syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=e12/1/0x4000000000000002 softirq=146459/146460 fqs=5249 
	(t=10502 jiffies g=160785 q=4273)
NMI backtrace for cpu 0
CPU: 0 PID: 11739 Comm: syz-executor.4 Not tainted 5.3.0-rc8+ #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+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:2736 [inline]
 rcu_sched_clock_irq.cold+0x4dd/0xc13 kernel/rcu/tree.c:2183
 update_process_times+0x32/0x80 kernel/time/timer.c:1639
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 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_cmp4+0x16/0x20 kernel/kcov.c:191
Code: 48 89 e5 48 8b 4d 08 e8 d8 fe ff ff 5d c3 66 0f 1f 44 00 00 55 89 f2 89 fe bf 05 00 00 00 48 89 e5 48 8b 4d 08 e8 ba fe ff ff <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 f2 48 89 fe bf 07 00 00 00
RSP: 0018:ffff8880584868e8 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000002 RBX: ffff8880962f3e38 RCX: ffffffff85c65b39
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: ffff8880584868e8 R08: ffff888093b805c0 R09: 0000000000000000
R10: fffffbfff134afaf R11: ffff888093b805c0 R12: dffffc0000000000
R13: ffff8880962f3b40 R14: ffff8880962f3ed0 R15: 0000000000000000
 hhf_dequeue+0xb9/0xa20 net/sched/sch_hhf.c:434
 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+0x16f1/0x3650 net/core/dev.c:3838
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902
 br_dev_queue_push_xmit+0x3f3/0x5c0 net/bridge/br_forward.c:52
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 br_forward_finish+0xfa/0x400 net/bridge/br_forward.c:65
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 __br_forward+0x641/0xb00 net/bridge/br_forward.c:109
 deliver_clone+0x61/0xc0 net/bridge/br_forward.c:125
 maybe_deliver+0x2c7/0x390 net/bridge/br_forward.c:181
 br_flood+0x13a/0x3d0 net/bridge/br_forward.c:223
 br_dev_xmit+0x98c/0x15a0 net/bridge/br_device.c:100
 __netdev_start_xmit include/linux/netdevice.h:4406 [inline]
 netdev_start_xmit include/linux/netdevice.h:4420 [inline]
 xmit_one net/core/dev.c:3280 [inline]
 dev_hard_start_xmit+0x1a3/0x9c0 net/core/dev.c:3296
 __dev_queue_xmit+0x2b15/0x3650 net/core/dev.c:3869
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902
 neigh_hh_output include/net/neighbour.h:500 [inline]
 neigh_output include/net/neighbour.h:509 [inline]
 ip6_finish_output2+0xf58/0x2520 net/ipv6/ip6_output.c:116
 ip6_fragment+0x1d8d/0x2560 net/ipv6/ip6_output.c:858
 __ip6_finish_output+0x577/0xa50 net/ipv6/ip6_output.c:140
 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0x235/0x7c0 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 ip6_local_out+0xbb/0x184 net/ipv6/output_core.c:179
 ip6_send_skb+0xbb/0x300 net/ipv6/ip6_output.c:1791
 udp_v6_send_skb.isra.0+0x839/0x14c0 net/ipv6/udp.c:1167
 udpv6_sendmsg+0x21dc/0x2990 net/ipv6/udp.c:1464
 inet6_sendmsg+0x9e/0xe0 net/ipv6/af_inet6.c:576
 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
 __compat_sys_sendmsg net/compat.c:642 [inline]
 __do_compat_sys_sendmsg net/compat.c:649 [inline]
 __se_compat_sys_sendmsg net/compat.c:646 [inline]
 __ia32_compat_sys_sendmsg+0x7a/0xb0 net/compat.c:646
 do_syscall_32_irqs_on arch/x86/entry/common.c:332 [inline]
 do_fast_syscall_32+0x27b/0xdb3 arch/x86/entry/common.c:403
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f62a29
Code: b8 80 96 98 00 eb cc 8b 04 24 c3 8b 1c 24 c3 8b 34 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f5d5e0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000480
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000