From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932472AbWGSEFb (ORCPT ); Wed, 19 Jul 2006 00:05:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932489AbWGSEFb (ORCPT ); Wed, 19 Jul 2006 00:05:31 -0400 Received: from smtp.osdl.org ([65.172.181.4]:10477 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S932472AbWGSEFb (ORCPT ); Wed, 19 Jul 2006 00:05:31 -0400 Date: Tue, 18 Jul 2006 21:04:58 -0700 From: Andrew Morton To: "Gary Funck" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu Subject: Re: 2.6.17-1.2145_FC5 mmap-related soft lockup Message-Id: <20060718210458.45f9460e.akpm@osdl.org> In-Reply-To: <200607190225.k6J2PGAq004975@intrepid.intrepid.com> References: <20060715221942.9f1543ca.akpm@osdl.org> <200607190225.k6J2PGAq004975@intrepid.intrepid.com> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.19; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 18 Jul 2006 19:25:16 -0700 "Gary Funck" wrote: > > > > > Are you able to confirm that setting CONFIG_DEBUG_SPINLOCK=n fixes it? > > > > And are you able to get us a copy of that test app? > > Yes, I just ran the test with 2.6.17.6. With CONFIG_DEBUG_SPINLOCK=y > the test fails and the soft lockup situation often results. > However, when built with CONFIG_DEBUG_SPINLOCK=n, the test passes, > and runs rather quickly in comparison to when it fails. > > I've attached a slightly updated version of the test case. > It is a little more carefully crafted and prints some > output so that you have some idea that it is working. > That's great, thanks. That pretty much confirms that this long-standing box-killing rwlock starvation bug is specific to Opterons. Neither Ingo nor I have Opteron machines so a fix will take a little longer than one would expect. Meanwhile, an appropriate workaround is to disable CONFIG_DEBUG_SPINLOCK.