Commit 27f575836cfe for kernel
commit 27f575836cfebbf872dec020428742b10650a955
Author: Théo Lebrun <theo.lebrun@bootlin.com>
Date: Thu Jul 2 17:37:02 2026 +0200
net: macb: drop in-flight Tx SKBs on close
The MACB driver has since forever leaked the outgoing SKBs that
have not yet been marked as completed. They live in queue->tx_skb
which gets freed without remorse nor checking.
macb_free_consistent() gets called in a few codepaths, but only close will
trigger the added expressions. In macb_open() and macb_alloc_consistent()
failure cases, queues' tx_skb just got allocated and are empty.
Fixes: 89e5785fc8a6 ("[PATCH] Atmel MACB ethernet driver")
Cc: stable@vger.kernel.org
Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://patch.msgid.link/20260702-macb-drop-tx-v4-1-1c833eebdbc8@bootlin.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index fd282a1700fb..d394f1f43b68 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -2668,8 +2668,25 @@ static void macb_free_consistent(struct macb *bp)
dma_free_coherent(dev, size, bp->queues[0].rx_ring, bp->queues[0].rx_ring_dma);
for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
- kfree(queue->tx_skb);
- queue->tx_skb = NULL;
+ if (queue->tx_skb) {
+ unsigned int dropped = 0, tail;
+
+ for (tail = queue->tx_tail; tail != queue->tx_head;
+ tail++) {
+ if (macb_tx_skb(queue, tail)->skb)
+ dropped++;
+ macb_tx_unmap(bp, macb_tx_skb(queue, tail), 0);
+ }
+
+ queue->stats.tx_dropped += dropped;
+ bp->dev->stats.tx_dropped += dropped;
+
+ kfree(queue->tx_skb);
+ queue->tx_skb = NULL;
+ }
+
+ queue->tx_head = 0;
+ queue->tx_tail = 0;
queue->tx_ring = NULL;
queue->rx_ring = NULL;
}