rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=210297, q=21) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295091844-4295081342), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g210297 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28720 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4700 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5957 schedule+0xd3/0x270 kernel/sched/core.c:6036 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1879 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1963 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2136 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 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: 10409 Comm: kworker/0:5 Not tainted 5.14.0-rc2-next-20210721-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:should_restart_cycle net/sched/sch_taprio.c:661 [inline] RIP: 0010:advance_sched+0x1df/0x9a0 net/sched/sch_taprio.c:734 Code: 00 e8 a5 5e 2a fa 48 8d 45 10 4c 89 ea 48 89 44 24 20 48 c1 ea 03 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 0f 85 00 07 00 00 <48> 8d 7d 28 4d 8b 65 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 RSP: 0018:ffffc90000007348 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff88802c7e3b40 RCX: 0000000000000100 RDX: 1ffff11004fbd080 RSI: ffffffff874b62fb RDI: 0000000000000003 RBP: ffff8880293a5f80 R08: 173989f6ae7313ed R09: 0000000000000003 R10: ffffffff874b62ed R11: 0000000000000000 R12: 0000000000000000 R13: ffff888027de8400 R14: 173989f6ae7313ed R15: ffffffff874b6140 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fd24000 CR3: 00000000a456c000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x609/0xe50 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+0x146/0x530 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__find_rr_leaf+0x279/0xd20 net/ipv6/route.c:790 Code: 84 c0 0f 85 67 09 00 00 45 88 65 14 e8 50 62 a1 f9 48 8d 7b 08 48 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 93 08 00 00 48 8b 5b 08 f2 9f 8c f9 31 ff 41 89 c4 89 c6 e8 66 69 a1 f9 45 85 e4 0f 84 RSP: 0018:ffffc90000007640 EFLAGS: 00000246 RAX: 1ffff1100e248ac1 RBX: ffff888071246a00 RCX: 0000000000000100 RDX: ffff88802b391c80 RSI: ffffffff87d45f50 RDI: ffff888071245608 RBP: dffffc0000000000 R08: 00000000fffffffd R09: 0000000000000000 R10: ffffffff87d45e7b R11: 0000000000000000 R12: ffff888071245654 R13: ffffc90000007928 R14: 0000000000000000 R15: ffff8880712456a0 find_rr_leaf net/ipv6/route.c:846 [inline] rt6_select net/ipv6/route.c:890 [inline] fib6_table_lookup+0x649/0xa20 net/ipv6/route.c:2174 ip6_pol_route+0x1c5/0x11d0 net/ipv6/route.c:2210 pol_lookup_func include/net/ip6_fib.h:579 [inline] fib6_rule_lookup+0x111/0x6f0 net/ipv6/fib6_rules.c:115 ip6_route_input_lookup net/ipv6/route.c:2280 [inline] ip6_route_input+0x63c/0xb30 net/ipv6/route.c:2576 ip6_rcv_finish_core.constprop.0.isra.0+0x168/0x570 net/ipv6/ip6_input.c:63 ip6_rcv_finish net/ipv6/ip6_input.c:74 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x229/0x3c0 net/ipv6/ip6_input.c:297 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5520 __netif_receive_skb+0x24/0x1b0 net/core/dev.c:5634 process_backlog+0x2a5/0x6c0 net/core/dev.c:6495 __napi_poll+0xaf/0x440 net/core/dev.c:7050 napi_poll net/core/dev.c:7117 [inline] net_rx_action+0x801/0xb40 net/core/dev.c:7204 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 do_softirq.part.0+0xde/0x130 kernel/softirq.c:459 do_softirq kernel/softirq.c:451 [inline] __local_bh_enable_ip+0x102/0x120 kernel/softirq.c:383 local_bh_enable include/linux/bottom_half.h:32 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:757 [inline] ip6_finish_output2+0x7b2/0x19d0 net/ipv6/ip6_output.c:146 __ip6_finish_output net/ipv6/ip6_output.c:210 [inline] __ip6_finish_output+0x4c1/0x1050 net/ipv6/ip6_output.c:189 ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:220 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:243 dst_output include/net/dst.h:448 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] mld_sendpack+0x8d4/0xdc0 net/ipv6/mcast.c:1823 mld_send_initial_cr.part.0+0x194/0x230 net/ipv6/mcast.c:2242 mld_send_initial_cr net/ipv6/mcast.c:1227 [inline] ipv6_mc_dad_complete+0x1d0/0x690 net/ipv6/mcast.c:2250 addrconf_dad_completed+0xa20/0xd60 net/ipv6/addrconf.c:4175 addrconf_dad_work+0x79f/0x1340 net/ipv6/addrconf.c:4105 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295