rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10500 ticks this GP) idle=c0a/1/0x4000000000000002 softirq=105619/105619 fqs=0 
	(t=10500 jiffies g=166737 q=1530)
rcu: rcu_preempt kthread starved for 10500 jiffies! g166737 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29056    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:2818 [inline]
 __schedule+0x7cb/0x1560 kernel/sched/core.c:3445
 schedule+0xa8/0x260 kernel/sched/core.c:3509
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1807
 rcu_gp_fqs_loop kernel/rcu/tree.c:1589 [inline]
 rcu_gp_kthread+0x9b2/0x18b0 kernel/rcu/tree.c:1746
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 16701 Comm: syz-executor.4 Not tainted 5.2.0-rc1+ #31
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_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2625 [inline]
 rcu_sched_clock_irq.cold+0x4d1/0xbfd kernel/rcu/tree.c:2161
 update_process_times+0x32/0x80 kernel/time/timer.c:1639
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1298
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33b/0xdd0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1066
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </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 79 0a 51 00 41 0f b6 06 41 38 c5 7c 08
RSP: 0018:ffff888063056c88 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffe8ffffc6b0e0 RCX: ffffffff81580c77
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffe8ffffc6b0e0
RBP: ffff888063056d48 R08: 1ffffd1ffff8d61c R09: fffff91ffff8d61d
R10: fffff91ffff8d61c R11: ffffe8ffffc6b0e3 R12: 0000000000000001
R13: 0000000000000003 R14: fffff91ffff8d61c R15: 000000000000008e
 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:151
 spin_lock include/linux/spinlock.h:338 [inline]
 nf_ct_add_to_unconfirmed_list net/netfilter/nf_conntrack_core.c:522 [inline]
 init_conntrack.isra.0+0xa07/0x1170 net/netfilter/nf_conntrack_core.c:1511
 resolve_normal_ct net/netfilter/nf_conntrack_core.c:1552 [inline]
 nf_conntrack_in+0xd93/0x1410 net/netfilter/nf_conntrack_core.c:1712
 ipv4_conntrack_local+0x169/0x210 net/netfilter/nf_conntrack_proto.c:200
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:260 [inline]
 __ip_local_out+0x403/0x880 net/ipv4/ip_output.c:114
 ip_local_out+0x2d/0x1b0 net/ipv4/ip_output.c:123
 __ip_queue_xmit+0x86f/0x1bf0 net/ipv4/ip_output.c:503
 sctp_v4_xmit+0x1a8/0x200 net/sctp/protocol.c:991
 sctp_packet_transmit+0x1bb8/0x36e0 net/sctp/output.c:641
 sctp_packet_singleton net/sctp/outqueue.c:787 [inline]
 sctp_outq_flush_ctrl.constprop.0+0x73c/0xd30 net/sctp/outqueue.c:918
 sctp_outq_flush+0xe8/0x2780 net/sctp/outqueue.c:1200
 sctp_outq_uncork+0x6c/0x80 net/sctp/outqueue.c:772
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1791 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1194 [inline]
 sctp_do_sm+0x504/0x50e0 net/sctp/sm_sideeffect.c:1165
 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:88
 __sctp_connect+0x8c3/0xcd0 net/sctp/socket.c:1226
 __sctp_setsockopt_connectx+0x133/0x1a0 net/sctp/socket.c:1349
 sctp_setsockopt_connectx net/sctp/socket.c:1381 [inline]
 sctp_setsockopt net/sctp/socket.c:4666 [inline]
 sctp_setsockopt+0x22f1/0x6d10 net/sctp/socket.c:4623
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3130
 __sys_setsockopt+0x17a/0x280 net/socket.c:2078
 __do_sys_setsockopt net/socket.c:2089 [inline]
 __se_sys_setsockopt net/socket.c:2086 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2086
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459279
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc448ff3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459279
RDX: 000000000000006e RSI: 0000000000000084 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000010 R09: 0000000000000000
R10: 0000000020000100 R11: 0000000000000246 R12: 00007fc448ff46d4
R13: 00000000004cea50 R14: 00000000004dceb8 R15: 00000000ffffffff