==================================================================
BUG: KCSAN: data-race in virtqueue_enable_cb_delayed / virtqueue_enable_cb_prepare

write to 0xffff8881292cf370 of 2 bytes by interrupt on cpu 1:
 virtqueue_enable_cb_delayed_split drivers/virtio/virtio_ring.c:795 [inline]
 virtqueue_enable_cb_delayed+0x219/0x4d0 drivers/virtio/virtio_ring.c:2006
 start_xmit+0xb0f/0xbe0 drivers/net/virtio_net.c:1565
 __netdev_start_xmit include/linux/netdevice.h:4413 [inline]
 netdev_start_xmit include/linux/netdevice.h:4427 [inline]
 xmit_one net/core/dev.c:3199 [inline]
 dev_hard_start_xmit+0xef/0x430 net/core/dev.c:3215
 sch_direct_xmit+0x2b3/0x900 net/sched/sch_generic.c:313
 __dev_xmit_skb net/core/dev.c:3400 [inline]
 __dev_queue_xmit+0x19a3/0x1b40 net/core/dev.c:3761
 dev_queue_xmit+0x21/0x30 net/core/dev.c:3825
 neigh_hh_output include/net/neighbour.h:500 [inline]
 neigh_output include/net/neighbour.h:509 [inline]
 ip_finish_output2+0x836/0xe40 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:308 [inline]
 __ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290
 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip_output+0xdf/0x210 net/ipv4/ip_output.c:432
 dst_output include/net/dst.h:436 [inline]
 ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125
 __ip_queue_xmit+0x3a8/0xa40 net/ipv4/ip_output.c:532
 ip_queue_xmit+0x45/0x60 include/net/ip.h:237
 __tcp_transmit_skb+0xe81/0x1d60 net/ipv4/tcp_output.c:1169
 __tcp_send_ack+0x246/0x300 net/ipv4/tcp_output.c:3696
 tcp_send_ack+0x34/0x40 net/ipv4/tcp_output.c:3702
 __tcp_ack_snd_check+0xd9/0x4f0 net/ipv4/tcp_input.c:5243
 tcp_rcv_established+0xce9/0xf50 net/ipv4/tcp_input.c:5674
 tcp_v4_do_rcv+0x3b5/0x520 net/ipv4/tcp_ipv4.c:1564
 tcp_v4_rcv+0x19ec/0x1bd0 net/ipv4/tcp_ipv4.c:1945
 ip_protocol_deliver_rcu+0x4d/0x420 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:4929
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5043
 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5133
 napi_skb_finish net/core/dev.c:5596 [inline]
 napi_gro_receive+0x28f/0x330 net/core/dev.c:5629
 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:6311 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6379
 __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
 native_safe_halt+0xe/0x10 arch/x86/kernel/paravirt.c:71
 arch_cpu_idle+0x1f/0x30 arch/x86/kernel/process.c:571
 default_idle_call+0x1e/0x40 kernel/sched/idle.c:94
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x1af/0x280 kernel/sched/idle.c:263
 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355
 start_secondary+0x208/0x260 arch/x86/kernel/smpboot.c:264
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241

read to 0xffff8881292cf370 of 2 bytes by interrupt on cpu 0:
 virtqueue_enable_cb_prepare_split drivers/virtio/virtio_ring.c:761 [inline]
 virtqueue_enable_cb_prepare+0x142/0x2b0 drivers/virtio/virtio_ring.c:1946
 virtqueue_napi_complete+0x2c/0xa0 drivers/net/virtio_net.c:328
 virtnet_poll_tx+0x15f/0x1d0 drivers/net/virtio_net.c:1496
 napi_poll net/core/dev.c:6311 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6379
 __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
 arch_local_irq_enable arch/x86/include/asm/paravirt.h:766 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
 _raw_spin_unlock_irq+0x4e/0x80 kernel/locking/spinlock.c:199
 spin_unlock_irq include/linux/spinlock.h:388 [inline]
 process_one_work+0x3b5/0x890 kernel/workqueue.c:2242
 worker_thread+0xa0/0x800 kernel/workqueue.c:2415
 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: 0 PID: 8072 Comm: kworker/0:3 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ceph-msgr ceph_con_workfn
==================================================================