[PATCH 5.15 27/64] net: phy: mscc: Fix memory leak when using one step timestamping

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Horatiu Vultur <horatiu.vultur@microchip.com>

[ Upstream commit 846992645b25ec4253167e3f931e4597eb84af56 ]

Fix memory leak when running one-step timestamping. When running
one-step sync timestamping, the HW is configured to insert the TX time
into the frame, so there is no reason to keep the skb anymore. As in
this case the HW will never generate an interrupt to say that the frame
was timestamped, then the frame will never released.
Fix this by freeing the frame in case of one-step timestamping.

Fixes: 7d272e63e0979d ("net: phy: mscc: timestamping and PHC support")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://patch.msgid.link/20250522115722.2827199-1-horatiu.vultur@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 9b2bfdbf43ad ("phy: mscc: Stop taking ts_lock for tx_queue and use its own lock")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/phy/mscc/mscc_ptp.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/mscc/mscc_ptp.c b/drivers/net/phy/mscc/mscc_ptp.c
index e30e6ba9da2f4..717435562f1c5 100644
--- a/drivers/net/phy/mscc/mscc_ptp.c
+++ b/drivers/net/phy/mscc/mscc_ptp.c
@@ -1171,18 +1171,24 @@ static void vsc85xx_txtstamp(struct mii_timestamper *mii_ts,
 		container_of(mii_ts, struct vsc8531_private, mii_ts);
 
 	if (!vsc8531->ptp->configured)
-		return;
+		goto out;
 
-	if (vsc8531->ptp->tx_type == HWTSTAMP_TX_OFF) {
-		kfree_skb(skb);
-		return;
-	}
+	if (vsc8531->ptp->tx_type == HWTSTAMP_TX_OFF)
+		goto out;
+
+	if (vsc8531->ptp->tx_type == HWTSTAMP_TX_ONESTEP_SYNC)
+		if (ptp_msg_is_sync(skb, type))
+			goto out;
 
 	skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
 
 	mutex_lock(&vsc8531->ts_lock);
 	__skb_queue_tail(&vsc8531->ptp->tx_queue, skb);
 	mutex_unlock(&vsc8531->ts_lock);
+	return;
+
+out:
+	kfree_skb(skb);
 }
 
 static bool vsc85xx_rxtstamp(struct mii_timestamper *mii_ts,
-- 
2.50.1