rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=cca/1/0x4000000000000000 softirq=148392/148394 fqs=306 (t=10500 jiffies g=274073 q=1053) rcu: rcu_preempt kthread timer wakeup didn't happen for 9851 jiffies! g274073 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=113602 rcu: rcu_preempt kthread starved for 9852 jiffies! g274073 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:28160 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3081 Comm: kworker/0:9 Not tainted 5.13.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: wg-crypt-wg1 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 5b 31 48 00 8b 74 24 0c 48 8b 3c 24 eb 82 e8 7c 36 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: 0018:ffffc90017ad75f0 EFLAGS: 00000202 RAX: 0000000000100b54 RBX: 0000000000000000 RCX: 1ffffffff204f212 RDX: 0000000000000000 RSI: 0000000000000803 RDI: 0000000000000000 RBP: ffff8880a3af70f0 R08: 0000000000000001 R09: ffffffff9022697f R10: 0000000000000001 R11: 0000000000000012 R12: 0000000000000000 R13: ffffed101475ee1e R14: 0000000000000001 R15: ffff8880b9c36400 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000237e848 CR3: 000000000bc8e000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 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:3874 [inline] __dev_queue_xmit+0x178e/0x3130 net/core/dev.c:4214 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip_finish_output2+0xeec/0x21f0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x396/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x35/0x200 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:290 [inline] ip_output+0x196/0x310 net/ipv4/ip_output.c:432 dst_output include/net/dst.h:448 [inline] ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:126 iptunnel_xmit+0x5a3/0x9c0 net/ipv4/ip_tunnel_core.c:82 send4+0x454/0xe30 drivers/net/wireguard/socket.c:85 wg_socket_send_skb_to_peer+0x192/0x220 drivers/net/wireguard/socket.c:174 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:2276 worker_thread+0x64c/0x1120 kernel/workqueue.c:2422 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 NMI backtrace for cpu 1 CPU: 1 PID: 26704 Comm: kworker/1:13 Not tainted 5.13.0-rc3-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: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:lock_is_held_type+0xfd/0x140 kernel/locking/lockdep.c:5560 Code: 00 00 b8 ff ff ff ff 65 0f c1 05 0e 8b eb 76 83 f8 01 75 29 9c 58 f6 c4 02 75 3d 48 f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 <44> 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 45 31 ed eb b9 0f 0b 48 RSP: 0018:ffffc90002b77568 EFLAGS: 00000282 RAX: 0000000000000046 RBX: 0000000000000008 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000803 RDI: 0000000000000000 RBP: ffffffff8bf79260 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8705f6ca R11: 0000000000000000 R12: ffff88803276b880 R13: 0000000000000000 R14: 00000000ffffffff R15: ffff88803276c390 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_kfree_skb include/trace/events/skb.h:15 [inline] kfree_skb net/core/skbuff.c:757 [inline] kfree_skb+0x34e/0x3f0 net/core/skbuff.c:752 kfree_skb_list+0x3f/0x60 net/core/skbuff.c:767 netem_dequeue+0x80a/0xe20 net/sched/sch_netem.c:724 dequeue_skb net/sched/sch_generic.c:286 [inline] qdisc_restart net/sched/sch_generic.c:391 [inline] __qdisc_run+0x1ae/0x1680 net/sched/sch_generic.c:409 __dev_xmit_skb net/core/dev.c:3905 [inline] __dev_queue_xmit+0x19d5/0x3130 net/core/dev.c:4214 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:2276 worker_thread+0x64c/0x1120 kernel/workqueue.c:2422 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294