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BUG: KCSAN: data-race in add_timer_on / timer_clear_idle

write to 0xffff88812c11cb24 of 1 bytes by task 0 on cpu 1:
 timer_clear_idle+0x2e/0x40 kernel/time/timer.c:1687
 tick_nohz_idle_retain_tick+0x3e/0x40 kernel/time/tick-sched.c:1012
 cpuidle_idle_call kernel/sched/idle.c:210 [inline]
 do_idle+0x287/0x310 kernel/sched/idle.c:276
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:372
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

read to 0xffff88812c11cb24 of 1 bytes by interrupt on cpu 0:
 forward_timer_base kernel/time/timer.c:900 [inline]
 add_timer_on+0x218/0x3b0 kernel/time/timer.c:1183
 clocksource_watchdog+0x729/0x760 kernel/time/clocksource.c:303
 call_timer_fn+0x30/0x2a0 kernel/time/timer.c:1416
 expire_timers+0x116/0x290 kernel/time/timer.c:1461
 __run_timers+0x443/0x500 kernel/time/timer.c:1792
 run_timer_softirq+0x2e/0x60 kernel/time/timer.c:1805
 __do_softirq+0x198/0x360 kernel/softirq.c:298
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x5d/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu+0x115/0x120 kernel/softirq.c:423
 sysvec_apic_timer_interrupt+0xba/0xd0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:592

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8681 Comm: syz-fuzzer Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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