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From:   Liang Chen <liangchen.linux@gmail.com>
To:     jasowang@redhat.com, mst@redhat.com
Cc:     virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, xuanzhuo@linux.alibaba.com,
        kuba@kernel.org, edumazet@google.com, davem@davemloft.net,
        pabeni@redhat.com, alexander.duyck@gmail.com,
        Liang Chen <liangchen.linux@gmail.com>
Subject: [PATCH net-next 1/5] virtio_net: Fix an unsafe reference to the page chain
Date:   Fri, 26 May 2023 13:46:17 +0800
Message-Id: <20230526054621.18371-1-liangchen.linux@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

"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 <liangchen.linux@gmail.com>
---
 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