syzbot

INFO: rcu_preempt self-detected stall on CPU
	0-...: (1 GPs behind) idle=22b/140000000000001/0 softirq=9324/9332 fqs=12497 
	 (t=12500 jiffies g=996 c=995 q=801)
Task dump for CPU 0:
syz-executor994 R  running task    28432  3975   3938 0x0000000c
 0000000000000f62 90a48b52b8005eeb ffff8801db206fe0 ffffffff8140c8fc
 ffff8801db21f4c0 0000000000000000 dffffc0000000000 ffffffff844bef00
 ffffffff844bef84 ffff8801db207000 ffffffff8140cb87 ffffffff844bef48
Call Trace:
 <IRQ>  [<ffffffff8140c8fc>] sched_show_task+0x2cb/0x2d6 kernel/sched/core.c:5089
 [<ffffffff8140cb87>] dump_cpu_task+0x79/0x7e kernel/sched/core.c:9046
 [<ffffffff8141704d>] rcu_dump_cpu_stacks+0x150/0x164 kernel/rcu/tree.c:1233
 [<ffffffff81417c4a>] print_cpu_stall kernel/rcu/tree.c:1340 [inline]
 [<ffffffff81417c4a>] check_cpu_stall kernel/rcu/tree.c:1404 [inline]
 [<ffffffff81417c4a>] __rcu_pending kernel/rcu/tree.c:3892 [inline]
 [<ffffffff81417c4a>] rcu_pending kernel/rcu/tree.c:3956 [inline]
 [<ffffffff81417c4a>] rcu_check_callbacks.cold.75+0x5c3/0xd20 kernel/rcu/tree.c:2796
 [<ffffffff8129a7da>] update_process_times+0x3a/0x70 kernel/time/timer.c:1427
 [<ffffffff812c5195>] tick_sched_handle.isra.15+0x55/0xf0 kernel/time/tick-sched.c:151
 [<ffffffff812c5822>] tick_sched_timer+0x72/0x120 kernel/time/tick-sched.c:1097
 [<ffffffff8129dd4d>] __run_hrtimer kernel/time/hrtimer.c:1261 [inline]
 [<ffffffff8129dd4d>] __hrtimer_run_queues+0x3ad/0x1000 kernel/time/hrtimer.c:1325
 [<ffffffff8129f4c1>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1359
 [<ffffffff810ad284>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff838c534c>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff838c4290>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 [<ffffffff834fb7a2>] _decode_session6+0xb72/0x14d0 net/ipv6/xfrm6_policy.c:160
 [<ffffffff833c9b39>] __xfrm_decode_session+0x69/0x100 net/xfrm/xfrm_policy.c:2403
 [<ffffffff834a3d9e>] xfrm_decode_session_reverse include/net/xfrm.h:1114 [inline]
 [<ffffffff834a3d9e>] icmpv6_route_lookup+0x2ce/0x440 net/ipv6/icmp.c:362
 [<ffffffff834a5b99>] icmp6_send+0xee9/0x1b80 net/ipv6/icmp.c:507
 [<ffffffff8355b491>] icmpv6_send+0xb1/0x1b0 net/ipv6/ip6_icmp.c:42
 [<ffffffff8346309d>] ip6_pkt_drop+0x16d/0x430 net/ipv6/route.c:2472
 [<ffffffff8346337c>] ip6_pkt_discard+0x1c/0x20 net/ipv6/route.c:2479
 [<ffffffff834360bd>] dst_input include/net/dst.h:504 [inline]
 [<ffffffff834360bd>] ip6_rcv_finish+0x13d/0x640 net/ipv6/ip6_input.c:62
 [<ffffffff83438bdb>] NF_HOOK_THRESH include/linux/netfilter.h:226 [inline]
 [<ffffffff83438bdb>] NF_HOOK include/linux/netfilter.h:249 [inline]
 [<ffffffff83438bdb>] ipv6_rcv+0x10cb/0x1cd0 net/ipv6/ip6_input.c:186
 [<ffffffff82f7eb06>] __netif_receive_skb_core+0x12d6/0x2940 net/core/dev.c:4019
 [<ffffffff82f801cb>] __netif_receive_skb+0x5b/0x1b0 net/core/dev.c:4054
 [<ffffffff82f84756>] process_backlog+0x216/0x6a0 net/core/dev.c:4647
 [<ffffffff82f81592>] napi_poll net/core/dev.c:4885 [inline]
 [<ffffffff82f81592>] net_rx_action+0x3a2/0xdb0 net/core/dev.c:4950
 [<ffffffff838c5bec>] __do_softirq+0x22c/0xa1a kernel/softirq.c:273
 [<ffffffff838c399c>] do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:929
 <EOI>  [<ffffffff8113d9d4>] do_softirq.part.16+0x54/0x60 kernel/softirq.c:317
 [<ffffffff8113f6c9>] do_softirq+0x19/0x20 kernel/softirq.c:320
 [<ffffffff82f7caac>] netif_rx_ni+0xec/0x3a0 net/core/dev.c:3653
 [<ffffffff82753187>] tun_get_user+0xbe7/0x2410 drivers/net/tun.c:1264
 [<ffffffff82754bc5>] tun_chr_write_iter+0xd5/0x190 drivers/net/tun.c:1283
 [<ffffffff8151ce0d>] new_sync_write fs/read_write.c:478 [inline]
 [<ffffffff8151ce0d>] __vfs_write+0x30d/0x3f0 fs/read_write.c:491
 [<ffffffff8151e9f1>] vfs_write+0x191/0x4e0 fs/read_write.c:538
 [<ffffffff81520ff9>] SYSC_write fs/read_write.c:585 [inline]
 [<ffffffff81520ff9>] SyS_write+0xd9/0x1c0 fs/read_write.c:577
 [<ffffffff838c2725>] entry_SYSCALL_64_fastpath+0x22/0x9e