From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8C0DC04AB1 for ; Sun, 12 May 2019 02:39:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7C9221851 for ; Sun, 12 May 2019 02:39:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="Cqxjk/pd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726473AbfELCjF (ORCPT ); Sat, 11 May 2019 22:39:05 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:32777 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726101AbfELCjF (ORCPT ); Sat, 11 May 2019 22:39:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=aCJtuq/P6mYIusUme6l9ztDgZEanEdJposM5u/bYv6U=; b=Cqxjk/pd37PDTdPojq9hsT1ro3 5RFFX0I1Huf7MhqHvg4gG3dm2rbSoWTU1wu38w1cXYOKr+8wbe1hvV+Xnh2z4Sv6A+I+ZKLC8vgjO Vxe4Tnc/IkaIvGuFuakL0PnFT8Jrn1HxYwY/l/r6cipXdedDQMpHG1btQq1m4rIgv41A=; Received: from andrew by vps0.lunn.ch with local (Exim 4.89) (envelope-from ) id 1hPeOD-00005I-LX; Sun, 12 May 2019 04:39:01 +0200 Date: Sun, 12 May 2019 04:39:01 +0200 From: Andrew Lunn To: Vladimir Oltean Cc: f.fainelli@gmail.com, vivien.didelot@gmail.com, davem@davemloft.net, netdev@vger.kernel.org Subject: Re: [PATCH net 2/3] net: dsa: Remove dangerous DSA_SKB_CLONE() macro Message-ID: <20190512023901.GL4889@lunn.ch> References: <20190511201447.15662-1-olteanv@gmail.com> <20190511201447.15662-3-olteanv@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190511201447.15662-3-olteanv@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sat, May 11, 2019 at 11:14:46PM +0300, Vladimir Oltean wrote: > This does not cause any bug now because it has no users, but its body > contains two pointer definitions within a code block: > > struct sk_buff *clone = _clone; \ > struct sk_buff *skb = _skb; \ > > When calling the macro as DSA_SKB_CLONE(clone, skb), these variables > would obscure the arguments that the macro was called with, and the > initializers would be a no-op instead of doing their job (undefined > behavior, by the way, but GCC nicely puts NULL pointers instead). > > So simply remove this broken macro and leave users to simply call > "DSA_SKB_CB(skb)->clone = clone" by hand when needed. > > There is one functional difference when doing what I just suggested > above: the control block won't be transferred from the original skb into > the clone. Since there's no foreseen need for the control block in the > clone ATM, this is ok. > > Fixes: b68b0dd0fb2d ("net: dsa: Keep private info in the skb->cb") > Signed-off-by: Vladimir Oltean If it has no users, it should not of been merged. Reviewed-by: Andrew Lunn Andrew