Subject: [PATCH net-next 1/5] virtio_net: Fix an unsafe reference to the page chain

From: Liang Chen <[email-masked]>
Date: Fri, 26 May 2023 13:46:17 +0800

"private" of buffer page is currently used for big mode to chain pages.
But in mergeable mode, that offset of page could mean something else,
e.g. when page_pool page is used instead. So excluding mergeable mode to
avoid such a problem.

Signed-off-by: Liang Chen <[email-masked]>
---
 drivers/net/virtio_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5a7f7a76b920..c5dca0d92e64 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -497,7 +497,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 			return NULL;
 
 		page = (struct page *)page->private;
-		if (page)
+		if (!vi->mergeable_rx_bufs && page)
 			give_pages(rq, page);
 		goto ok;
 	}
-- 
2.31.1