syzbot

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BUG: KCSAN: data-race in virtqueue_get_buf_ctx / vring_interrupt

read-write to 0xffff8881031aab50 of 2 bytes by task 3061 on cpu 1:
 virtqueue_get_buf_ctx_split drivers/virtio/virtio_ring.c:836 [inline]
 virtqueue_get_buf_ctx+0x3d1/0x5b0 drivers/virtio/virtio_ring.c:2327
 virtqueue_get_buf+0x1f/0x30 drivers/virtio/virtio_ring.c:2333
 free_old_xmit_skbs+0x4f/0x1f0 drivers/net/virtio_net.c:559
 start_xmit+0xfa/0xae0 drivers/net/virtio_net.c:2042
 __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
 netdev_start_xmit include/linux/netdevice.h:4932 [inline]
 xmit_one net/core/dev.c:3578 [inline]
 dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3594
 sch_direct_xmit+0x1b0/0x570 net/sched/sch_generic.c:342
 __dev_xmit_skb net/core/dev.c:3805 [inline]
 __dev_queue_xmit+0xe5f/0x1d10 net/core/dev.c:4210
 dev_queue_xmit include/linux/netdevice.h:3088 [inline]
 neigh_hh_output include/net/neighbour.h:528 [inline]
 neigh_output include/net/neighbour.h:542 [inline]
 ip_finish_output2+0x700/0x840 net/ipv4/ip_output.c:229
 ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:317
 NF_HOOK_COND include/linux/netfilter.h:292 [inline]
 ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:431
 dst_output include/net/dst.h:458 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 __ip_queue_xmit+0xa4d/0xa70 net/ipv4/ip_output.c:533
 ip_queue_xmit+0x38/0x40 net/ipv4/ip_output.c:547
 __tcp_transmit_skb+0x1194/0x16e0 net/ipv4/tcp_output.c:1399
 tcp_transmit_skb net/ipv4/tcp_output.c:1417 [inline]
 tcp_write_xmit+0x13ff/0x2fd0 net/ipv4/tcp_output.c:2693
 __tcp_push_pending_frames+0x6a/0x1a0 net/ipv4/tcp_output.c:2877
 tcp_push+0x320/0x330 net/ipv4/tcp.c:733
 tcp_sendmsg_locked+0x1cf8/0x2120 net/ipv4/tcp.c:1459
 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1487
 inet_sendmsg+0x63/0x80 net/ipv4/af_inet.c:827
 sock_sendmsg_nosec net/socket.c:724 [inline]
 sock_sendmsg net/socket.c:747 [inline]
 sock_write_iter+0x1aa/0x230 net/socket.c:1140
 call_write_iter include/linux/fs.h:1868 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x47b/0x780 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881031aab50 of 2 bytes by interrupt on cpu 0:
 more_used_split drivers/virtio/virtio_ring.c:789 [inline]
 more_used drivers/virtio/virtio_ring.c:2465 [inline]
 vring_interrupt+0x9d/0x170 drivers/virtio/virtio_ring.c:2480
 __handle_irq_event_percpu+0x91/0x490 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0x64/0xf0 kernel/irq/handle.c:210
 handle_edge_irq+0x167/0x590 kernel/irq/chip.c:819
 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
 handle_irq arch/x86/kernel/irq.c:231 [inline]
 __common_interrupt+0x3c/0xb0 arch/x86/kernel/irq.c:250
 common_interrupt+0x7a/0x90 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636
 __tsan_read8+0x0/0x180 kernel/kcsan/core.c:753
 kernfs_dir_pos+0x45/0x1f0 fs/kernfs/dir.c:1770
 kernfs_dir_next_pos fs/kernfs/dir.c:1802 [inline]
 kernfs_fop_readdir+0x37a/0x4a0 fs/kernfs/dir.c:1834
 iterate_dir+0x16c/0x390
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x88/0x1a0 fs/readdir.c:354
 __x64_sys_getdents64+0x43/0x50 fs/readdir.c:354
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x4af9 -> 0x4afa

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2745 Comm: udevd Not tainted 6.4.0-rc5-syzkaller-00245-g64569520920a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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