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BUG: KCSAN: data-race in ktime_get_with_offset / timekeeping_advance

write to 0xffffffff86040b08 of 280 bytes by interrupt on cpu 0:
 timekeeping_advance+0x893/0xd80 include/linux/string.h:378
 update_wall_time+0x19/0x20 kernel/time/timekeeping.c:2137
 tick_do_update_jiffies64+0x1ae/0x260 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+0x288/0x600 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
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline]
 __kcsan_setup_watchpoint+0x268/0x4a0 kernel/kcsan/core.c:424
 __tsan_read8 kernel/kcsan/kcsan.c:36 [inline]
 __tsan_read8+0x2c/0x30 kernel/kcsan/kcsan.c:36
 ipt_do_table+0xac/0xe60 net/ipv4/netfilter/ip_tables.c:245
 iptable_mangle_hook+0x7a/0x260 net/ipv4/netfilter/iptable_mangle.c:82
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x83/0x160 net/netfilter/core.c:512

read to 0xffffffff86040b18 of 8 bytes by interrupt on cpu 1:
 timekeeping_get_delta kernel/time/timekeeping.c:270 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:374 [inline]
 ktime_get_with_offset+0xe7/0x230 kernel/time/timekeeping.c:802
 ktime_get_real include/linux/timekeeping.h:79 [inline]
 __net_timestamp include/linux/skbuff.h:3658 [inline]
 netif_receive_skb_internal+0x13e/0x190 net/core/dev.c:5196
 napi_skb_finish net/core/dev.c:5677 [inline]
 napi_gro_receive+0x28f/0x330 net/core/dev.c:5710
 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061
 virtnet_receive drivers/net/virtio_net.c:1323 [inline]
 virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428
 napi_poll net/core/dev.c:6392 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6460
 __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]
 do_IRQ+0xa6/0x180 arch/x86/kernel/irq.c:263
 ret_from_intr+0x0/0x19
 check_kcov_mode kernel/kcov.c:68 [inline]
 __sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:102
 vm_normal_page+0x24/0x220 mm/memory.c:577
 copy_one_pte mm/memory.c:770 [inline]
 copy_pte_range mm/memory.c:823 [inline]
 copy_pmd_range mm/memory.c:874 [inline]
 copy_pud_range mm/memory.c:908 [inline]
 copy_p4d_range mm/memory.c:930 [inline]
 copy_page_range+0xc63/0x1a80 mm/memory.c:992

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7388 Comm: syz-executor.3 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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