirq+0x262/0x98c kernel/softirq.c:292 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:337 do_softirq kernel/softirq.c:329 [inline] __local_bh_enable_ip+0x211/0x270 kernel/softirq.c:189 local_bh_enable include/linux/bottom_half.h:32 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:2014 [inline] nf_ct_iterate_cleanup+0x217/0x4e0 net/netfilter/nf_conntrack_core.c:2037 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2122 [inline] nf_ct_iterate_cleanup_net+0x133/0x190 net/netfilter/nf_conntrack_core.c:2107 masq_device_event+0xb5/0xe0 net/netfilter/nf_nat_masquerade.c:88 notifier_call_chain+0xc2/0x230 kernel/notifier.c:95 __raw_notifier_call_chain kernel/notifier.c:396 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1749 call_netdevice_notifiers_extack net/core/dev.c:1761 [inline] call_netdevice_notifiers net/core/dev.c:1775 [inline] dev_close_many+0x33f/0x6f0 net/core/dev.c:1518 rollback_registered_many+0x43b/0xfc0 net/core/dev.c:8227 rollback_registered+0x109/0x1d0 net/core/dev.c:8292 unregister_netdevice_queue net/core/dev.c:9339 [inline] unregister_netdevice_queue+0x1ee/0x2c0 net/core/dev.c:9332 unregister_netdevice include/linux/netdevice.h:2643 [inline] __tun_detach+0xd8a/0x1040 drivers/net/tun.c:723 tun_detach drivers/net/tun.c:740 [inline] tun_chr_close+0xe0/0x180 drivers/net/tun.c:3442 __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:879 do_group_exit+0x135/0x360 kernel/exit.c:983 __do_sys_exit_group kernel/exit.c:994 [inline] __se_sys_exit_group kernel/exit.c:992 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:992 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440c68 Code: Bad RIP value. RSP: 002b:00007ffe5ac9bd08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000440c68 RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001 RBP: 00000000004c7110 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 00000000bb1414ac R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d9600 R14: 0000000000000000 R15: 0000000000000000