Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757811AbZCXOkW (ORCPT ); Tue, 24 Mar 2009 10:40:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754358AbZCXOkH (ORCPT ); Tue, 24 Mar 2009 10:40:07 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:44703 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754203AbZCXOkF (ORCPT ); Tue, 24 Mar 2009 10:40:05 -0400 Date: Tue, 24 Mar 2009 15:39:42 +0100 From: Ingo Molnar To: Robert Schwebel Cc: Linus Torvalds , Herbert Xu , Frank Blaschka , "David S. Miller" , Thomas Gleixner , Peter Zijlstra , Linux Kernel Mailing List , kernel@pengutronix.de Subject: Re: Revert "gro: Fix legacy path napi_complete crash", (was: Re: Linux 2.6.29) Message-ID: <20090324143942.GA20462@elte.hu> References: <20090324130202.GA32469@elte.hu> <20090324143303.GP5367@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090324143303.GP5367@pengutronix.de> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2916 Lines: 92 * Robert Schwebel wrote: > On Tue, Mar 24, 2009 at 02:02:02PM +0100, Ingo Molnar wrote: > > If the box hung within 15 minutes, the kernel was deemed bad. Using > > that method i arrived to this upstream networking fix which was > > merged yesterday: > > > > | 303c6a0251852ecbdc5c15e466dcaff5971f7517 is first bad commit > > | commit 303c6a0251852ecbdc5c15e466dcaff5971f7517 > > | Author: Herbert Xu > > | Date: Tue Mar 17 13:11:29 2009 -0700 > > | > > | gro: Fix legacy path napi_complete crash > > This commit breaks nfsroot booting on i.MX27 and other ARM boxes > with different network cards here in a reproducable way. Can you confirm that Herbert's fix (see it below) solves the problem? Ingo ---------------> >From b8b66ac07cab1b45aac93e4f406833a1e0d7677e Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 24 Mar 2009 21:35:42 +0800 Subject: [PATCH] net: Fix netpoll lockup in legacy receive path When I fixed the GRO crash in the legacy receive path I used napi_complete to replace __napi_complete. Unfortunately they're not the same when NETPOLL is enabled, which may result in us not calling __napi_complete at all. While this is fishy in itself, let's make the obvious fix right now of reverting to the previous state where we always called __napi_complete. Signed-off-by: Herbert Xu Cc: Linus Torvalds Cc: Frank Blaschka Cc: "David S. Miller" Cc: Peter Zijlstra LKML-Reference: <20090324133542.GA29046@gondor.apana.org.au> Signed-off-by: Ingo Molnar --- net/core/dev.c | 16 +++++++++------- 1 files changed, 9 insertions(+), 7 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index e3fe5c7..523f53e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2580,24 +2580,26 @@ static int process_backlog(struct napi_struct *napi, int quota) int work = 0; struct softnet_data *queue = &__get_cpu_var(softnet_data); unsigned long start_time = jiffies; + struct sk_buff *skb; napi->weight = weight_p; do { - struct sk_buff *skb; - local_irq_disable(); skb = __skb_dequeue(&queue->input_pkt_queue); - if (!skb) { - local_irq_enable(); - napi_complete(napi); - goto out; - } local_irq_enable(); + if (!skb) + break; napi_gro_receive(napi, skb); } while (++work < quota && jiffies == start_time); napi_gro_flush(napi); + if (skb) + goto out; + + local_irq_disable(); + __napi_complete(napi); + local_irq_enable(); out: return work; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/