Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757994Ab1EaRyK (ORCPT ); Tue, 31 May 2011 13:54:10 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:49921 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757975Ab1EaRyH (ORCPT ); Tue, 31 May 2011 13:54:07 -0400 X-Authority-Analysis: v=1.1 cv=u/eXSd3k4P+OuNmbl5aZU3ellt6eTxbOnGssQLT4hSY= c=1 sm=0 a=MXrvIagEJvMA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=H8pkIGVybOjKD7cp2BsA:9 a=PUjeQqilurYA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [PATCH] ftrace: tracepoint of net_dev_xmit sees freed skb and causes panic From: Steven Rostedt To: Neil Horman Cc: Koki Sanagi , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, mingo@elte.hu, fweisbec@gmail.com, mathieu.desnoyers@efficios.com, tglx@linutronix.de, kosaki.motohiro@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, kaneshige.kenji@jp.fujitsu.com In-Reply-To: <20110531161115.GA3267@hmsreliant.think-freely.org> References: <4DE49D52.709@jp.fujitsu.com> <1306854791.11899.30.camel@gandalf.stny.rr.com> <20110531161115.GA3267@hmsreliant.think-freely.org> Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 31 May 2011 12:21:30 -0400 Message-ID: <1306858890.11899.32.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 727 Lines: 24 On Tue, 2011-05-31 at 12:11 -0400, Neil Horman wrote: > skb_dst_drop(nskb); > > > > > > + skb_len = nskb->len; > > > rc = ops->ndo_start_xmit(nskb, dev); > > > - trace_net_dev_xmit(nskb, rc); > > > + trace_net_dev_xmit(nskb, rc, dev, skb_len); > > > > What if you just put the tracepoint before the call to > > ops->ndo_start_xmit? > > > Then you won't know the return code of ndo_start_xmit, which this tracepoint > records. Doh! Yeah, I see that now ;) -- Steve -- 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/