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BUG: KCSAN: data-race in tick_sched_do_timer / tick_sched_do_timer

write to 0xffffffff85caf310 of 4 bytes by interrupt on cpu 1:
 tick_sched_do_timer+0xc0/0xe0 kernel/time/tick-sched.c:132
 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1289
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x288/0x600 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 __read_once_size include/linux/compiler.h:227 [inline]
 check_kcov_mode kernel/kcov.c:70 [inline]
 __sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:102
 tcp_options_write+0x11e/0x5e0 net/ipv4/tcp_output.c:490
 __tcp_transmit_skb+0x594/0x1cd0 net/ipv4/tcp_output.c:1110
 __tcp_send_ack+0x246/0x300 net/ipv4/tcp_output.c:3685
 tcp_send_ack+0x34/0x40 net/ipv4/tcp_output.c:3691
 tcp_cleanup_rbuf+0x130/0x360 net/ipv4/tcp.c:1575
 tcp_recvmsg+0x633/0x1a30 net/ipv4/tcp.c:2179
 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838

read to 0xffffffff85caf310 of 4 bytes by interrupt on cpu 0:
 tick_sched_do_timer+0x33/0xe0 kernel/time/tick-sched.c:128
 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1289
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x288/0x600 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 find_watchpoint kernel/kcsan/core.c:94 [inline]
 __kcsan_check_watchpoint+0xed/0x180 kernel/kcsan/core.c:322
 __tsan_write4+0x18/0x40 kernel/kcsan/kcsan.c:30
 __rcu_read_unlock+0x56/0xe0 kernel/rcu/tree_plugin.h:388
 rcu_read_unlock include/linux/rcupdate.h:645 [inline]
 nf_ct_deliver_cached_events+0xb5/0x2a0 net/netfilter/nf_conntrack_ecache.c:225
 nf_conntrack_confirm include/net/netfilter/nf_conntrack_core.h:62 [inline]
 nf_confirm+0x27d/0x2b0 net/netfilter/nf_conntrack_proto.c:154
 ipv4_confirm+0xcf/0x160 net/netfilter/nf_conntrack_proto.c:169
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x83/0x160 net/netfilter/core.c:512

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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