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BUG: KCSAN: data-race in tick_sched_do_timer / tick_sched_do_timer

write to 0xffffffff8764e210 of 4 bytes by interrupt on cpu 1:
 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
 get_ctx kernel/kcsan/core.c:193 [inline]
 check_access kernel/kcsan/core.c:579 [inline]
 __tsan_read1+0x83/0x110 kernel/kcsan/core.c:767
 __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]
 nfct_seqadj include/net/netfilter/nf_conntrack_seqadj.h:26 [inline]
 nf_ct_seq_offset+0x43/0xd0 net/netfilter/nf_conntrack_seqadj.c:224
 tcp_in_window net/netfilter/nf_conntrack_proto_tcp.c:492 [inline]
 nf_conntrack_tcp_packet+0x565/0x2fe0 net/netfilter/nf_conntrack_proto_tcp.c:1091
 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+0x24c/0x3420 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 0xffffffff8764e210 of 4 bytes by interrupt on cpu 0:
 tick_sched_do_timer+0x2e/0xd0 kernel/time/tick-sched.c:137
 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
 __tsan_read4+0x0/0x110 kernel/kcsan/core.c:584
 xt_get_this_cpu_counter include/linux/netfilter/x_tables.h:434 [inline]
 ipt_do_table+0x6b1/0xe70 net/ipv4/netfilter/ip_tables.c:298
 iptable_raw_hook+0x44/0x60 net/ipv4/netfilter/iptable_raw.c:44
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x7c/0x160 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:262 [inline]
 __ip_local_out+0x1f3/0x2b0 net/ipv4/ip_output.c:114
 ip_local_out+0x2d/0x90 net/ipv4/ip_output.c:123
 __ip_queue_xmit+0x3a6/0xa40 net/ipv4/ip_output.c:530
 ip_queue_xmit+0x3e/0x50 include/net/ip.h:237
 __tcp_transmit_skb+0xe0c/0x1d80 net/ipv4/tcp_output.c:1238
 __tcp_send_ack+0x22c/0x2f0 net/ipv4/tcp_output.c:3779
 tcp_send_ack+0x2d/0x40 net/ipv4/tcp_output.c:3785
 tcp_cleanup_rbuf+0x124/0x340 net/ipv4/tcp.c:1575
 tcp_recvmsg+0x686/0x1ba0 net/ipv4/tcp.c:2183
 inet_recvmsg+0xc1/0x250 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_recvmsg+0x8e/0xb0 net/socket.c:900
 sock_read_iter+0x185/0x230 net/socket.c:982
 call_read_iter include/linux/fs.h:1901 [inline]
 new_sync_read+0x416/0x450 fs/read_write.c:415
 __vfs_read+0x9e/0xb0 fs/read_write.c:428
 vfs_read fs/read_write.c:462 [inline]
 vfs_read+0x13e/0x2b0 fs/read_write.c:447
 ksys_read+0x16a/0x1a0 fs/read_write.c:588
 __do_sys_read fs/read_write.c:598 [inline]
 __se_sys_read fs/read_write.c:596 [inline]
 __x64_sys_read+0x49/0x60 fs/read_write.c:596
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8925 Comm: syz-fuzzer 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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