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Commit b4c9784c authored by Niklas Cassel's avatar Niklas Cassel Committed by David S. Miller
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net: stmmac: WARN if tx_skbuff entries are reused before cleared 



The current code assumes that a tx_skbuff entry has been cleared
by stmmac_tx_clean() before stmmac_xmit()/stmmac_tso_xmit()
assigns a new skb to that entry. However, since we never check
the current value before overwriting it, it is theoretically
possible that a non-NULL value is overwritten.

Add WARN_ONs to verify that each entry in tx_skbuff is NULL
before it is assigned a new value.

Signed-off-by: default avatarNiklas Cassel <niklas.cassel@axis.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f66b533d

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+5 −0
Original line number Diff line number Diff line
@@ -2794,6 +2794,7 @@ static void stmmac_tso_allocator(struct stmmac_priv *priv, unsigned int des, 


	while (tmp_len > 0) {

		tx_q->cur_tx = STMMAC_GET_ENTRY(tx_q->cur_tx, DMA_TX_SIZE);

		WARN_ON(tx_q->tx_skbuff[tx_q->cur_tx]);

		desc = tx_q->dma_tx + tx_q->cur_tx;



		desc->des0 = cpu_to_le32(des + (total_len - tmp_len));
@@ -2878,6 +2879,7 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) 
		priv->hw->desc->set_mss(mss_desc, mss);

		tx_q->mss = mss;

		tx_q->cur_tx = STMMAC_GET_ENTRY(tx_q->cur_tx, DMA_TX_SIZE);

		WARN_ON(tx_q->tx_skbuff[tx_q->cur_tx]);

	}



	if (netif_msg_tx_queued(priv)) {
@@ -2888,6 +2890,7 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) 
	}



	first_entry = tx_q->cur_tx;

	WARN_ON(tx_q->tx_skbuff[first_entry]);



	desc = tx_q->dma_tx + first_entry;

	first = desc;
@@ -3062,6 +3065,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) 


	entry = tx_q->cur_tx;

	first_entry = entry;

	WARN_ON(tx_q->tx_skbuff[first_entry]);



	csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL);
@@ -3090,6 +3094,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) 
		bool last_segment = (i == (nfrags - 1));



		entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);

		WARN_ON(tx_q->tx_skbuff[entry]);



		if (likely(priv->extend_desc))

			desc = (struct dma_desc *)(tx_q->dma_etx + entry);