After a partial stream receive, rx_bytes tracks the unread suffix while
buf_used and peer credit still cover the whole packet.
virtio_transport_read_skb() dequeues that packet but passes pkt_len for
both counters, underflowing rx_bytes.

On a connected CID_LOCAL stream with an SK_SKB verdict, a 40-byte read
from a 100-byte packet made SIOCINQ report -40, an empty recv return
ELOOP, and poll report the empty socket readable.  After verdict detach,
receiving 40 bytes wrapped the counter to zero and hid those queued bytes
until one more byte arrived.  The fixed run kept the counter balanced
and exposed all queued data immediately.

Subtract only skb->len minus the VSOCK offset from rx_bytes.  Retain the
full packet length for buf_used and peer credit.

Fixes: 45ca7e9f0730 ("vsock/virtio: fix `rx_bytes` accounting for stream sockets")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Daehyeon Ko <4ncienth@gmail.com>
---
 net/vmw_vsock/virtio_transport_common.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index f225f53ed4bab..1e762a480df49 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1927,6 +1927,7 @@ int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_acto
 	struct sock *sk = sk_vsock(vsk);
 	struct virtio_vsock_hdr *hdr;
 	struct sk_buff *skb;
+	u32 bytes_read;
 	u32 pkt_len;
 	int off = 0;
 	int err;
@@ -1946,7 +1947,8 @@ int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_acto
 		vvs->msg_count--;
 
 	pkt_len = le32_to_cpu(hdr->len);
-	virtio_transport_dec_rx_pkt(vvs, pkt_len, pkt_len);
+	bytes_read = skb->len - VIRTIO_VSOCK_SKB_CB(skb)->offset;
+	virtio_transport_dec_rx_pkt(vvs, bytes_read, pkt_len);
 	spin_unlock_bh(&vvs->rx_lock);
 
 	virtio_transport_send_credit_update(vsk);

base-commit: e23a64eb244356ee47c0620f0722d51bd88db522
-- 
2.55.0