rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=262/1/0x4000000000000000 softirq=118324/118330 fqs=152 (t=10502 jiffies g=176273 q=278) rcu: rcu_preempt kthread starved for 10198 jiffies! g176273 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:29592 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0xec9/0x2280 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline] rcu_gp_kthread+0xb2c/0x1ca0 kernel/rcu/tree.c:2058 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 NMI backtrace for cpu 1 CPU: 1 PID: 14042 Comm: kworker/1:28 Not tainted 5.9.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: wg-crypt-wg0 wg_packet_tx_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x1e3/0x21e kernel/rcu/tree_stall.h:318 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline] check_cpu_stall kernel/rcu/tree_stall.h:625 [inline] rcu_pending kernel/rcu/tree.c:3637 [inline] rcu_sched_clock_irq.cold+0x4db/0xdfd kernel/rcu/tree.c:2519 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x147/0x5f0 arch/x86/kernel/apic/apic.c:1097 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:__list_add_valid+0x26/0xa0 lib/list_debug.c:23 Code: cc cc cc cc 48 b8 00 00 00 00 00 fc ff df 41 54 49 89 d4 55 48 89 fd 48 8d 7a 08 48 83 ec 08 48 89 fa 48 c1 ea 03 80 3c 02 00 <75> 50 49 8b 54 24 08 48 39 f2 0f 85 59 01 00 00 48 b8 00 00 00 00 RSP: 0000:ffffc9001c6475d0 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff88809da94b38 RCX: ffffffff86a316c6 RDX: 1ffff11013b52968 RSI: ffff88809da94b38 RDI: ffff88809da94b40 RBP: ffff888093a91310 R08: 0000000000000001 R09: 0000000000000003 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809da94b38 R13: dffffc0000000000 R14: ffff888093a91310 R15: ffff88809da94b38 __list_add include/linux/list.h:67 [inline] list_add_tail include/linux/list.h:100 [inline] list_move_tail include/linux/list.h:228 [inline] fq_codel_dequeue+0x864/0x1f50 net/sched/sch_fq_codel.c:299 dequeue_skb net/sched/sch_generic.c:263 [inline] qdisc_restart net/sched/sch_generic.c:366 [inline] __qdisc_run+0x1ac/0x1620 net/sched/sch_generic.c:384 __dev_xmit_skb net/core/dev.c:3789 [inline] __dev_queue_xmit+0x2628/0x2d70 net/core/dev.c:4106 neigh_hh_output include/net/neighbour.h:498 [inline] neigh_output include/net/neighbour.h:507 [inline] ip6_finish_output2+0x7e7/0x1780 net/ipv6/ip6_output.c:117 __ip6_finish_output net/ipv6/ip6_output.c:143 [inline] __ip6_finish_output+0x447/0xab0 net/ipv6/ip6_output.c:128 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip6_output+0x1db/0x520 net/ipv6/ip6_output.c:176 dst_output include/net/dst.h:443 [inline] ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:179 ip6tunnel_xmit include/net/ip6_tunnel.h:160 [inline] udp_tunnel6_xmit_skb+0x6a6/0xba0 net/ipv6/ip6_udp_tunnel.c:109 send6+0x4cd/0xbc0 drivers/net/wireguard/socket.c:152 wg_socket_send_skb_to_peer+0xf5/0x220 drivers/net/wireguard/socket.c:177 wg_packet_create_data_done drivers/net/wireguard/send.c:252 [inline] wg_packet_tx_worker+0x2f9/0x980 drivers/net/wireguard/send.c:280 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294