linux-kernel - [PATCH] rtl818x_pci: Fix potential memory leaks in rtl8180_init_rx

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Message-ID: <20251113165851.39054-1-nihaal@cse.iitm.ac.in>
Date: Thu, 13 Nov 2025 22:28:49 +0530
From: Abdun Nihaal <nihaal@....iitm.ac.in>
To: linux-wireless@...r.kernel.org
Cc: Abdun Nihaal <nihaal@....iitm.ac.in>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] rtl818x_pci: Fix potential memory leaks in rtl8180_init_rx_ring()

In rtl8180_init_rx_ring(), memory is allocated for skb packets and DMA
allocations in a loop. When an allocation fails, the previously
successful allocations are not freed on exit.

Fixes: f653211197f3 ("Add rtl8180 wireless driver")
Signed-off-by: Abdun Nihaal <nihaal@....iitm.ac.in>
---
Compile tested only.

 .../wireless/realtek/rtl818x/rtl8180/dev.c    | 24 ++++++++++++-------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c b/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c
index 2905baea6239..898611ccb400 100644
--- a/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c
+++ b/drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c
@@ -1023,11 +1023,8 @@ static int rtl8180_init_rx_ring(struct ieee80211_hw *dev)
 		dma_addr_t *mapping;
 		entry = priv->rx_ring + priv->rx_ring_sz*i;
 		if (!skb) {
-			dma_free_coherent(&priv->pdev->dev,
-					  priv->rx_ring_sz * 32,
-					  priv->rx_ring, priv->rx_ring_dma);
 			wiphy_err(dev->wiphy, "Cannot allocate RX skb\n");
-			return -ENOMEM;
+			goto error;
 		}
 		priv->rx_buf[i] = skb;
 		mapping = (dma_addr_t *)skb->cb;
@@ -1037,11 +1034,9 @@ static int rtl8180_init_rx_ring(struct ieee80211_hw *dev)
 
 		if (dma_mapping_error(&priv->pdev->dev, *mapping)) {
 			kfree_skb(skb);
-			dma_free_coherent(&priv->pdev->dev,
-					  priv->rx_ring_sz * 32,
-					  priv->rx_ring, priv->rx_ring_dma);
+			priv->rx_buf[i] = NULL;
 			wiphy_err(dev->wiphy, "Cannot map DMA for RX skb\n");
-			return -ENOMEM;
+			goto error;
 		}
 
 		entry->rx_buf = cpu_to_le32(*mapping);
@@ -1050,6 +1045,19 @@ static int rtl8180_init_rx_ring(struct ieee80211_hw *dev)
 	}
 	entry->flags |= cpu_to_le32(RTL818X_RX_DESC_FLAG_EOR);
 	return 0;
+error:
+	while (i--) {
+		struct sk_buff *skb = priv->rx_buf[i];
+		priv->rx_buf[i] = NULL;
+		dma_unmap_single(&priv->pdev->dev, *((dma_addr_t *)skb->cb),
+				 MAX_RX_SIZE, DMA_FROM_DEVICE);
+		kfree_skb(skb);
+	}
+	dma_free_coherent(&priv->pdev->dev,
+			  priv->rx_ring_sz * 32,
+			  priv->rx_ring, priv->rx_ring_dma);
+	priv->rx_ring = NULL;
+	return -ENOMEM;
 }
 
 static void rtl8180_free_rx_ring(struct ieee80211_hw *dev)
-- 
2.43.0