From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net v2] ipvlan: fix crash when master is set in loopback mode Date: Mon, 19 Dec 2016 11:11:56 -0500 (EST) Message-ID: <20161219.111156.1987012114474401231.davem@davemloft.net> References: <1482087625-30366-1-git-send-email-mahesh@bandewar.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, edumazet@google.com, maheshb@google.com To: mahesh@bandewar.net Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:46880 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755441AbcLSQL6 (ORCPT ); Mon, 19 Dec 2016 11:11:58 -0500 In-Reply-To: <1482087625-30366-1-git-send-email-mahesh@bandewar.net> Sender: netdev-owner@vger.kernel.org List-ID: From: Mahesh Bandewar Date: Sun, 18 Dec 2016 11:00:25 -0800 > From: Mahesh Bandewar > > In an IPvlan setup when master is set in loopback mode e.g. > > ethtool -K eth0 set loopback on > > where eth0 is master device for IPvlan setup. > > The failure actually happens while processing mulitcast packets > but that's a result of unconditionally queueing packets without > ensuring ether-header is part of the linear part of skb. > > This patch forces this check at the reception and drops packets > which fail this check before queuing them. ... > Signed-off-by: Mahesh Bandewar > --- > v1->v2: commit log update Like Eric, I still do not like this change nor the explanation. Whether in loopback mode or not, your explanation makes no sense at all. If the packet comes from the ethernet device, the freakin' ethernet header is there in the linear SKB area. No pulling should be needed whatsoever. Something creates this bad situation where the ethernet header is not there, but you have not explained that sufficiently yet. Thank you.