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BUG: KCSAN: data-race in __mod_timer / timer_clear_idle

write to 0xffff888237d1b665 of 1 bytes by task 0 on cpu 1:
 timer_clear_idle+0x1e/0x30 kernel/time/timer.c:1713
 tick_nohz_restart_sched_tick kernel/time/tick-sched.c:916 [inline]
 __tick_nohz_idle_restart_tick+0x20/0x180 kernel/time/tick-sched.c:1210
 tick_nohz_idle_exit+0x104/0x220 kernel/time/tick-sched.c:1251
 do_idle+0x1f6/0x230 kernel/sched/idle.c:313
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:397
 secondary_startup_64_no_verify+0xb0/0xbb

read to 0xffff888237d1b665 of 1 bytes by interrupt on cpu 0:
 trigger_dyntick_cpu kernel/time/timer.c:568 [inline]
 enqueue_timer kernel/time/timer.c:599 [inline]
 __mod_timer+0x906/0xbe0 kernel/time/timer.c:1058
 mod_timer+0x1b/0x20 kernel/time/timer.c:1106
 sk_reset_timer+0x1f/0xa0 net/core/sock.c:2954
 tcp_send_delayed_ack+0x23e/0x250 net/ipv4/tcp_output.c:3932
 __tcp_ack_snd_check+0x2f9/0x510 net/ipv4/tcp_input.c:5419
 tcp_rcv_established+0x1196/0x12a0 net/ipv4/tcp_input.c:5848
 tcp_v4_do_rcv+0x278/0x4a0 net/ipv4/tcp_ipv4.c:1679
 tcp_v4_rcv+0x2156/0x23e0 net/ipv4/tcp_ipv4.c:2062
 ip_protocol_deliver_rcu+0x20e/0x410 net/ipv4/ip_input.c:204
 ip_local_deliver_finish net/ipv4/ip_input.c:231 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_local_deliver+0x1d1/0x290 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:458 [inline]
 ip_sublist_rcv_finish net/ipv4/ip_input.c:551 [inline]
 ip_list_rcv_finish net/ipv4/ip_input.c:601 [inline]
 ip_sublist_rcv+0x3e4/0x4b0 net/ipv4/ip_input.c:609
 ip_list_rcv+0x262/0x290 net/ipv4/ip_input.c:644
 __netif_receive_skb_list_ptype net/core/dev.c:5427 [inline]
 __netif_receive_skb_list_core+0x34b/0x450 net/core/dev.c:5475
 __netif_receive_skb_list+0x262/0x2e0 net/core/dev.c:5527
 netif_receive_skb_list_internal+0xd5/0x330 net/core/dev.c:5637
 gro_normal_list net/core/dev.c:5791 [inline]
 napi_complete_done+0x1b2/0x3b0 net/core/dev.c:6494
 virtqueue_napi_complete+0x28/0x80 drivers/net/virtio_net.c:334
 virtnet_poll+0x68c/0x7c0 drivers/net/virtio_net.c:1459
 __napi_poll+0x65/0x3a0 net/core/dev.c:6913
 napi_poll net/core/dev.c:6980 [inline]
 net_rx_action+0x29f/0x680 net/core/dev.c:7067
 __do_softirq+0x12c/0x275 kernel/softirq.c:345
 invoke_softirq kernel/softirq.c:221 [inline]
 __irq_exit_rcu+0xaa/0xb0 kernel/softirq.c:422
 common_interrupt+0x78/0x90 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:623
 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
 acpi_idle_do_entry drivers/acpi/processor_idle.c:517 [inline]
 acpi_idle_enter+0x25b/0x2e0 drivers/acpi/processor_idle.c:652
 cpuidle_enter_state+0x2b6/0x750 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x3c/0x60 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:158 [inline]
 cpuidle_idle_call kernel/sched/idle.c:239 [inline]
 do_idle+0x193/0x230 kernel/sched/idle.c:300
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:397
 rest_init+0xc9/0xd0 init/main.c:721
 arch_call_rest_init+0xa/0xb
 start_kernel+0x59e/0x623 init/main.c:1064
 secondary_startup_64_no_verify+0xb0/0xbb

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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