syzbot

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BUG: KMSAN: uninit-value in calc_wheel_index+0xb4/0x440 kernel/time/timer.c:499
CPU: 1 PID: 8 Comm: rcu_sched Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 calc_wheel_index+0xb4/0x440 kernel/time/timer.c:499
 __internal_add_timer kernel/time/timer.c:547 [inline]
 internal_add_timer kernel/time/timer.c:590 [inline]
 __mod_timer+0x1a0c/0x2c40 kernel/time/timer.c:1055
 schedule_timeout+0x3e2/0x570 kernel/time/timer.c:1800
 rcu_gp_kthread+0x21e1/0x38d0 kernel/rcu/tree.c:2230
 kthread+0x539/0x720 kernel/kthread.c:239
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:406

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:528
 do_timer+0xa0/0xc0 kernel/time/timekeeping.c:2231
 tick_do_update_jiffies64+0x28a/0x4b0 kernel/time/tick-sched.c:88
 tick_sched_do_timer kernel/time/tick-sched.c:136 [inline]
 tick_sched_timer+0xfc/0x4b0 kernel/time/tick-sched.c:1187
 __run_hrtimer kernel/time/hrtimer.c:1349 [inline]
 __hrtimer_run_queues+0xc03/0x15d0 kernel/time/hrtimer.c:1411
 hrtimer_interrupt+0x426/0xaf0 kernel/time/hrtimer.c:1469
 local_apic_timer_interrupt+0x66/0x230 arch/x86/kernel/apic/apic.c:1025
 smp_apic_timer_interrupt+0x5a/0x90 arch/x86/kernel/apic/apic.c:1053
Local variable description: ----flags.i.i.i.i@_raw_spin_lock_irqsave
Variable was created at:
 _raw_spin_lock_irqsave+0x45/0xf0 kernel/locking/spinlock.c:150
 try_to_wake_up+0xec/0x20a0 kernel/sched/core.c:1991
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