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BUG: KCSAN: data-race in add_timer_on / timer_clear_idle

write to 0xffff88812c11dbe4 of 1 bytes by task 0 on cpu 1:
 timer_clear_idle+0x42/0x50 kernel/time/timer.c:1676
 tick_nohz_restart_sched_tick kernel/time/tick-sched.c:850 [inline]
 __tick_nohz_idle_restart_tick+0x36/0x1b0 kernel/time/tick-sched.c:1151
 tick_nohz_idle_exit+0x1af/0x1e0 kernel/time/tick-sched.c:1192
 do_idle+0xb1/0x290 kernel/sched/idle.c:282
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361
 start_secondary+0x168/0x1b0 arch/x86/kernel/smpboot.c:264
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

read to 0xffff88812c11dbe4 of 1 bytes by interrupt on cpu 0:
 forward_timer_base kernel/time/timer.c:892 [inline]
 add_timer_on+0x220/0x2e0 kernel/time/timer.c:1172
 clocksource_watchdog+0x63f/0x760 kernel/time/clocksource.c:297
 call_timer_fn+0x5f/0x2f0 kernel/time/timer.c:1405
 expire_timers kernel/time/timer.c:1450 [inline]
 __run_timers kernel/time/timer.c:1774 [inline]
 __run_timers kernel/time/timer.c:1741 [inline]
 run_timer_softirq+0xbe3/0xcb0 kernel/time/timer.c:1787
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xbb/0xe0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0xe6/0x280 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60
 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690
 default_idle_call+0x1e/0x40 kernel/sched/idle.c:94
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x1c2/0x290 kernel/sched/idle.c:269
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361
 rest_init+0xec/0xf6 init/main.c:452
 arch_call_rest_init+0x17/0x37
 start_kernel+0x838/0x85e init/main.c:786
 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490
 x86_64_start_kernel+0x72/0x76 arch/x86/kernel/head64.c:471
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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