[PATCH] net: mvpp2: free pending TX timestamp skbs when the port is stopped

[Wentao Liang]

mvpp2_tx_hw_tstamp() takes an extra reference on skbs that need a TX
timestamp and stores them in port->tx_hwtstamp_queue[]. The reference is
dropped by mvpp2_isr_handle_ptp_queue() when the hardware reports the
timestamp. Nothing drains the queues when the port is stopped, so skbs
still waiting for a timestamp keep their reference until their queue
slot is reused, and are leaked for good when the port is removed.

Free the queued skbs in mvpp2_stop(), after the interrupts have been
released.

Fixes: f5015a594c50 ("net: mvpp2: ptp: add support for transmit timestamping")
Cc: stable@xxxxxxxxxxxxxxx
Assisted-by: DeepSeek-V4.1-Flash and OpenAI Codex
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 317af54369cf..fc020b8c8830 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -3419,6 +3419,22 @@ static void mvpp2_isr_handle_ptp(struct mvpp2_port *port)
 		mvpp2_isr_handle_ptp_queue(port, 1);
 }
 
+static void mvpp2_tx_hwtstamp_flush(struct mvpp2_port *port)
+{
+	struct mvpp2_hwtstamp_queue *queue;
+	int nq, i;
+
+	for (nq = 0; nq < ARRAY_SIZE(port->tx_hwtstamp_queue); nq++) {
+		queue = &port->tx_hwtstamp_queue[nq];
+		for (i = 0; i < ARRAY_SIZE(queue->skb); i++) {
+			if (!queue->skb[i])
+				continue;
+			dev_kfree_skb_any(queue->skb[i]);
+			queue->skb[i] = NULL;
+		}
+	}
+}
+
 static void mvpp2_isr_handle_link(struct mvpp2_port *port,
 				  struct phylink_pcs *pcs, bool link)
 {
@@ -4914,6 +4930,7 @@ static int mvpp2_stop(struct net_device *dev)
 		free_irq(port->port_irq, port);
 
 	mvpp2_irqs_deinit(port);
+	mvpp2_tx_hwtstamp_flush(port);
 	if (!port->has_tx_irqs) {
 		for (thread = 0; thread < port->priv->nthreads; thread++) {
 			port_pcpu = per_cpu_ptr(port->pcpu, thread);
-- 
2.34.1