rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=e16/1/0x4000000000000002 softirq=126591/126591 fqs=5247 rcu: (t=10500 jiffies g=200909 q=232) NMI backtrace for cpu 0 CPU: 0 PID: 18338 Comm: syz-executor4 Not tainted 4.20.0-rc6-next-20181217+ #172 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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+0x16f/0x1bc kernel/rcu/tree.c:1211 print_cpu_stall.cold.70+0x218/0x40a kernel/rcu/tree.c:1348 check_cpu_stall kernel/rcu/tree.c:1422 [inline] rcu_pending kernel/rcu/tree.c:3018 [inline] rcu_check_callbacks+0xf3b/0x13f0 kernel/rcu/tree.c:2521 update_process_times+0x2d/0x70 kernel/time/timer.c:1635 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:161 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1271 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline] smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1060 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:__sanitizer_cov_trace_switch+0x53/0x90 kernel/kcov.c:223 Code: 75 2d 4c 8b 3e 31 db 49 89 f4 49 89 fd 4d 85 ff 74 1d 49 8b 74 dc 10 4c 89 ea 4c 89 f7 48 83 c3 01 48 8b 4d 08 e8 ed fd ff ff <49> 39 df 75 e3 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 83 f8 08 41 be RSP: 0018:ffff8881927c6ea0 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000002 RBX: 0000000000000005 RCX: ffffffff86d2baa7 RDX: 0000000000000011 RSI: 000000000000003a RDI: 0000000000000001 RBP: ffff8881927c6ec8 R08: ffff8881d50323c0 R09: ffffed103b585b77 R10: ffffed103b585b77 R11: ffff8881dac2dbbb R12: ffffffff88e7bcc0 R13: 0000000000000011 R14: 0000000000000001 R15: 0000000000000008 xfrm_flowi_sport include/net/xfrm.h:913 [inline] __xfrm6_selector_match net/xfrm/xfrm_policy.c:209 [inline] xfrm_selector_match+0x3f7/0xf90 net/xfrm/xfrm_policy.c:221 xfrm_sk_policy_lookup+0x1c2/0x640 net/xfrm/xfrm_policy.c:2170 xfrm_lookup_with_ifid+0x2a1/0x2b80 net/xfrm/xfrm_policy.c:3038 xfrm_lookup net/xfrm/xfrm_policy.c:3175 [inline] xfrm_lookup_route+0x3c/0x1f0 net/xfrm/xfrm_policy.c:3186 ip6_dst_lookup_flow+0x1c6/0x270 net/ipv6/ip6_output.c:1091 inet6_csk_route_socket+0x8c6/0x1030 net/ipv6/inet6_connection_sock.c:110 inet6_csk_xmit+0x118/0x630 net/ipv6/inet6_connection_sock.c:125 l2tp_xmit_core net/l2tp/l2tp_core.c:1030 [inline] l2tp_xmit_skb+0x131f/0x1640 net/l2tp/l2tp_core.c:1132 pppol2tp_sendmsg+0x4b1/0x6c0 net/l2tp/l2tp_ppp.c:329 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:632 ___sys_sendmsg+0x51d/0x930 net/socket.c:2117 __sys_sendmmsg+0x246/0x6d0 net/socket.c:2212 __do_sys_sendmmsg net/socket.c:2241 [inline] __se_sys_sendmmsg net/socket.c:2238 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2238 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457669 Code: fd b3 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc776ab7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457669 RDX: 0800000000000059 RSI: 0000000020005fc0 RDI: 0000000000000006 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc776ab86d4 R13: 00000000004c3e4b R14: 00000000004d6ca8 R15: 00000000ffffffff