rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10501 ticks this GP) idle=8f6/1/0x4000000000000002 softirq=13572/13572 fqs=0 
rcu: 	 (t=10502 jiffies g=11509 q=3264)
rcu: rcu_preempt kthread starved for 10503 jiffies! g11509 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29168    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2877 [inline]
 __schedule+0x817/0x1cc0 kernel/sched/core.c:3518
 schedule+0x92/0x180 kernel/sched/core.c:3562
 schedule_timeout+0x4db/0xfd0 kernel/time/timer.c:1803
 rcu_gp_fqs_loop kernel/rcu/tree.c:1971 [inline]
 rcu_gp_kthread+0x962/0x17b0 kernel/rcu/tree.c:2128
 kthread+0x357/0x430 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 9535 Comm: syz-executor.3 Not tainted 5.0.0+ #136
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1223
 print_cpu_stall kernel/rcu/tree.c:1360 [inline]
 check_cpu_stall kernel/rcu/tree.c:1434 [inline]
 rcu_pending kernel/rcu/tree.c:3103 [inline]
 rcu_sched_clock_irq.cold+0x500/0xa4a kernel/rcu/tree.c:2544
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
RIP: 0010:virt_spin_lock arch/x86/include/asm/qspinlock.h:83 [inline]
RIP: 0010:native_queued_spin_lock_slowpath+0xaa/0x9f0 kernel/locking/qspinlock.c:334
Code: 0f 1f 44 00 00 49 89 fe 49 89 fd 41 bc 01 00 00 00 49 c1 ee 03 41 83 e5 07 48 b8 00 00 00 00 00 fc ff df 49 01 c6 41 83 c5 03 <be> 04 00 00 00 48 89 df e8 19 2b 50 00 41 0f b6 06 41 38 c5 7c 08
RSP: 0018:ffff888061ec7330 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffe8ffffc6c4d0 RCX: ffffffff81580ec7
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffe8ffffc6c4d0
RBP: ffff888061ec73f0 R08: 1ffffd1ffff8d89a R09: fffff91ffff8d89b
R10: fffff91ffff8d89a R11: ffffe8ffffc6c4d3 R12: 0000000000000001
R13: 0000000000000003 R14: fffff91ffff8d89a R15: 0000000000000001
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:654 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:50 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:90 [inline]
 do_raw_spin_lock+0x20e/0x2e0 kernel/locking/spinlock_debug.c:113
 __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_lock+0x37/0x40 kernel/locking/spinlock.c:144
 spin_lock include/linux/spinlock.h:329 [inline]
 nf_ct_add_to_unconfirmed_list net/netfilter/nf_conntrack_core.c:487 [inline]
 init_conntrack.isra.0+0xa07/0x1170 net/netfilter/nf_conntrack_core.c:1478
 resolve_normal_ct net/netfilter/nf_conntrack_core.c:1519 [inline]
 nf_conntrack_in+0xd93/0x1410 net/netfilter/nf_conntrack_core.c:1679
 ipv4_conntrack_local+0x169/0x210 net/netfilter/nf_conntrack_proto.c:200
 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
 nf_hook_slow+0xbf/0x1f0 net/netfilter/core.c:511
 nf_hook include/linux/netfilter.h:244 [inline]
 __ip_local_out+0x403/0x880 net/ipv4/ip_output.c:113
 ip_local_out+0x2d/0x1b0 net/ipv4/ip_output.c:122
 ip_send_skb+0x42/0xf0 net/ipv4/ip_output.c:1465
 udp_send_skb.isra.0+0x6b2/0x1180 net/ipv4/udp.c:901
 udp_push_pending_frames+0x5c/0xf0 net/ipv4/udp.c:929
 udp_sendmsg+0x12ff/0x2820 net/ipv4/udp.c:1220
 inet_sendmsg+0x147/0x5d0 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:661
 __sys_sendto+0x262/0x380 net/socket.c:1932
 __do_sys_sendto net/socket.c:1944 [inline]
 __se_sys_sendto net/socket.c:1940 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1940
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458209
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6fa889dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000458209
RDX: 0000000000000045 RSI: 0000000020000040 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6fa889e6d4
R13: 00000000004c58b8 R14: 00000000004d9838 R15: 00000000ffffffff