On Fri, May 08, 2026 at 06:44:10PM +0200, Stefano Garzarella wrote: > From: Stefano Garzarella <[email protected]> > > virtio_transport_build_skb() builds a new skb to be delivered to the > vsockmon tap device. To build the new skb, it uses the original skb > data length as payload length, but as the comment notes, the original > packet stored in the skb may have been split in multiple packets, so we > need to use the length in the header, which is correctly updated before > the packet is delivered to the tap, and the offset for the data. > > This was also similar to what we did before commit 71dc9ec9ac7d > ("virtio/vsock: replace virtio_vsock_pkt with sk_buff") where we probably > missed something during the skb conversion. > > Also update the comment above, which was left stale by the skb > conversion and still mentioned a buffer pointer that no longer exists. > > Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff") > Signed-off-by: Stefano Garzarella <[email protected]> > --- > net/vmw_vsock/virtio_transport_common.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/net/vmw_vsock/virtio_transport_common.c > b/net/vmw_vsock/virtio_transport_common.c > index 9b8014516f4f..a678d5d75704 100644 > --- a/net/vmw_vsock/virtio_transport_common.c > +++ b/net/vmw_vsock/virtio_transport_common.c > @@ -166,12 +166,12 @@ static struct sk_buff *virtio_transport_build_skb(void > *opaque) > struct sk_buff *skb; > size_t payload_len; > > - /* A packet could be split to fit the RX buffer, so we can retrieve > - * the payload length from the header and the buffer pointer taking > - * care of the offset in the original packet. > + /* A packet could be split to fit the RX buffer, so we use > + * the payload length from the header, which has been updated > + * by the sender to reflect the fragment size. > */ > pkt_hdr = virtio_vsock_hdr(pkt); > - payload_len = pkt->len; > + payload_len = le32_to_cpu(pkt_hdr->len); > > skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len, > GFP_ATOMIC); > @@ -219,7 +219,8 @@ static struct sk_buff *virtio_transport_build_skb(void > *opaque) > > virtio_transport_copy_nonlinear_skb(pkt, data, > payload_len); > } else { > - skb_put_data(skb, pkt->data, payload_len); > + skb_put_data(skb, pkt->data + > VIRTIO_VSOCK_SKB_CB(pkt)->offset, > + payload_len); > } > } > > -- > 2.54.0 >
Reviewed-by: Bobby Eshleman <[email protected]>
