Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161315Ab2JXWIL (ORCPT ); Wed, 24 Oct 2012 18:08:11 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:42384 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758805Ab2JXWIJ (ORCPT ); Wed, 24 Oct 2012 18:08:09 -0400 Date: Wed, 24 Oct 2012 15:08:07 -0700 From: Andrew Morton To: Ed Cashin Cc: dan.carpenter@oracle.com, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] aoe: avoid using skb member after dev_queue_xmit Message-Id: <20121024150807.82ce2677.akpm@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1223 Lines: 38 On Wed, 24 Oct 2012 14:26:13 -0400 Ed Cashin wrote: > After calling dev_queue_xmit it is no longer safe to access the > members of the skb. > > Reported-by: Dan Carpenter hm, that was clever. How did Dan detect this bug? > --- a/drivers/block/aoe/aoenet.c > +++ b/drivers/block/aoe/aoenet.c > @@ -55,12 +55,14 @@ static int > tx(void) __must_hold(&txlock) > { > struct sk_buff *skb; > + struct net_device *ifp; > > while ((skb = skb_dequeue(&skbtxq))) { > spin_unlock_irq(&txlock); > + ifp = skb->dev; > if (dev_queue_xmit(skb) == NET_XMIT_DROP && net_ratelimit()) > pr_warn("aoe: packet could not be sent on %s. %s\n", > - skb->dev ? skb->dev->name : "netif", > + ifp ? ifp->name : "netif", > "consider increasing tx_queue_len"); > spin_lock_irq(&txlock); > } Queued as a fix against the not-yet-upstream aoe-print-warning-regarding-a-common-reason-for-dropped-transmits.patch, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/