syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10500 ticks this GP) idle=a82/1/0x4000000000000000 softirq=48852/48853 fqs=5134 
	(t=10502 jiffies g=89085 q=1248)
NMI backtrace for cpu 0
CPU: 0 PID: 21830 Comm: syz-executor.2 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x222/0x2a7 kernel/rcu/tree_stall.h:341
 print_cpu_stall kernel/rcu/tree_stall.h:622 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:697 [inline]
 rcu_pending kernel/rcu/tree.c:3830 [inline]
 rcu_sched_clock_irq.cold+0x4f7/0x11dd kernel/rcu/tree.c:2650
 update_process_times+0x16d/0x200 kernel/time/timer.c:1796
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1369
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x1c0/0xe40 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x27/0x60 kernel/kcov.c:197
Code: 1f 40 00 65 8b 05 e9 c9 8e 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b 14 25 00 f0 01 00 a9 00 01 ff 00 74 0e 85 c9 74 35 <8b> 82 34 15 00 00 85 c0 74 2b 8b 82 10 15 00 00 83 f8 02 75 20 48
RSP: 0018:ffffc90000007570 EFLAGS: 00000206
RAX: 0000000000000301 RBX: ffffc900000076a8 RCX: 0000000000000100
RDX: ffff8880778f2340 RSI: ffffffff87b0ebc4 RDI: 0000000000000003
RBP: 0000000000000004 R08: 0000000000000000 R09: ffffffff87b0ea58
R10: ffffffff87b0f5c9 R11: 0000000000000004 R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000007668
 ipv6_get_saddr_eval net/ipv6/addrconf.c:1636 [inline]
 ipv6_get_saddr_eval+0x1d4/0x1030 net/ipv6/addrconf.c:1507
 __ipv6_dev_get_saddr+0x1f4/0x5c0 net/ipv6/addrconf.c:1682
 ipv6_dev_get_saddr+0x832/0xba0 net/ipv6/addrconf.c:1817
 ip6_route_get_saddr include/net/ip6_route.h:145 [inline]
 ip6_dst_lookup_tail+0xc83/0x1740 net/ipv6/ip6_output.c:1069
 icmpv6_route_lookup+0x9e/0x4d0 net/ipv6/icmp.c:365
 icmp6_send+0x11fd/0x22a0 net/ipv6/icmp.c:597
 __icmpv6_send include/linux/icmpv6.h:28 [inline]
 icmpv6_send include/linux/icmpv6.h:49 [inline]
 ip6_link_failure+0x2d/0x510 net/ipv6/route.c:2655
 dst_link_failure include/net/dst.h:427 [inline]
 ndisc_error_report+0xc7/0x1c0 net/ipv6/ndisc.c:712
 neigh_invalidate+0x20d/0x560 net/core/neighbour.c:994
 neigh_timer_handler+0xd43/0x10e0 net/core/neighbour.c:1081
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1431
 expire_timers kernel/time/timer.c:1476 [inline]
 __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1745
 __run_timers kernel/time/timer.c:1726 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1758
 __do_softirq+0x29b/0x9f6 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu kernel/softirq.c:422 [inline]
 irq_exit_rcu+0x134/0x200 kernel/softirq.c:434
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x60 kernel/kcov.c:197
Code: 81 e1 00 01 00 00 65 48 8b 14 25 00 f0 01 00 a9 00 01 ff 00 74 0e 85 c9 74 35 8b 82 34 15 00 00 85 c0 74 2b 8b 82 10 15 00 00 <83> f8 02 75 20 48 8b 8a 18 15 00 00 8b 92 14 15 00 00 48 8b 01 48
RSP: 0018:ffffc90001c974f8 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff8880139e1080 RCX: 0000000000000000
RDX: ffff8880778f2340 RSI: ffffffff87af28be RDI: 0000000000000003
RBP: ffff88807d248b80 R08: 00000000000000ff R09: 0000000000000000
R10: ffffffff87af28ac R11: 0000000000000000 R12: ffff88807d248c34
R13: ffff8880751b00c0 R14: 0000000000000000 R15: 0000000000000000
 ip6_finish_output2+0x11e/0x1700 net/ipv6/ip6_output.c:103
 __ip6_finish_output net/ipv6/ip6_output.c:182 [inline]
 __ip6_finish_output+0x4c1/0xe10 net/ipv6/ip6_output.c:161
 ip6_finish_output+0x35/0x200 net/ipv6/ip6_output.c:192
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:215
 dst_output include/net/dst.h:448 [inline]
 ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:179
 ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1904
 ip6_push_pending_frames+0xdd/0x100 net/ipv6/ip6_output.c:1924
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x2b1b/0x3930 net/ipv6/raw.c:956
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:674
 ____sys_sendmsg+0x331/0x810 net/socket.c:2350
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404
 __sys_sendmmsg+0x195/0x470 net/socket.c:2490
 __do_sys_sendmmsg net/socket.c:2519 [inline]
 __se_sys_sendmmsg net/socket.c:2516 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2516
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x466459
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fef73b0c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459
RDX: 03fffffffffffe9f RSI: 00000000200092c0 RDI: 0000000000000006
RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffc5ac132cf R14: 00007fef73b0c300 R15: 0000000000022000