rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10500 ticks this GP) idle=93a/1/0x4000000000000002 softirq=9636/9636 fqs=0 
	(t=10501 jiffies g=6741 q=109)
rcu: rcu_preempt kthread starved for 10502 jiffies! g6741 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I29360    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3265 [inline]
 __schedule+0x76e/0x17a0 kernel/sched/core.c:3937
 schedule+0xd9/0x260 kernel/sched/core.c:4004
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1893
 rcu_gp_fqs_loop kernel/rcu/tree.c:1639 [inline]
 rcu_gp_kthread+0x9b2/0x18d0 kernel/rcu/tree.c:1799
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8608 Comm: syz-executor694 Not tainted 5.3.0-rc6-next-20190830 #75
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:cpu_relax arch/x86/include/asm/processor.h:656 [inline]
RIP: 0010:virt_spin_lock arch/x86/include/asm/qspinlock.h:99 [inline]
RIP: 0010:native_queued_spin_lock_slowpath+0x132/0x9f0 kernel/locking/qspinlock.c:325
Code: 00 00 00 48 8b 45 d0 65 48 33 04 25 28 00 00 00 0f 85 37 07 00 00 48 81 c4 98 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 f3 90 <e9> 73 ff ff ff 8b 45 98 4c 8d 65 d8 3d 00 01 00 00 0f 84 e5 00 00
RSP: 0018:ffff8880a47772f8 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff8880a5bf50e8 RCX: ffffffff815924c7
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880a5bf50e8
RBP: ffff8880a47773b8 R08: 1ffff11014b7ea1d R09: ffffed1014b7ea1e
R10: ffffed1014b7ea1d R11: ffff8880a5bf50eb R12: 0000000000000001
R13: 0000000000000003 R14: ffffed1014b7ea1d R15: 0000000000000001
FS:  0000555555bd0880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc7e0d83a0 CR3: 00000000964fe000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:642 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:50 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:81 [inline]
 do_raw_spin_lock+0x20e/0x2e0 kernel/locking/spinlock_debug.c:113
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
 _raw_spin_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:343 [inline]
 sch_tree_lock include/net/sch_generic.h:544 [inline]
 hhf_change+0x2e3/0xad0 net/sched/sch_hhf.c:537
 qdisc_change net/sched/sch_api.c:1321 [inline]
 tc_modify_qdisc+0xfcf/0x1c50 net/sched/sch_api.c:1623
 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5223
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5241
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:657
 ___sys_sendmsg+0x803/0x920 net/socket.c:2311
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2356
 __do_sys_sendmsg net/socket.c:2365 [inline]
 __se_sys_sendmsg net/socket.c:2363 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363
 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x442399
Code: e8 9c 07 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 3b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc7e0d8398 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000442399
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003
RBP: 0000000000036966 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000004032f0 R14: 0000000000000000 R15: 0000000000000000
NMI backtrace for cpu 1
CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.3.0-rc6-next-20190830 #75
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+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:2795 [inline]
 rcu_sched_clock_irq.cold+0x4fd/0xc12 kernel/rcu/tree.c:2244
 update_process_times+0x2d/0x70 kernel/time/timer.c:1724
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1299
 __run_hrtimer kernel/time/hrtimer.c:1504 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1566
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1628
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1106 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1131
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x0/0x20 kernel/kcov.c:174
Code: 5d c3 0f 1f 84 00 00 00 00 00 55 48 89 f2 48 89 fe bf 06 00 00 00 48 89 e5 48 8b 4d 08 e8 18 ff ff ff 5d c3 66 0f 1f 44 00 00 <55> 40 0f b6 d6 40 0f b6 f7 bf 01 00 00 00 48 89 e5 48 8b 4d 08 e8
RSP: 0000:ffff8880a99069a0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: ffff8880a5bf52f8 RCX: ffffffff85cb69b9
RDX: ffff8880a5bf52f8 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880a99069f8 R08: ffff8880a98f2440 R09: fffffbfff14ed341
R10: ffff8880a98f2da8 R11: ffff8880a98f2440 R12: dffffc0000000000
R13: ffff8880a5bf5000 R14: 0000000000000001 R15: 0000000000000000
 dequeue_skb net/sched/sch_generic.c:258 [inline]
 qdisc_restart net/sched/sch_generic.c:361 [inline]
 __qdisc_run+0x1e7/0x19d0 net/sched/sch_generic.c:379
 __dev_xmit_skb net/core/dev.c:3533 [inline]
 __dev_queue_xmit+0x16f1/0x37c0 net/core/dev.c:3838
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902
 br_dev_queue_push_xmit+0x3f3/0x5e0 net/bridge/br_forward.c:52
 br_nf_dev_queue_xmit+0x34e/0x14b0 net/bridge/br_netfilter_hooks.c:796
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 br_nf_post_routing+0x1502/0x1d30 net/bridge/br_netfilter_hooks.c:844
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:260 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 br_forward_finish+0x215/0x400 net/bridge/br_forward.c:65
 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015
 br_nf_forward_finish+0x66c/0xa90 net/bridge/br_netfilter_hooks.c:560
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 br_nf_forward_ip net/bridge/br_netfilter_hooks.c:630 [inline]
 br_nf_forward_ip+0xc74/0x21e0 net/bridge/br_netfilter_hooks.c:571
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:260 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 __br_forward+0x393/0xb00 net/bridge/br_forward.c:109
 deliver_clone+0x61/0xc0 net/bridge/br_forward.c:125
 br_flood+0x325/0x3d0 net/bridge/br_forward.c:232
 br_handle_frame_finish+0xb46/0x1670 net/bridge/br_input.c:162
 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015
 br_nf_pre_routing_finish_ipv6+0x6fa/0xdb0 net/bridge/br_netfilter_ipv6.c:206
 NF_HOOK include/linux/netfilter.h:305 [inline]
 br_nf_pre_routing_ipv6+0x456/0x840 net/bridge/br_netfilter_ipv6.c:236
 br_nf_pre_routing+0x1743/0x2360 net/bridge/br_netfilter_hooks.c:501
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:223 [inline]
 br_handle_frame+0x806/0x1340 net/bridge/br_input.c:348
 __netif_receive_skb_core+0xfc1/0x3060 net/core/dev.c:4907
 __netif_receive_skb_one_core+0xa8/0x1a0 net/core/dev.c:5004
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5120
 process_backlog+0x206/0x750 net/core/dev.c:5951
 napi_poll net/core/dev.c:6388 [inline]
 net_rx_action+0x50a/0x10d0 net/core/dev.c:6456
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:603 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352