From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264765AbUD1MqV (ORCPT ); Wed, 28 Apr 2004 08:46:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264771AbUD1MqV (ORCPT ); Wed, 28 Apr 2004 08:46:21 -0400 Received: from mx2.redhat.com ([66.187.237.31]:45197 "EHLO mx2.redhat.com") by vger.kernel.org with ESMTP id S264765AbUD1MqS (ORCPT ); Wed, 28 Apr 2004 08:46:18 -0400 From: Jeff Moyer MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16527.42815.447695.474344@segfault.boston.redhat.com> Date: Wed, 28 Apr 2004 08:44:47 -0400 To: Matt Mackall Cc: linux-kernel@vger.kernel.org Subject: Re: netconsole hangs w/ alt-sysrq-t In-Reply-To: <20040425191543.GV28459@waste.org> References: <16519.58589.773562.492935@segfault.boston.redhat.com> <20040425191543.GV28459@waste.org> X-Mailer: VM 7.14 under 21.4 (patch 13) "Rational FORTRAN" XEmacs Lucid Reply-To: jmoyer@redhat.com X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org ==> Regarding Re: netconsole hangs w/ alt-sysrq-t; Matt Mackall adds: mpm> On Thu, Apr 22, 2004 at 11:29:33AM -0400, Jeff Moyer wrote: >> If netconsole is enabled, and you hit Alt-Sysrq-t, then it will print a >> small amount of output to the console(s) and then hang the system. In >> this case, I'm using the e100 driver, and we end up exhausting the >> available cbs. Since we are in interrupt context, the driver's poll >> routine is never run, and we loop infinitely waiting for resources to >> free up that never will. Kernel version is 2.6.5. mpm> Can you try 2.6.6-rc2? It has a fix to congestion handling that should mpm> address this. Is the attached patch the change you are referring to? If so, I don't see how this would fix the problem. I ended up deferring netpoll writes to process context, which has been working fine for me. Have I missed something? -Jeff # This is a BitKeeper generated diff -Nru style patch. # # ChangeSet # 2004/04/13 14:07:53-04:00 mpm@selenic.com # [PATCH] netpoll transmit busy bugfix # # Fix for handling of full transmit queue when netpoll trap is enabled. # # From Stelian Pop # # net/core/netpoll.c # 2004/04/10 16:19:31-04:00 mpm@selenic.com +3 -9 # netpoll transmit busy bugfix # diff -Nru a/net/core/netpoll.c b/net/core/netpoll.c --- a/net/core/netpoll.c Wed Apr 28 05:43:08 2004 +++ b/net/core/netpoll.c Wed Apr 28 05:43:08 2004 @@ -163,21 +163,15 @@ spin_lock(&np->dev->xmit_lock); np->dev->xmit_lock_owner = smp_processor_id(); - if (netif_queue_stopped(np->dev)) { - np->dev->xmit_lock_owner = -1; - spin_unlock(&np->dev->xmit_lock); - - netpoll_poll(np); - goto repeat; - } - status = np->dev->hard_start_xmit(skb, np->dev); np->dev->xmit_lock_owner = -1; spin_unlock(&np->dev->xmit_lock); /* transmit busy */ - if(status) + if(status) { + netpoll_poll(np); goto repeat; + } } void netpoll_send_udp(struct netpoll *np, const char *msg, int len)