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BUG: KCSAN: data-race in tick_nohz_next_event / tick_sched_do_timer

write to 0xffffffff85f0ef50 of 4 bytes by interrupt on cpu 0:
 tick_sched_do_timer+0xb4/0xd0 kernel/time/tick-sched.c:141
 tick_sched_timer+0x3f/0xd0 kernel/time/tick-sched.c:1313
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x271/0x600 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x226/0x490 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113 [inline]
 smp_apic_timer_interrupt+0xd8/0x270 arch/x86/kernel/apic/apic.c:1138
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:759 [inline]
 kcsan_setup_watchpoint+0x25a/0x440 kernel/kcsan/core.c:542
 __nf_ct_ext_exist include/net/netfilter/nf_conntrack_extend.h:53 [inline]
 nf_ct_ext_exist include/net/netfilter/nf_conntrack_extend.h:58 [inline]
 __nf_ct_ext_find include/net/netfilter/nf_conntrack_extend.h:63 [inline]
 nf_conn_acct_find include/net/netfilter/nf_conntrack_acct.h:26 [inline]
 nf_ct_acct_add+0x48/0x90 net/netfilter/nf_conntrack_core.c:873
 nf_ct_acct_update include/net/netfilter/nf_conntrack_acct.h:75 [inline]
 __nf_ct_refresh_acct net/netfilter/nf_conntrack_core.c:1936 [inline]
 __nf_ct_refresh_acct+0x191/0x1a0 net/netfilter/nf_conntrack_core.c:1918
 nf_ct_refresh_acct include/net/netfilter/nf_conntrack.h:196 [inline]
 nf_conntrack_tcp_packet+0xc63/0x2fe0 net/netfilter/nf_conntrack_proto_tcp.c:1161
 nf_conntrack_handle_packet net/netfilter/nf_conntrack_core.c:1769 [inline]
 nf_conntrack_in+0x3fe/0xa60 net/netfilter/nf_conntrack_core.c:1863
 ipv4_conntrack_in+0x23/0x40 net/netfilter/nf_conntrack_proto.c:178
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x7c/0x160 net/netfilter/core.c:512
 nf_hook_slow_list+0x140/0x29f net/netfilter/core.c:550
 NF_HOOK_LIST include/linux/netfilter.h:343 [inline]
 ip_sublist_rcv+0x4f9/0x530 net/ipv4/ip_input.c:606
 ip_list_rcv+0x2f3/0x321 net/ipv4/ip_input.c:643
 __netif_receive_skb_list_ptype net/core/dev.c:5230 [inline]
 __netif_receive_skb_list_ptype net/core/dev.c:5219 [inline]
 __netif_receive_skb_list_core+0x368/0x5c0 net/core/dev.c:5278
 __netif_receive_skb_list net/core/dev.c:5330 [inline]
 netif_receive_skb_list_internal+0x5c7/0x810 net/core/dev.c:5425
 gro_normal_list.part.0+0x37/0xa0 net/core/dev.c:5536
 gro_normal_list net/core/dev.c:5549 [inline]
 gro_normal_one+0x14c/0x160 net/core/dev.c:5548
 napi_skb_finish net/core/dev.c:5876 [inline]
 napi_gro_receive+0x27d/0x2f0 net/core/dev.c:5908
 receive_buf+0x252/0x2ed0 drivers/net/virtio_net.c:1073
 virtnet_receive drivers/net/virtio_net.c:1335 [inline]
 virtnet_poll+0x343/0x790 drivers/net/virtio_net.c:1440
 napi_poll net/core/dev.c:6571 [inline]
 net_rx_action+0x3ad/0xac0 net/core/dev.c:6639
 __do_softirq+0x118/0x34a kernel/softirq.c:292
 run_ksoftirqd+0x41/0x60 kernel/softirq.c:604
 smpboot_thread_fn+0x374/0x4a0 kernel/smpboot.c:165
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffffffff85f0ef50 of 4 bytes by task 0 on cpu 1:
 tick_nohz_next_event+0x181/0x340 kernel/time/tick-sched.c:746
 __tick_nohz_idle_stop_tick kernel/time/tick-sched.c:964 [inline]
 tick_nohz_idle_stop_tick+0x3b9/0x680 kernel/time/tick-sched.c:994
 cpuidle_idle_call kernel/sched/idle.c:151 [inline]
 do_idle+0x1ad/0x290 kernel/sched/idle.c:269
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:361
 start_secondary+0x169/0x1b0 arch/x86/kernel/smpboot.c:268
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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