Subject: Re: [PATCH 1/1] When timestamping is enabled, stmmac_tx_clean will call stmmac_get_tx_hwtstamp to get tx TS. It's possible that skb is NULL because there are other network frames that use several descriptors. So we must return immediately in stmmac_get_tx_hwtstamp if skb is NULL to avoid system crash.

From: Bruce Liu <[email-masked]>
Date: Sun, 12 Jan 2014 17:39:52 +0800

When timestamping is enabled, stmmac_tx_clean will call stmmac_get_tx_hwtstamp to get tx TS.
 It's possible that skb is NULL because there are other network frames that use several descriptors.
 So we must return immediately in stmmac_get_tx_hwtstamp if skb is NULL to avoid system crash.

Signed-off-by: Bruce Liu <[email-masked]>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 797b56a..47f2287 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -332,7 +332,7 @@ static void stmmac_get_tx_hwtstamp(struct stmmac_priv *priv,
 		return;
 
 	/* exit if skb doesn't support hw tstamp */
-	if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)))
+	if (likely(!skb || !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)))
 		return;
 
 	if (priv->adv_ts)
-- 
1.7.9.5