syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=e36/1/0x4000000000000002 softirq=43203/43204 fqs=5245 
rcu: 	 (t=10500 jiffies g=49561 q=398)
NMI backtrace for cpu 1
CPU: 1 PID: 22777 Comm: syz-executor.4 Not tainted 5.0.0+ #116
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:1211
 print_cpu_stall kernel/rcu/tree.c:1348 [inline]
 check_cpu_stall kernel/rcu/tree.c:1422 [inline]
 rcu_pending kernel/rcu/tree.c:3018 [inline]
 rcu_check_callbacks.cold+0x500/0xa4a kernel/rcu/tree.c:2521
 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:cpu_relax arch/x86/include/asm/processor.h:666 [inline]
RIP: 0010:virt_spin_lock arch/x86/include/asm/qspinlock.h:84 [inline]
RIP: 0010:native_queued_spin_lock_slowpath+0x132/0x970 kernel/locking/qspinlock.c:337
Code: 00 00 00 48 8b 45 d0 65 48 33 04 25 28 00 00 00 0f 85 a2 06 00 00 48 81 c4 98 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 f3 90 <e9> 73 ff ff ff 8b 45 98 4c 8d 65 d8 3d 00 01 00 00 0f 84 e5 00 00
RSP: 0018:ffff8880980cee18 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffe8ffffd713e0 RCX: ffffffff81579127
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffe8ffffd713e0
RBP: ffff8880980ceed8 R08: 1ffffd1ffffae27c R09: fffff91ffffae27d
R10: fffff91ffffae27c R11: ffffe8ffffd713e3 R12: 0000000000000001
R13: 0000000000000003 R14: fffff91ffffae27c R15: 000000000000000b
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:653 [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
 ipv6_conntrack_local+0x1e/0x30 net/netfilter/nf_conntrack_proto.c:194
 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]
 NF_HOOK include/linux/netfilter.h:287 [inline]
 ip6_xmit+0x11c6/0x20c0 net/ipv6/ip6_output.c:275
 sctp_v6_xmit+0x313/0x660 net/sctp/ipv6.c:232
 sctp_packet_transmit+0x1b8b/0x3660 net/sctp/output.c:641
 sctp_packet_singleton net/sctp/outqueue.c:787 [inline]
 sctp_outq_flush_ctrl.constprop.0+0x741/0xd40 net/sctp/outqueue.c:918
 sctp_outq_flush+0xe8/0x2790 net/sctp/outqueue.c:1200
 sctp_outq_uncork+0x6c/0x80 net/sctp/outqueue.c:772
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1820 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
 sctp_do_sm+0x513/0x5390 net/sctp/sm_sideeffect.c:1191
 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:88
 __sctp_connect+0x8cd/0xce0 net/sctp/socket.c:1226
 sctp_connect net/sctp/socket.c:4818 [inline]
 sctp_inet_connect+0x2a2/0x350 net/sctp/socket.c:4834
 __sys_connect+0x266/0x330 net/socket.c:1685
 __do_sys_connect net/socket.c:1696 [inline]
 __se_sys_connect net/socket.c:1693 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1693
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457f29
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:00007fded9621c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457f29
RDX: 000000000000001c RSI: 0000000020000200 RDI: 0000000000000004
RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fded96226d4
R13: 00000000004be35b R14: 00000000004ceae8 R15: 00000000ffffffff