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BUG: KCSAN: data-race in wg_packet_send_staged_packets / wg_packet_send_staged_packets

write to 0xffff88812b14fa08 of 4 bytes by interrupt on cpu 1:
 wg_cpumask_next_online drivers/net/wireguard/queueing.h:134 [inline]
 wg_queue_enqueue_per_device_and_peer drivers/net/wireguard/queueing.h:153 [inline]
 wg_packet_create_data drivers/net/wireguard/send.c:326 [inline]
 wg_packet_send_staged_packets+0x5d5/0x990 drivers/net/wireguard/send.c:396
 wg_packet_send_keepalive+0xea/0x100 drivers/net/wireguard/send.c:239
 wg_expired_send_persistent_keepalive+0x38/0x50 drivers/net/wireguard/timers.c:141
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1417
 expire_timers+0x116/0x260 kernel/time/timer.c:1462
 __run_timers+0x338/0x3d0 kernel/time/timer.c:1731
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1744
 __do_softirq+0x13c/0x2c3 kernel/softirq.c:343
 asm_call_irq_on_stack+0xf/0x20
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x32/0x40 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:226 [inline]
 __irq_exit_rcu+0xb4/0xc0 kernel/softirq.c:420
 sysvec_apic_timer_interrupt+0x74/0x90 arch/x86/kernel/apic/apic.c:1096
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
 native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:110 [inline]
 acpi_idle_do_entry drivers/acpi/processor_idle.c:516 [inline]
 acpi_idle_enter+0x25b/0x2e0 drivers/acpi/processor_idle.c:647
 cpuidle_enter_state+0x2bd/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:299
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:396
 secondary_startup_64_no_verify+0xb0/0xbb

read to 0xffff88812b14fa08 of 4 bytes by interrupt on cpu 0:
 wg_cpumask_next_online drivers/net/wireguard/queueing.h:130 [inline]
 wg_queue_enqueue_per_device_and_peer drivers/net/wireguard/queueing.h:153 [inline]
 wg_packet_create_data drivers/net/wireguard/send.c:326 [inline]
 wg_packet_send_staged_packets+0x592/0x990 drivers/net/wireguard/send.c:396
 wg_packet_send_keepalive+0xea/0x100 drivers/net/wireguard/send.c:239
 wg_expired_send_persistent_keepalive+0x38/0x50 drivers/net/wireguard/timers.c:141
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1417
 expire_timers+0x116/0x260 kernel/time/timer.c:1462
 __run_timers+0x338/0x3d0 kernel/time/timer.c:1731
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1744
 __do_softirq+0x13c/0x2c3 kernel/softirq.c:343
 asm_call_irq_on_stack+0xf/0x20
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x32/0x40 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:226 [inline]
 __irq_exit_rcu+0xb4/0xc0 kernel/softirq.c:420
 sysvec_apic_timer_interrupt+0x74/0x90 arch/x86/kernel/apic/apic.c:1096
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
 native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:110 [inline]
 acpi_idle_do_entry drivers/acpi/processor_idle.c:516 [inline]
 acpi_idle_enter+0x25b/0x2e0 drivers/acpi/processor_idle.c:647
 cpuidle_enter_state+0x2bd/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:299
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:396
 rest_init+0xd7/0xe0 init/main.c:720
 arch_call_rest_init+0xa/0xb
 start_kernel+0x59b/0x620 init/main.c:1061
 secondary_startup_64_no_verify+0xb0/0xbb

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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