From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751257AbaALJk2 (ORCPT ); Sun, 12 Jan 2014 04:40:28 -0500 Received: from mail-pb0-f46.google.com ([209.85.160.46]:35163 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751114AbaALJkZ (ORCPT ); Sun, 12 Jan 2014 04:40:25 -0500 Date: Sun, 12 Jan 2014 17:39:52 +0800 From: Bruce Liu To: peppe.cavallaro@st.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, damuzi000@gmail.com 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. Message-ID: <20140112093951.GA3743@gmail.com> References: <1389492095-6589-1-git-send-email-damuzi000@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389492095-6589-1-git-send-email-damuzi000@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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