rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10501 ticks this GP) idle=a0e/1/0x4000000000000002 softirq=108786/108786 fqs=0 
	(t=10502 jiffies g=161669 q=6753)
rcu: rcu_preempt kthread starved for 10503 jiffies! g161669 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:4158
 schedule_timeout+0x35c/0x850 kernel/time/timer.c:1898
 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 0
CPU: 0 PID: 32334 Comm: syz-executor.4 Not tainted 5.7.0-rc4-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:1727
 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+0x1a6/0xcc0 net/sched/sch_sfq.c:492
Code: 00 66 44 89 63 1a 48 8b 9d 28 03 00 00 48 8d 7b 12 48 89 f8 48 c1 e8 03 42 0f b6 14 30 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 <84> d2 0f 85 2b 0a 00 00 44 0f b7 63 12 48 8b 9d 00 03 00 00 4d 89
RSP: 0018:ffffc90001b071d0 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000003 RBX: ffff888038409bc8 RCX: ffffc90011ef5000
RDX: 0000000000000000 RSI: ffffffff86467fd2 RDI: ffff888038409bda
RBP: ffff88809e5bc000 R08: ffff888038c540c0 R09: fffff52000360e2c
R10: 0000000000000003 R11: fffff52000360e2b R12: 0000000000000000
R13: ffff888038409be2 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:3704 [inline]
 __dev_queue_xmit+0x1d07/0x30a0 net/core/dev.c:4021
 neigh_hh_output include/net/neighbour.h:499 [inline]
 neigh_output include/net/neighbour.h:508 [inline]
 ip_finish_output2+0x17b7/0x2610 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:306 [inline]
 __ip_finish_output+0x5f3/0xbd0 net/ipv4/ip_output.c:288
 ip_finish_output+0x34/0x1f0 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0x1fe/0x620 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:435 [inline]
 ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:125
 __ip_queue_xmit+0x863/0x1c20 net/ipv4/ip_output.c:530
 __tcp_transmit_skb+0x1a07/0x3760 net/ipv4/tcp_output.c:1238
 tcp_transmit_skb net/ipv4/tcp_output.c:1254 [inline]
 tcp_write_xmit+0xf9e/0x5c10 net/ipv4/tcp_output.c:2517
 __tcp_push_pending_frames+0xaa/0x330 net/ipv4/tcp_output.c:2693
 tcp_push+0x472/0x6f0 net/ipv4/tcp.c:725
 tcp_sendmsg_locked+0x15ea/0x3210 net/ipv4/tcp.c:1390
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1433
 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_sendto+0x220/0x330 net/socket.c:2000
 __do_sys_sendto net/socket.c:2012 [inline]
 __se_sys_sendto net/socket.c:2008 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2008
 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:00007f99b694ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000500f60 RCX: 000000000045c829
RDX: 000000000000fe6a RSI: 00000000200012c0 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000170
R10: 0000000000000011 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a0e R14: 00000000004ccc56 R15: 00007f99b694b6d4