syzbot

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BUG: KCSAN: data-race in free_old_xmit_skbs / virtnet_stats

write to 0xffff888102a416e0 of 8 bytes by interrupt on cpu 1:
 free_old_xmit_skbs+0x14d/0x190 drivers/net/virtio_net.c:1502
 virtnet_poll_tx+0x11a/0x280 drivers/net/virtio_net.c:1619
 __napi_poll+0x65/0x3f0 net/core/dev.c:7023
 napi_poll net/core/dev.c:7090 [inline]
 net_rx_action+0x29e/0x650 net/core/dev.c:7177
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0x37/0x70 kernel/softirq.c:649
 common_interrupt+0x9f/0xc0 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x1e/0x40
 kcsan_setup_watchpoint+0x94/0x420 kernel/kcsan/core.c:443
 __list_add include/linux/list.h:74 [inline]
 list_add_tail include/linux/list.h:102 [inline]
 list_move_tail include/linux/list.h:230 [inline]
 tcp_update_skb_after_send net/ipv4/tcp_output.c:1219 [inline]
 __tcp_transmit_skb+0x150f/0x1840 net/ipv4/tcp_output.c:1411
 tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline]
 tcp_write_xmit+0x1450/0x4460 net/ipv4/tcp_output.c:2680
 __tcp_push_pending_frames+0x68/0x1c0 net/ipv4/tcp_output.c:2864
 tcp_push+0x2d9/0x2f0 net/ipv4/tcp.c:725
 tcp_sendmsg_locked+0x1cb0/0x25a0 net/ipv4/tcp.c:1412
 tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1440
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 sock_write_iter+0x1a3/0x200 net/socket.c:1057
 call_write_iter include/linux/fs.h:2162 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x7f5/0x950 fs/read_write.c:590
 ksys_write+0xd9/0x190 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888102a416e0 of 8 bytes by task 1475 on cpu 0:
 virtnet_stats+0x149/0x350 drivers/net/virtio_net.c:1883
 dev_get_stats+0x65/0x180 net/core/dev.c:10691
 rtnl_fill_stats+0x45/0x320 net/core/rtnetlink.c:1202
 rtnl_fill_ifinfo+0xebf/0x2560 net/core/rtnetlink.c:1774
 rtnl_dump_ifinfo+0x893/0xce0 net/core/rtnetlink.c:2138
 netlink_dump+0x364/0x6b0 net/netlink/af_netlink.c:2270
 netlink_recvmsg+0x486/0x810 net/netlink/af_netlink.c:2004
 ____sys_recvmsg+0x16c/0x320
 ___sys_recvmsg net/socket.c:2670 [inline]
 __sys_recvmsg+0x209/0x3f0 net/socket.c:2700
 __do_sys_recvmsg net/socket.c:2710 [inline]
 __se_sys_recvmsg net/socket.c:2707 [inline]
 __x64_sys_recvmsg+0x42/0x50 net/socket.c:2707
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000012869 -> 0x000000000001286a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1475 Comm: dhcpcd Tainted: G        W         5.16.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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