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BUG: KCSAN: data-race in internal_add_timer / update_process_times

write to 0xffff888237c1b658 of 8 bytes by interrupt on cpu 1:
 enqueue_timer kernel/time/timer.c:597 [inline]
 internal_add_timer+0x140/0x260 kernel/time/timer.c:609
 add_timer_on+0x262/0x2a0 kernel/time/timer.c:1180
 clocksource_watchdog+0x707/0x750 kernel/time/clocksource.c:303
 call_timer_fn+0x2e/0x1d0 kernel/time/timer.c:1431
 expire_timers+0x135/0x250 kernel/time/timer.c:1476
 __run_timers+0x358/0x420 kernel/time/timer.c:1745
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1758
 __do_softirq+0x12c/0x275 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu+0xaa/0xb0 kernel/softirq.c:422
 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
 check_kcov_mode kernel/kcov.c:165 [inline]
 write_comp_data kernel/kcov.c:218 [inline]
 __sanitizer_cov_trace_const_cmp4+0x31/0xa0 kernel/kcov.c:284
 wait_consider_task+0x194/0x19e0 kernel/exit.c:1298
 do_wait_thread kernel/exit.c:1397 [inline]
 do_wait+0x1b1/0x4a0 kernel/exit.c:1468
 kernel_wait4+0x13c/0x1a0 kernel/exit.c:1630
 __do_sys_wait4 kernel/exit.c:1658 [inline]
 __se_sys_wait4 kernel/exit.c:1654 [inline]
 __x64_sys_wait4+0x7a/0x100 kernel/exit.c:1654
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c1b658 of 8 bytes by interrupt on cpu 0:
 run_local_timers kernel/time/timer.c:1772 [inline]
 update_process_times+0x8c/0x150 kernel/time/timer.c:1795
 tick_sched_handle kernel/time/tick-sched.c:226 [inline]
 tick_sched_timer+0x191/0x210 kernel/time/tick-sched.c:1369
 __run_hrtimer+0x160/0x480 kernel/time/hrtimer.c:1537
 __hrtimer_run_queues kernel/time/hrtimer.c:1601 [inline]
 hrtimer_interrupt+0x380/0xaf0 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x6f/0x1c0 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x64/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
 acpi_idle_do_entry drivers/acpi/processor_idle.c:517 [inline]
 acpi_idle_enter+0x25b/0x2e0 drivers/acpi/processor_idle.c:652
 cpuidle_enter_state+0x2b6/0x750 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x3c/0x60 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:158 [inline]
 cpuidle_idle_call kernel/sched/idle.c:239 [inline]
 do_idle+0x193/0x230 kernel/sched/idle.c:300
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:397
 rest_init+0xc9/0xd0 init/main.c:721
 arch_call_rest_init+0xa/0xb
 start_kernel+0x59e/0x623 init/main.c:1064
 secondary_startup_64_no_verify+0xb0/0xbb

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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