Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934138AbcKVSJ1 (ORCPT ); Tue, 22 Nov 2016 13:09:27 -0500 Received: from mga04.intel.com ([192.55.52.120]:15346 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755445AbcKVSJZ (ORCPT ); Tue, 22 Nov 2016 13:09:25 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,533,1473145200"; d="scan'208";a="34504326" From: "Duyck, Alexander H" To: "maan@tuebingen.mpg.de" , "edumazet@google.com" CC: "linux-kernel@vger.kernel.org" , "ast@kernel.org" , "stable@vger.kernel.org" , "willemb@google.com" , "gregkh@linuxfoundation.org" , "jslaby@suse.cz" , "davem@davemloft.net" , "yibyang@cisco.com" Subject: Re: Linux 4.4.34 Thread-Topic: Linux 4.4.34 Thread-Index: AQHSROHLnoffZaunj0OqG3byajfXn6Dlwf4AgAACAwCAAAfBgIAAAWcAgAACSgCAAABsAIAAAqiAgAAAvYA= Date: Tue, 22 Nov 2016 18:08:45 +0000 Message-ID: <1479838123.681.173.camel@intel.com> References: <20161121092855.GA20976@kroah.com> <20161122165912.GA19939@tuebingen.mpg.de> <20161122170654.GA20022@kroah.com> <1479836511.681.165.camel@intel.com> <20161122175504.GD19939@tuebingen.mpg.de> <20161122180605.GE19939@tuebingen.mpg.de> In-Reply-To: <20161122180605.GE19939@tuebingen.mpg.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [134.134.2.24] Content-Type: text/plain; charset="utf-8" Content-ID: MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id uAMI9VCW031238 Content-Length: 1777 Lines: 54 On Tue, 2016-11-22 at 19:06 +0100, Andre Noll wrote: > On Tue, Nov 22, 09:56, Eric Dumazet wrote > > > > > > > > > > > > > @@ -157,6 +157,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb, > > > > memcpy(key_eth_addrs, ð->h_dest, sizeof(*key_eth_addrs)); > > > > } > > > > > > > > + barrier(); > > > > again: > > > > switch (proto) { > > > > case htons(ETH_P_IP): { > > > > > > This patch on top of v4.4.34 makes no difference: I'm still getting > > > the panic in eth_type_trans(). > > > > > > > What compiler are you using exactly ? > > gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3, as shipped with > Ubuntu-12.04. I've also tried gcc (Ubuntu 4.8.4-2ubuntu1~14.04.3) > 4.8.4 from Ubuntu-14.04. No difference. > > > > > diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c > > index 69e4463a4b1b..48791f372aa2 100644 > > --- a/net/core/flow_dissector.c > > +++ b/net/core/flow_dissector.c > > @@ -551,6 +551,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb, > > > > key_control->thoff = (u16)nhoff; > > out: > > + barrier(); > > key_basic->n_proto = proto; > > key_basic->ip_proto = ip_proto; > > No luck: Still the same panic. > > Andre Okay I think I have figured it out, but I am not sure what a good solution is. I think the problem is the fact that the keys may not be initialized until init_default_flow_dissectors is called and I am not sure that is happening before the network interface is trying to do DHCP. I have to look at the initialization framework to verify if that is the case.  It would make sense why I don't usually see it though since I usually run igb as a module and that doesn't get loaded until later if I am not mistaken. - Alex