[PATCH 5.10 036/158] virtio_net: fix memory leak inside XPD_TX with mergeable

[Greg Kroah-Hartman]

From: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>

commit 7a542bee27c6a57e45c33cbbdc963325fd6493af upstream.

When we call xdp_convert_buff_to_frame() to get xdpf, if it returns
NULL, we should check if xdp_page was allocated by xdp_linearize_page().
If it is newly allocated, it should be freed here alone. Just like any
other "goto err_xdp".

Fixes: 44fa2dbd4759 ("xdp: transition into using xdp_frame for ndo_xdp_xmit")
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/virtio_net.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -968,8 +968,11 @@ static struct sk_buff *receive_mergeable
 		case XDP_TX:
 			stats->xdp_tx++;
 			xdpf = xdp_convert_buff_to_frame(&xdp);
-			if (unlikely(!xdpf))
+			if (unlikely(!xdpf)) {
+				if (unlikely(xdp_page != page))
+					put_page(xdp_page);
 				goto err_xdp;
+			}
 			err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
 			if (unlikely(err < 0)) {
 				trace_xdp_exception(vi->dev, xdp_prog, act);