syzbot

INFO: rcu_preempt self-detected stall on CPU
	1-...: (12499 ticks this GP) idle=179/140000000000001/0 softirq=9232/9233 fqs=12494 
	 (t=12500 jiffies g=2041 c=2040 q=3013)
Task dump for CPU 1:
syz-executor3   R  running task    27032  8597   4050 0x0000000c
 0000000000000fd2 43cad53c85dfbd88 ffff8801db307c10 ffffffff811cb818
 0000000000000002 0000000000000000 ffff8801db31f4c0 0000000000000001
 ffffffff842beec0 ffffffff842bef44 dffffc0000000000 ffff8801db307c30
Call Trace:
 <IRQ>  [<ffffffff811cb818>] sched_show_task+0x208/0x3b0 kernel/sched/core.c:5083
 [<ffffffff811d3011>] dump_cpu_task+0x71/0x90 kernel/sched/core.c:9027
 [<ffffffff81289fbb>] rcu_dump_cpu_stacks+0x1bb/0x2f0 kernel/rcu/tree.c:1233
 [<ffffffff81297199>] print_cpu_stall kernel/rcu/tree.c:1340 [inline]
 [<ffffffff81297199>] check_cpu_stall kernel/rcu/tree.c:1404 [inline]
 [<ffffffff81297199>] __rcu_pending kernel/rcu/tree.c:3892 [inline]
 [<ffffffff81297199>] rcu_pending kernel/rcu/tree.c:3956 [inline]
 [<ffffffff81297199>] rcu_check_callbacks+0x909/0x1fe0 kernel/rcu/tree.c:2796
 [<ffffffff812ab0da>] update_process_times+0x3a/0x70 kernel/time/timer.c:1427
 [<ffffffff812d5795>] tick_sched_handle.isra.16+0x55/0xf0 kernel/time/tick-sched.c:151
 [<ffffffff812d70b2>] tick_sched_timer+0x72/0x120 kernel/time/tick-sched.c:1097
 [<ffffffff812ad8d6>] __run_hrtimer kernel/time/hrtimer.c:1255 [inline]
 [<ffffffff812ad8d6>] __hrtimer_run_queues+0x306/0xfe0 kernel/time/hrtimer.c:1319
 [<ffffffff812afdb6>] hrtimer_interrupt+0x1a6/0x440 kernel/time/hrtimer.c:1353
 [<ffffffff810b0cda>] local_apic_timer_interrupt+0x6a/0xb0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff83776b36>] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff83775a90>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:737
 <EOI>  [<ffffffff833d5414>] ? _decode_session6+0x484/0x13d0 net/ipv6/xfrm6_policy.c:149
 [<ffffffff832a4ff3>] __xfrm_decode_session+0x63/0x100 net/xfrm/xfrm_policy.c:2397
 [<ffffffff832ad5c5>] __xfrm_policy_check+0x135/0x1a40 net/xfrm/xfrm_policy.c:2434
 [<ffffffff8337344d>] __xfrm_policy_check2 include/net/xfrm.h:1067 [inline]
 [<ffffffff8337344d>] xfrm_policy_check include/net/xfrm.h:1076 [inline]
 [<ffffffff8337344d>] xfrm6_policy_check include/net/xfrm.h:1086 [inline]
 [<ffffffff8337344d>] udpv6_queue_rcv_skb+0x65d/0x1510 net/ipv6/udp.c:634
 [<ffffffff82df8606>] sk_backlog_rcv include/net/sock.h:871 [inline]
 [<ffffffff82df8606>] __release_sock net/core/sock.c:2023 [inline]
 [<ffffffff82df8606>] release_sock+0x176/0x510 net/core/sock.c:2473
 [<ffffffff831a2664>] udp_sendmsg+0x15c4/0x1c30 net/ipv4/udp.c:1105
 [<ffffffff83371354>] udpv6_sendmsg+0x1434/0x2500 net/ipv6/udp.c:1178
 [<ffffffff831d6c0c>] inet_sendmsg+0x2bc/0x4c0 net/ipv4/af_inet.c:755
 [<ffffffff82deb3ba>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82deb3ba>] sock_sendmsg+0xca/0x110 net/socket.c:635
 [<ffffffff82dec308>] SYSC_sendto+0x2c8/0x340 net/socket.c:1665
 [<ffffffff82dee800>] SyS_sendto+0x40/0x50 net/socket.c:1633
 [<ffffffff83773edf>] entry_SYSCALL_64_fastpath+0x1c/0x98