[PATCH 6.6 128/160] net: ftgmac100: fix ring allocation unwind on open failure

Greg Kroah-Hartman
2026-04-08T18:25:55Z

From: Yufan Chen <yufan.chen@linux.dev>

commit c0fd0fe745f5e8c568d898cd1513d0083e46204a upstream.

ftgmac100_alloc_rings() allocates rx_skbs, tx_skbs, rxdes, txdes, and
rx_scratch in stages. On intermediate failures it returned -ENOMEM
directly, leaking resources allocated earlier in the function.

Rework the failure path to use staged local unwind labels and free
allocated resources in reverse order before returning -ENOMEM. This
matches common netdev allocation cleanup style.

Fixes: d72e01a0430f ("ftgmac100: Use a scratch buffer for failed RX allocations")
Cc: stable@vger.kernel.org
Signed-off-by: Yufan Chen <yufan.chen@linux.dev>
Link: https://patch.msgid.link/20260328163257.60836-1-yufan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/faraday/ftgmac100.c | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -934,19 +934,19 @@ static int ftgmac100_alloc_rings(struct
priv->tx_skbs = kcalloc(MAX_TX_QUEUE_ENTRIES, sizeof(void *),
GFP_KERNEL);
if (!priv->tx_skbs)
- return -ENOMEM;
+ goto err_free_rx_skbs;

/* Allocate descriptors */
priv->rxdes = dma_alloc_coherent(priv->dev,
MAX_RX_QUEUE_ENTRIES * sizeof(struct ftgmac100_rxdes),
&priv->rxdes_dma, GFP_KERNEL);
if (!priv->rxdes)
- return -ENOMEM;
+ goto err_free_tx_skbs;
priv->txdes = dma_alloc_coherent(priv->dev,
MAX_TX_QUEUE_ENTRIES * sizeof(struct ftgmac100_txdes),
&priv->txdes_dma, GFP_KERNEL);
if (!priv->txdes)
- return -ENOMEM;
+ goto err_free_rxdes;

/* Allocate scratch packet buffer */
priv->rx_scratch = dma_alloc_coherent(priv->dev,
@@ -954,9 +954,29 @@ static int ftgmac100_alloc_rings(struct
&priv->rx_scratch_dma,
GFP_KERNEL);
if (!priv->rx_scratch)
- return -ENOMEM;
+ goto err_free_txdes;

return 0;
+
+err_free_txdes:
+ dma_free_coherent(priv->dev,
+ MAX_TX_QUEUE_ENTRIES *
+ sizeof(struct ftgmac100_txdes),
+ priv->txdes, priv->txdes_dma);
+ priv->txdes = NULL;
+err_free_rxdes:
+ dma_free_coherent(priv->dev,
+ MAX_RX_QUEUE_ENTRIES *
+ sizeof(struct ftgmac100_rxdes),
+ priv->rxdes, priv->rxdes_dma);
+ priv->rxdes = NULL;
+err_free_tx_skbs:
+ kfree(priv->tx_skbs);
+ priv->tx_skbs = NULL;
+err_free_rx_skbs:
+ kfree(priv->rx_skbs);
+ priv->rx_skbs = NULL;
+ return -ENOMEM;
}

static void ftgmac100_init_rings(struct ftgmac100 *priv)