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Commit c2b341a6 authored by Jonas Jensen's avatar Jonas Jensen Committed by David S. Miller
Browse files

net: moxa: fix TX overrun memory leak 

moxart_mac_start_xmit() doesn't care where tx_tail is, tx_head can
catch and pass tx_tail, which is bad because moxart_tx_finished()
isn't guaranteed to catch up on freeing resources from tx_tail.

Add a check in moxart_mac_start_xmit() stopping the queue at the
end of the circular buffer. Also add a check in moxart_tx_finished()
waking the queue if the buffer has TX_WAKE_THRESHOLD or more
free descriptors.

While we're at it, move spin_lock_irq() to happen before our
descriptor pointer is assigned in moxart_mac_start_xmit().

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=99451



Signed-off-by: default avatarJonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent af109a2c

drivers/net/ethernet/moxa/moxart_ether.c

+18 −2
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/of_irq.h>

#include <linux/crc32.h>

#include <linux/crc32c.h>

#include <linux/circ_buf.h>



#include "moxart_ether.h"
@@ -278,6 +279,13 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget) 
	return rx;

}



static int moxart_tx_queue_space(struct net_device *ndev)

{

	struct moxart_mac_priv_t *priv = netdev_priv(ndev);



	return CIRC_SPACE(priv->tx_head, priv->tx_tail, TX_DESC_NUM);

}



static void moxart_tx_finished(struct net_device *ndev)

{

	struct moxart_mac_priv_t *priv = netdev_priv(ndev);
@@ -297,6 +305,9 @@ static void moxart_tx_finished(struct net_device *ndev) 
		tx_tail = TX_NEXT(tx_tail);

	}

	priv->tx_tail = tx_tail;

	if (netif_queue_stopped(ndev) &&

	    moxart_tx_queue_space(ndev) >= TX_WAKE_THRESHOLD)

		netif_wake_queue(ndev);

}



static irqreturn_t moxart_mac_interrupt(int irq, void *dev_id)
@@ -324,13 +335,18 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev) 
	struct moxart_mac_priv_t *priv = netdev_priv(ndev);

	void *desc;

	unsigned int len;

	unsigned int tx_head = priv->tx_head;

	unsigned int tx_head;

	u32 txdes1;

	int ret = NETDEV_TX_BUSY;



	spin_lock_irq(&priv->txlock);



	tx_head = priv->tx_head;

	desc = priv->tx_desc_base + (TX_REG_DESC_SIZE * tx_head);



	spin_lock_irq(&priv->txlock);

	if (moxart_tx_queue_space(ndev) == 1)

		netif_stop_queue(ndev);



	if (moxart_desc_read(desc + TX_REG_OFFSET_DESC0) & TX_DESC0_DMA_OWN) {

		net_dbg_ratelimited("no TX space for packet\n");

		priv->stats.tx_dropped++;

drivers/net/ethernet/moxa/moxart_ether.h

+1 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ 
#define TX_NEXT(N)		(((N) + 1) & (TX_DESC_NUM_MASK))

#define TX_BUF_SIZE		1600

#define TX_BUF_SIZE_MAX		(TX_DESC1_BUF_SIZE_MASK+1)

#define TX_WAKE_THRESHOLD	16



#define RX_DESC_NUM		64

#define RX_DESC_NUM_MASK	(RX_DESC_NUM-1)