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BUG: KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed

write to 0xffff88821aa54130 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:4510 [inline]
 netdev_start_xmit include/linux/netdevice.h:4524 [inline]
 xmit_one net/core/dev.c:3470 [inline]
 dev_hard_start_xmit+0xef/0x430 net/core/dev.c:3486
 sch_direct_xmit+0x2b3/0x900 net/sched/sch_generic.c:313
 __dev_xmit_skb net/core/dev.c:3671 [inline]
 __dev_queue_xmit+0x13e2/0x1ba0 net/core/dev.c:4032
 dev_queue_xmit+0x21/0x30 net/core/dev.c:4096
 neigh_hh_output include/net/neighbour.h:499 [inline]
 neigh_output include/net/neighbour.h:508 [inline]
 ip_finish_output2+0x89b/0xea0 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:306 [inline]
 __ip_finish_output+0x23a/0x4b0 net/ipv4/ip_output.c:288
 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0xfe/0x230 net/ipv4/ip_output.c:430
 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:530
 ip_queue_xmit+0x45/0x60 include/net/ip.h:237
 __tcp_transmit_skb+0xea3/0x1df0 net/ipv4/tcp_output.c:1234
 __tcp_send_ack+0x246/0x300 net/ipv4/tcp_output.c:3771
 tcp_send_ack+0x34/0x40 net/ipv4/tcp_output.c:3777
 __tcp_ack_snd_check+0xd9/0x580 net/ipv4/tcp_input.c:5263
 tcp_ack_snd_check net/ipv4/tcp_input.c:5309 [inline]
 tcp_rcv_established+0x750/0xf50 net/ipv4/tcp_input.c:5730
 tcp_v4_do_rcv+0x3b5/0x520 net/ipv4/tcp_ipv4.c:1619
 tcp_v4_rcv+0x1c30/0x1e20 net/ipv4/tcp_ipv4.c:2001
 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:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_sublist_rcv_finish+0xf8/0x140 net/ipv4/ip_input.c:549
 ip_list_rcv_finish net/ipv4/ip_input.c:599 [inline]
 ip_sublist_rcv+0x418/0x550 net/ipv4/ip_input.c:607
 ip_list_rcv+0x2f5/0x322 net/ipv4/ip_input.c:642
 __netif_receive_skb_list_ptype net/core/dev.c:5241 [inline]
 __netif_receive_skb_list_ptype net/core/dev.c:5230 [inline]
 __netif_receive_skb_list_core+0x350/0x5c0 net/core/dev.c:5289
 __netif_receive_skb_list net/core/dev.c:5341 [inline]
 netif_receive_skb_list_internal+0x5d8/0x830 net/core/dev.c:5436
 gro_normal_list.part.0+0x3a/0xb0 net/core/dev.c:5547
 gro_normal_list net/core/dev.c:6280 [inline]
 napi_complete_done+0x1df/0x3c0 net/core/dev.c:6268
 virtqueue_napi_complete+0x3a/0xa0 drivers/net/virtio_net.c:329
 virtnet_poll+0x7a6/0x7d0 drivers/net/virtio_net.c:1432
 napi_poll net/core/dev.c:6582 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6650
 __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:546 [inline]
 do_IRQ+0x81/0x130 arch/x86/kernel/irq.c:263
 ret_from_intr+0x0/0x21
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irqrestore+0x51/0x80 kernel/locking/spinlock.c:191
 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline]
 snd_rawmidi_transmit+0xad/0xd0 sound/core/rawmidi.c:1295
 snd_vmidi_output_work+0xb3/0x200 sound/core/seq/seq_virmidi.c:143
 process_one_work+0x413/0x8f0 kernel/workqueue.c:2264
 worker_thread+0xa0/0x800 kernel/workqueue.c:2410
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff88821aa54130 of 2 bytes by interrupt on cpu 0:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:740 [inline]
 virtqueue_disable_cb+0xbc/0x130 drivers/virtio/virtio_ring.c:1925
 virtqueue_napi_schedule+0x52/0x60 drivers/net/virtio_net.c:318
 skb_xmit_done+0xac/0x110 drivers/net/virtio_net.c:346
 vring_interrupt drivers/virtio/virtio_ring.c:2046 [inline]
 vring_interrupt+0x1a1/0x1c0 drivers/virtio/virtio_ring.c:2032
 __handle_irq_event_percpu+0x9a/0x430 kernel/irq/handle.c:149
 handle_irq_event_percpu+0x4b/0xe0 kernel/irq/handle.c:189
 handle_irq_event+0x85/0xca kernel/irq/handle.c:206
 handle_edge_irq+0x1a4/0x4a0 kernel/irq/chip.c:830
 generic_handle_irq_desc include/linux/irqdesc.h:156 [inline]
 do_IRQ+0x7c/0x130 arch/x86/kernel/irq.c:250
 ret_from_intr+0x0/0x21
 __tsan_unaligned_write8+0x7/0x110 kernel/kcsan/core.c:686
 __do_sys_wait4+0xea/0x100 kernel/exit.c:1629
 __se_sys_wait4 kernel/exit.c:1625 [inline]
 __x64_sys_wait4+0x5e/0x80 kernel/exit.c:1625
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7967 Comm: syz-executor.5 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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