rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10500 ticks this GP) idle=1b6/1/0x4000000000000002 softirq=19498/19498 fqs=0 
	(t=10502 jiffies g=29957 q=26)
rcu: rcu_preempt kthread starved for 10503 jiffies! g29957 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I28848    10      2 0x80004000
Call Trace:
 schedule+0xd0/0x2a0 kernel/sched/core.c:4157
 schedule_timeout+0x35c/0x850 kernel/time/timer.c:1897
 rcu_gp_fqs_loop kernel/rcu/tree.c:1674 [inline]
 rcu_gp_kthread+0x9bf/0x1960 kernel/rcu/tree.c:1836
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 12291 Comm: syz-executor.5 Not tainted 5.7.0-rc2-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:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x19b/0x1e5 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:475 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:549 [inline]
 rcu_pending kernel/rcu/tree.c:3225 [inline]
 rcu_sched_clock_irq.cold+0x55d/0xcfa kernel/rcu/tree.c:2296
 update_process_times+0x25/0x60 kernel/time/timer.c:1726
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x5ca/0xed0 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline]
 smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1138
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:sfq_dequeue+0x1d4/0xcc0 net/sched/sch_sfq.c:494
Code: 2b 0a 00 00 44 0f b7 63 12 48 8b 9d 00 03 00 00 4d 89 e7 4d 6b e4 38 4c 01 e3 4c 8d 6b 1a 4c 89 e8 48 c1 e8 03 42 0f b6 14 30 <4c> 89 e8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 d6 09 00 00 0f
RSP: 0018:ffffc90004aa70c0 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff13
RAX: 1ffff1100c3cfb7c RBX: ffff888061e7dbc8 RCX: ffffc900146d3000
RDX: 0000000000000000 RSI: ffffffff8646cc92 RDI: ffff888061e7dbda
RBP: ffff8880a6525000 R08: ffff8880a1a28100 R09: fffff52000954e0a
R10: 0000000000000003 R11: fffff52000954e09 R12: 0000000000001bc8
R13: ffff888061e7dbe2 R14: dffffc0000000000 R15: 000000000000007f
 dequeue_skb net/sched/sch_generic.c:263 [inline]
 qdisc_restart net/sched/sch_generic.c:366 [inline]
 __qdisc_run+0x1ac/0x17b0 net/sched/sch_generic.c:384
 __dev_xmit_skb net/core/dev.c:3772 [inline]
 __dev_queue_xmit+0x1d07/0x30a0 net/core/dev.c:4089
 neigh_hh_output include/net/neighbour.h:499 [inline]
 neigh_output include/net/neighbour.h:508 [inline]
 ip6_finish_output2+0xfb5/0x25b0 net/ipv6/ip6_output.c:117
 __ip6_finish_output+0x442/0xab0 net/ipv6/ip6_output.c:143
 ip6_finish_output+0x34/0x1f0 net/ipv6/ip6_output.c:153
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x239/0x810 net/ipv6/ip6_output.c:176
 dst_output include/net/dst.h:435 [inline]
 ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:179
 ip6_send_skb+0xb4/0x340 net/ipv6/ip6_output.c:1865
 ip6_push_pending_frames+0xbd/0xe0 net/ipv6/ip6_output.c:1885
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x2b3d/0x3900 net/ipv6/raw.c:956
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x308/0x7e0 net/socket.c:2362
 ___sys_sendmsg+0x100/0x170 net/socket.c:2416
 __sys_sendmmsg+0x195/0x480 net/socket.c:2506
 __do_sys_sendmmsg net/socket.c:2535 [inline]
 __se_sys_sendmmsg net/socket.c:2532 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2532
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c829
Code: 0d 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1a93843c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004fc320 RCX: 000000000045c829
RDX: 00000000000002e9 RSI: 0000000020000480 RDI: 0000000000000007
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008dd R14: 00000000004cb81f R15: 00007f1a938446d4