rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10501 ticks this GP) idle=ce6/1/0x4000000000000002 softirq=337518/337518 fqs=0 
	(t=10502 jiffies g=533153 q=919)
rcu: rcu_preempt kthread starved for 10503 jiffies! g533153 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I28960    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:2817 [inline]
 __schedule+0x7cb/0x1560 kernel/sched/core.c:3444
 schedule+0xa8/0x260 kernel/sched/core.c:3508
 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:254
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 1520 Comm: syz-executor.3 Not tainted 5.2.0-rc1+ #1
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:1040 [inline]
 smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1065
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:68 [inline]
RIP: 0010:write_comp_data+0x9/0x70 kernel/kcov.c:123
Code: 12 00 00 8b 80 e4 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 c0 fd 01 00 <65> 8b 05 b8 58 91 7e a9 00 01 1f 00 75 51 41 8b 80 e0 12 00 00 83
RSP: 0018:ffff888067237420 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000002 RBX: 0000000000000003 RCX: ffffffff86122806
RDX: 0000000000000011 RSI: 0000000000000011 RDI: 0000000000000001
RBP: ffff888067237440 R08: ffff8880a505e200 R09: ffffed1015d06be0
R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: ffffffff880d5600
R13: 0000000000000008 R14: 0000000000000000 R15: 0000000000000011
 xfrm_flowi_sport include/net/xfrm.h:851 [inline]
 __xfrm6_selector_match net/xfrm/xfrm_policy.c:213 [inline]
 xfrm_selector_match+0x426/0xfc0 net/xfrm/xfrm_policy.c:225
 xfrm_sk_policy_lookup+0x143/0x510 net/xfrm/xfrm_policy.c:2171
 xfrm_lookup_with_ifid+0x1de/0x2070 net/xfrm/xfrm_policy.c:3035
 xfrm_lookup net/xfrm/xfrm_policy.c:3172 [inline]
 xfrm_lookup_route+0x3b/0x1f0 net/xfrm/xfrm_policy.c:3183
 ip6_dst_lookup_flow+0x189/0x220 net/ipv6/ip6_output.c:1100
 inet6_csk_route_socket+0x85d/0xf40 net/ipv6/inet6_connection_sock.c:110
 inet6_csk_xmit+0x110/0x5d0 net/ipv6/inet6_connection_sock.c:125
 l2tp_xmit_core net/l2tp/l2tp_core.c:1033 [inline]
 l2tp_xmit_skb+0x1112/0x13e0 net/l2tp/l2tp_core.c:1135
 pppol2tp_sendmsg+0x4a2/0x6b0 net/l2tp/l2tp_ppp.c:329
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:671
 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2292
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2387
 __do_sys_sendmmsg net/socket.c:2416 [inline]
 __se_sys_sendmmsg net/socket.c:2413 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2413
 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:00007f3fb3de1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459279
RDX: 04000000000004ae RSI: 0000000020005fc0 RDI: 0000000000000004
RBP: 000000000075bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000a R11: 0000000000000246 R12: 00007f3fb3de26d4
R13: 00000000004c65fc R14: 00000000004db280 R15: 00000000ffffffff