Commit 9dda66ac authored by Vladimir Oltean's avatar Vladimir Oltean Committed by David S. Miller
Browse files

net: mscc: ocelot: fix race condition with TX timestamping 



The TX-timestampable skb is added late to the ocelot_port->tx_skbs. It
is in a race with the TX timestamp IRQ, which checks that queue trying
to match the timestamp with the skb by the ts_id. The skb should be
added to the queue before the IRQ can fire.

Fixes: 4e3b0468 ("net: mscc: PTP Hardware Clock (PHC) support")
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarHoratiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5f6857e8

drivers/net/ethernet/mscc/ocelot_net.c

+8 −6
Original line number Diff line number Diff line
@@ -330,6 +330,7 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev) 
	u8 grp = 0; /* Send everything on CPU group 0 */

	unsigned int i, count, last;

	int port = priv->chip_port;

	bool do_tstamp;



	val = ocelot_read(ocelot, QS_INJ_STATUS);

	if (!(val & QS_INJ_STATUS_FIFO_RDY(BIT(grp))) ||
@@ -344,10 +345,14 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev) 
	info.vid = skb_vlan_tag_get(skb);



	/* Check if timestamping is needed */

	do_tstamp = (ocelot_port_add_txtstamp_skb(ocelot_port, skb) == 0);



	if (ocelot->ptp && shinfo->tx_flags & SKBTX_HW_TSTAMP) {

		info.rew_op = ocelot_port->ptp_cmd;

		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)

		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {

			info.rew_op |= (ocelot_port->ts_id  % 4) << 3;

			ocelot_port->ts_id++;

		}

	}



	ocelot_gen_ifh(ifh, &info);
@@ -380,12 +385,9 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev) 
	dev->stats.tx_packets++;

	dev->stats.tx_bytes += skb->len;



	if (!ocelot_port_add_txtstamp_skb(ocelot_port, skb)) {

		ocelot_port->ts_id++;

		return NETDEV_TX_OK;

	}



	if (!do_tstamp)

		dev_kfree_skb_any(skb);



	return NETDEV_TX_OK;

}