From owner-freebsd-current@FreeBSD.ORG Thu Feb 24 14:57:37 2005 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A1B4016A4CE for ; Thu, 24 Feb 2005 14:57:37 +0000 (GMT) Received: from smtp813.mail.sc5.yahoo.com (smtp813.mail.sc5.yahoo.com [66.163.170.83]) by mx1.FreeBSD.org (Postfix) with SMTP id 3D29543D55 for ; Thu, 24 Feb 2005 14:57:37 +0000 (GMT) (envelope-from noackjr@alumni.rice.edu) Received: from unknown (HELO optimator.noacks.org) (noacks@swbell.net@70.240.176.125 with login) by smtp813.mail.sc5.yahoo.com with SMTP; 24 Feb 2005 14:57:37 -0000 Received: from localhost (localhost [127.0.0.1]) by optimator.noacks.org (Postfix) with ESMTP id 160A56189; Thu, 24 Feb 2005 08:57:36 -0600 (CST) Received: from optimator.noacks.org ([127.0.0.1]) by localhost (optimator.noacks.org [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 04540-10-3; Thu, 24 Feb 2005 08:57:34 -0600 (CST) Received: from [127.0.0.1] (optimator [192.168.1.11]) by optimator.noacks.org (Postfix) with ESMTP id 4F6A26159; Thu, 24 Feb 2005 08:57:34 -0600 (CST) Message-ID: <421DEB5D.9090703@alumni.rice.edu> Date: Thu, 24 Feb 2005 08:57:33 -0600 From: Jon Noack User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Robert Watson References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: amavisd-new at noacks.org cc: current@freebsd.org Subject: Re: panic: Duplicate free of item 0xc2580a00 from zone 0xc103e9a0(Mbuf) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: noackjr@alumni.rice.edu List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Feb 2005 14:57:37 -0000 Robert Watson wrote: > On Thu, 24 Feb 2005, Peter Holm wrote: >>With GENERIC HEAD from Feb 23 06:23 UTC + mpsafe_vfs = 1 I got: >> >>Slab at 0xc2580fa8, freei 10 = 0. panic: Duplicate free of item >>0xc2580a00 from zone 0xc103e9a0(Mbuf) > > rl_encap() appears to be pretty broken in the event that m_defrag() has to > allocate a new mbuf on the head of the chain. Specifcally, rl_encap() > may allocate a new head to the chain, but the caller won't use that new > head, instead using the old head (which may have been free'd, or otherwise > munged). This might also explain other crashes or panics involving rl > interfaces. I'm surprised this lasted as long as it apparently has in the > wild (since 2003?). From src/sys/pci/if_rl.c: "The RealTek 8139 PCI NIC redefines the meaning of 'low end.' This is probably the worst PCI ethernet controller ever made, with the possible exception of the FEAST chip made by SMC. The 8139 supports bus-master DMA, but it has a terrible interface that nullifies any performance gains that bus-master DMA usually offers. ..." I would bet that (in)famous comment coupled with everyone recommending fxp or em adapters[1] causes most who experience problems to abandon rl adapters at the first hint of trouble. In that type of an environment, it is not overly surprising to me that a bug could last this long. Jon [1] I use fxp and em adapters and I've never had a problem with them. As such, I can't argue with the recommendation.