FAILED: patch "[PATCH] virtio_net: fix memory leak inside XPD_TX with mergeable" failed to apply to 4.19-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7a542bee27c6a57e45c33cbbdc963325fd6493af Mon Sep 17 00:00:00 2001
From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Date: Thu, 4 Aug 2022 14:32:48 +0800
Subject: [PATCH] virtio_net: fix memory leak inside XPD_TX with mergeable

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@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ec8e1b3108c3..3b3eebad3977 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1057,8 +1057,11 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 		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)) {
 				xdp_return_frame_rx_napi(xdpf);