From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756040AbZCZDlv (ORCPT ); Wed, 25 Mar 2009 23:41:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753722AbZCZDlm (ORCPT ); Wed, 25 Mar 2009 23:41:42 -0400 Received: from rhun.apana.org.au ([64.62.148.172]:55395 "EHLO arnor.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753124AbZCZDll (ORCPT ); Wed, 25 Mar 2009 23:41:41 -0400 Date: Thu, 26 Mar 2009 11:40:59 +0800 From: Herbert Xu To: David Miller Cc: jarkao2@gmail.com, mingo@elte.hu, r.schwebel@pengutronix.de, torvalds@linux-foundation.org, blaschka@linux.vnet.ibm.com, tglx@linutronix.de, a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, kernel@pengutronix.de Subject: Re: Revert "gro: Fix legacy path napi_complete crash", Message-ID: <20090326034059.GA14514@gondor.apana.org.au> References: <20090325122635.GA6489@gondor.apana.org.au> <20090325225456.GA3271@ami.dom.local> <20090326024129.GA13982@gondor.apana.org.au> <20090325.202050.08183381.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090325.202050.08183381.davem@davemloft.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 25, 2009 at 08:20:50PM -0700, David Miller wrote: > > There is still a difference compared to your fix Herbert. Jarek's > patch flushes GRO first before the unlink. > > I still believe that's critical, although like you I can't pinpoint > why. > > I know that GRO ought to be disabled here, but what if for some reason > it isn't? :-) Sure, I can accept that somehow someone has enabled GRO :) But I'd still like to know why flushing the GRO afterwards would lead to a hang. > Adam Richter has successfully tested Jarek's variant, and if Ingo's > tests show that it makes his problem go away too then I'm definitely > going with Jarek's patch. I don't have a problem with that. I've asked Adam to test my patch as well. So far the only failure case against it has been on Ingo's machine, where the process_backlog path isn't involved. Yes it's used for loopback, but he's seeing the hang on eth0, which with that config uses netif_receive_skb so it should continue to work even if process_backlog completely seizes up. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt