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BUG: KCSAN: data-race in kvm_arch_vcpu_load / pvclock_gtod_notify

write to 0xffffffff85fde628 of 4 bytes by interrupt on cpu 1:
 update_pvclock_gtod arch/x86/kvm/x86.c:1551 [inline]
 pvclock_gtod_notify+0x9f/0x260 arch/x86/kvm/x86.c:7123
 notifier_call_chain+0xd7/0x160 kernel/notifier.c:95
 __raw_notifier_call_chain kernel/notifier.c:396 [inline]
 raw_notifier_call_chain+0x37/0x50 kernel/notifier.c:403
 update_pvclock_gtod kernel/time/timekeeping.c:578 [inline]
 timekeeping_update+0x1b5/0x2d0 kernel/time/timekeeping.c:672
 timekeeping_advance+0x87d/0xd80 kernel/time/timekeeping.c:2120
 update_wall_time+0x19/0x20 kernel/time/timekeeping.c:2137
 tick_do_update_jiffies64+0x1a4/0x250 kernel/time/tick-sched.c:94
 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138
 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1292
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1638
 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
 alloc_pages_vma+0x0/0x3a0 mm/mempolicy.c:1701
 handle_mm_fault+0x21b/0x530 mm/memory.c:4010
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x3fb/0x9e0 arch/x86/mm/fault.c:1506
 do_page_fault+0x54/0x233 arch/x86/mm/fault.c:1530
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1202
 copy_user_enhanced_fast_string+0xe/0x30 arch/x86/lib/copy_user_64.S:204
 copy_page_to_iter_iovec lib/iov_iter.c:211 [inline]
 copy_page_to_iter+0x254/0x8b0 lib/iov_iter.c:900
 generic_file_buffered_read mm/filemap.c:2144 [inline]
 generic_file_read_iter+0x978/0x1440 mm/filemap.c:2324
 ext4_file_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0xfa/0x240 fs/ext4/file.c:65
 call_read_iter include/linux/fs.h:1889 [inline]
 new_sync_read+0x389/0x4f0 fs/read_write.c:414
 __vfs_read+0xb1/0xc0 fs/read_write.c:427
 vfs_read fs/read_write.c:461 [inline]
 vfs_read+0x143/0x2c0 fs/read_write.c:446
 ksys_read+0xd5/0x1b0 fs/read_write.c:587
 __do_sys_read fs/read_write.c:597 [inline]
 __se_sys_read fs/read_write.c:595 [inline]
 __x64_sys_read+0x4c/0x60 fs/read_write.c:595
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff85fde628 of 4 bytes by task 1301 on cpu 0:
 kvm_check_tsc_unstable arch/x86/kvm/x86.c:1837 [inline]
 kvm_arch_vcpu_load+0x1e5/0x620 arch/x86/kvm/x86.c:3418
 kvm_sched_in+0x8e/0xc0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4234
 __fire_sched_in_preempt_notifiers kernel/sched/core.c:3029 [inline]
 fire_sched_in_preempt_notifiers kernel/sched/core.c:3035 [inline]
 finish_task_switch+0xee/0x260 kernel/sched/core.c:3227
 context_switch kernel/sched/core.c:3387 [inline]
 __schedule+0x319/0x640 kernel/sched/core.c:4069
 preempt_schedule_common+0x37/0x90 kernel/sched/core.c:4217
 preempt_schedule+0x30/0x40 kernel/sched/core.c:4242
 ___preempt_schedule+0x16/0x20 arch/x86/entry/thunk_64.S:50
 vcpu_enter_guest+0x33ec/0x3830 arch/x86/kvm/x86.c:8208
 vcpu_run arch/x86/kvm/x86.c:8291 [inline]
 kvm_arch_vcpu_ioctl_run+0x2a2/0xdc0 arch/x86/kvm/x86.c:8498
 kvm_vcpu_ioctl+0x752/0xa30 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2772
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x991/0xc60 fs/ioctl.c:696
 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:718
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1301 Comm: syz-executor.0 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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