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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
 ifname_compare_aligned include/linux/netfilter/x_tables.h:411 [inline]
 ip_packet_match net/ipv4/netfilter/ip_tables.c:64 [inline]
 ipt_do_table+0x46f/0xe60 net/ipv4/netfilter/ip_tables.c:284
 ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:56 [inline]
 iptable_mangle_hook+0x132/0x260 net/ipv4/netfilter/iptable_mangle.c:81
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x83/0x160 net/netfilter/core.c:512

read to 0xffffffff86040b28 of 8 bytes by interrupt on cpu 1:
 timekeeping_delta_to_ns kernel/time/timekeeping.c:363 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:375 [inline]
 ktime_get_with_offset+0x136/0x230 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
 run_ksoftirqd+0x46/0x60 kernel/softirq.c:603
 smpboot_thread_fn+0x37d/0x4a0 kernel/smpboot.c:165
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16 Comm: ksoftirqd/1 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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