From b4c9784cbff43a2b50f6db6e2400c8d003c21546 Mon Sep 17 00:00:00 2001 From: Niklas Cassel Date: Mon, 19 Feb 2018 18:11:11 +0100 Subject: [PATCH] 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: Niklas Cassel Signed-off-by: David S. Miller --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 24afe77..9881df1 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -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); -- 2.7.4