rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=54a/1/0x4000000000000000 softirq=256951/256969 fqs=50 (t=10502 jiffies g=480925 q=121) rcu: rcu_preempt kthread starved for 10401 jiffies! g480925 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:R running task stack:28800 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4339 [inline] __schedule+0x916/0x23e0 kernel/sched/core.c:5147 schedule+0xcf/0x270 kernel/sched/core.c:5226 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1892 rcu_gp_fqs_loop kernel/rcu/tree.c:2004 [inline] rcu_gp_kthread+0xd07/0x2300 kernel/rcu/tree.c:2177 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10056 Comm: kworker/1:4 Not tainted 5.13.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: wg-crypt-wg0 wg_packet_tx_worker RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:90 [inline] RIP: 0010:kvm_wait arch/x86/kernel/kvm.c:888 [inline] RIP: 0010:kvm_wait+0xb2/0x100 arch/x86/kernel/kvm.c:871 Code: 89 74 24 0c 48 89 3c 24 e8 6b 2b 48 00 8b 74 24 0c 48 8b 3c 24 eb 82 e8 8c 30 48 00 e9 07 00 00 00 0f 00 2d 90 10 36 08 fb f4 98 e9 07 00 00 00 0f 00 2d 80 10 36 08 f4 eb bf 89 74 24 0c 48 RSP: 0000:ffffc90019bcf5f0 EFLAGS: 00000212 RAX: 00000000000432e0 RBX: 0000000000000000 RCX: 1ffffffff204f1aa RDX: 0000000000000000 RSI: 0000000000000803 RDI: 0000000000000000 RBP: ffff8880879630f0 R08: 0000000000000001 R09: ffffffff9022597f R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: ffffed1010f2c61e R14: 0000000000000001 R15: ffff8880b9d36000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000050 CR3: 000000005d13b000 CR4: 00000000001506e0 Call Trace: pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x8b8/0xb40 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:113 spin_lock include/linux/spinlock.h:354 [inline] __dev_xmit_skb net/core/dev.c:3873 [inline] __dev_queue_xmit+0x1796/0x2e30 net/core/dev.c:4213 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0x911/0x1700 net/ipv6/ip6_output.c:117 __ip6_finish_output net/ipv6/ip6_output.c:182 [inline] __ip6_finish_output+0x4c1/0xe10 net/ipv6/ip6_output.c:161 ip6_finish_output+0x35/0x200 net/ipv6/ip6_output.c:192 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:215 dst_output include/net/dst.h:448 [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+0x4da/0xcb0 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:251 [inline] wg_packet_tx_worker+0x1a7/0x710 drivers/net/wireguard/send.c:276 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 NMI backtrace for cpu 0 CPU: 0 PID: 10558 Comm: syz-executor.4 Not tainted 5.13.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:341 print_cpu_stall kernel/rcu/tree_stall.h:624 [inline] check_cpu_stall kernel/rcu/tree_stall.h:699 [inline] rcu_pending kernel/rcu/tree.c:3911 [inline] rcu_sched_clock_irq.cold+0x3f1/0x74b kernel/rcu/tree.c:2649 update_process_times+0x16d/0x200 kernel/time/timer.c:1796 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1373 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647 RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:197 Code: 81 e1 00 01 00 00 65 48 8b 14 25 00 f0 01 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 3c 15 00 00 85 c0 74 2b 8b 82 18 15 00 00 <83> f8 02 75 20 48 8b 8a 20 15 00 00 8b 92 1c 15 00 00 48 8b 01 48 RSP: 0018:ffffc9001b1dec08 EFLAGS: 00000246 RAX: 0000000000000002 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: ffff8880143f3880 RSI: ffffffff873c534f RDI: ffff888062013d08 RBP: ffff8880879632d8 R08: 0000000000000000 R09: ffffffff90225957 R10: ffffffff873c53a3 R11: 0000000000000000 R12: ffff888062013cc0 R13: ffff888062013b40 R14: ffff8880879632d0 R15: ffff888087963000 fq_dequeue+0x49f/0x2040 net/sched/sch_fq.c:549 dequeue_skb net/sched/sch_generic.c:263 [inline] qdisc_restart net/sched/sch_generic.c:366 [inline] __qdisc_run+0x1ae/0x15f0 net/sched/sch_generic.c:384 __dev_xmit_skb net/core/dev.c:3904 [inline] __dev_queue_xmit+0x19d5/0x2e30 net/core/dev.c:4213 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0x911/0x1700 net/ipv6/ip6_output.c:117 __ip6_finish_output net/ipv6/ip6_output.c:182 [inline] __ip6_finish_output+0x4c1/0xe10 net/ipv6/ip6_output.c:161 ip6_finish_output+0x35/0x200 net/ipv6/ip6_output.c:192 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:215 dst_output include/net/dst.h:448 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] NF_HOOK include/linux/netfilter.h:295 [inline] ip6_xmit+0x1277/0x1ea0 net/ipv6/ip6_output.c:320 sctp_v6_xmit+0xc5c/0x1040 net/sctp/ipv6.c:223 sctp_packet_transmit+0x1c03/0x2f60 net/sctp/output.c:620 sctp_packet_singleton net/sctp/outqueue.c:773 [inline] sctp_outq_flush_ctrl.constprop.0+0x6d3/0xc40 net/sctp/outqueue.c:904 sctp_outq_flush net/sctp/outqueue.c:1193 [inline] sctp_outq_uncork+0x10b/0x200 net/sctp/outqueue.c:758 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1775 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1163 [inline] sctp_do_sm+0x74e/0x4e90 net/sctp/sm_sideeffect.c:1134 sctp_primitive_ASSOCIATE+0x98/0xc0 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0xb8b/0x2180 net/sctp/socket.c:1837 sctp_sendmsg+0x103b/0x1d30 net/sctp/socket.c:2027 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 __sys_sendto+0x21c/0x320 net/socket.c:1977 __do_sys_sendto net/socket.c:1989 [inline] __se_sys_sendto net/socket.c:1985 [inline] __ia32_sys_sendto+0xdb/0x1b0 net/socket.c:1985 do_syscall_32_irqs_on arch/x86/entry/common.c:78 [inline] __do_fast_syscall_32+0x67/0xe0 arch/x86/entry/common.c:143 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:168 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7f43549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f553d5fc EFLAGS: 00000296 ORIG_RAX: 0000000000000171 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020847fff RDX: 00000000000118a8 RSI: 0000000000000000 RDI: 000000002005ffe4 RBP: 000000000000001c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000