rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10500 ticks this GP) idle=ff6/1/0x4000000000000002 softirq=65921/65921 fqs=0 (t=10500 jiffies g=103865 q=1137) rcu: rcu_preempt kthread starved for 10500 jiffies! g103865 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt I29112 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3254 [inline] __schedule+0x755/0x1580 kernel/sched/core.c:3880 schedule+0xd9/0x260 kernel/sched/core.c:3947 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807 rcu_gp_fqs_loop kernel/rcu/tree.c:1611 [inline] rcu_gp_kthread+0x9b2/0x18c0 kernel/rcu/tree.c:1768 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: 2033 Comm: syz-executor.2 Not tainted 5.3.0-rc7+ #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+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:2736 [inline] rcu_sched_clock_irq.cold+0x4dd/0xc13 kernel/rcu/tree.c:2183 update_process_times+0x32/0x80 kernel/time/timer.c:1639 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 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:__sanitizer_cov_trace_pc+0x3b/0x50 kernel/kcov.c:107 Code: 88 8f 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b 8b 90 f0 12 00 00 83 fa 02 75 20 48 8b 88 f8 12 00 00 8b 80 f4 12 00 00 48 8b 11 <48> 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 RSP: 0018:ffff888067eae638 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: ffff888065e007b8 RCX: ffffc9000a37f000 RDX: 000000000003ffff RSI: ffffffff85c7e0db RDI: 0000000000000001 RBP: ffff888067eae638 R08: ffff8880a16aa200 R09: fffffbfff14e9555 R10: ffff8880a16aaba8 R11: ffff8880a16aa200 R12: dffffc0000000000 R13: ffff888065e004c0 R14: 0000000000000001 R15: 0000000000000000 __list_del_entry include/linux/list.h:134 [inline] __list_del_entry include/linux/list.h:129 [inline] list_move_tail include/linux/list.h:213 [inline] hhf_dequeue+0x5db/0xa20 net/sched/sch_hhf.c:439 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+0x16f1/0x3650 net/core/dev.c:3838 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902 br_dev_queue_push_xmit+0x3f3/0x5c0 net/bridge/br_forward.c:52 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] br_forward_finish+0xfa/0x400 net/bridge/br_forward.c:65 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] __br_forward+0x641/0xb00 net/bridge/br_forward.c:109 deliver_clone+0x61/0xc0 net/bridge/br_forward.c:125 maybe_deliver+0x2c7/0x390 net/bridge/br_forward.c:181 br_flood+0x13a/0x3d0 net/bridge/br_forward.c:223 br_dev_xmit+0xd33/0x15a0 net/bridge/br_device.c:84 __netdev_start_xmit include/linux/netdevice.h:4419 [inline] netdev_start_xmit include/linux/netdevice.h:4433 [inline] xmit_one net/core/dev.c:3280 [inline] dev_hard_start_xmit+0x1a3/0x9c0 net/core/dev.c:3296 __dev_queue_xmit+0x2b15/0x3650 net/core/dev.c:3869 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902 neigh_hh_output include/net/neighbour.h:500 [inline] neigh_output include/net/neighbour.h:509 [inline] ip_finish_output2+0x1726/0x2570 net/ipv4/ip_output.c:228 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x5fc/0xb90 net/ipv4/ip_output.c:290 ip_finish_output+0x38/0x1f0 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip_output+0x21f/0x640 net/ipv4/ip_output.c:432 dst_output include/net/dst.h:436 [inline] ip_local_out+0xbb/0x190 net/ipv4/ip_output.c:125 __ip_queue_xmit+0x86f/0x1bd0 net/ipv4/ip_output.c:532 sctp_v4_xmit+0x1a8/0x200 net/sctp/protocol.c:976 sctp_packet_transmit+0x1b9f/0x3650 net/sctp/output.c:629 sctp_packet_singleton net/sctp/outqueue.c:772 [inline] sctp_outq_flush_ctrl.constprop.0+0x73c/0xd30 net/sctp/outqueue.c:903 sctp_outq_flush+0xe8/0x2780 net/sctp/outqueue.c:1185 sctp_outq_uncork+0x6c/0x80 net/sctp/outqueue.c:757 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1781 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1184 [inline] sctp_do_sm+0x4b9/0x5170 net/sctp/sm_sideeffect.c:1155 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:73 __sctp_connect+0x835/0xcd0 net/sctp/socket.c:1212 __sctp_setsockopt_connectx+0x137/0x1a0 net/sctp/socket.c:1321 sctp_setsockopt_connectx net/sctp/socket.c:1353 [inline] sctp_setsockopt net/sctp/socket.c:4653 [inline] sctp_setsockopt+0x1279/0x7180 net/sctp/socket.c:4610 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3142 __sys_setsockopt+0x261/0x4c0 net/socket.c:2084 __do_sys_setsockopt net/socket.c:2100 [inline] __se_sys_setsockopt net/socket.c:2097 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2097 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4598e9 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f103cf5dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00000000004598e9 RDX: 000000000000006e RSI: 0000000000000084 RDI: 000000000000000a RBP: 000000000075bf20 R08: 0000000000000010 R09: 0000000000000000 R10: 0000000020961fe4 R11: 0000000000000246 R12: 00007f103cf5e6d4 R13: 00000000004cfad0 R14: 00000000004de418 R15: 00000000ffffffff