From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753118AbYGINvA (ORCPT ); Wed, 9 Jul 2008 09:51:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754304AbYGINul (ORCPT ); Wed, 9 Jul 2008 09:50:41 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:42913 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754141AbYGINuk (ORCPT ); Wed, 9 Jul 2008 09:50:40 -0400 Date: Wed, 9 Jul 2008 15:49:44 +0200 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Nick Piggin , LKML , Jens Axboe , Peter Zijlstra , Christoph Lameter , Petr Tesarik , Virtualization , Xen devel , Thomas Friebel , Avi Kivity , the arch/x86 maintainers Subject: [patch] x86, paravirt-spinlocks: fix boot hang (was: Re: [PATCH RFC 0/4] Paravirtual spinlocks) Message-ID: <20080709134944.GA15190@elte.hu> References: <20080707190749.299430659@goop.org> <20080709122852.GA30579@elte.hu> <20080709133358.GA7005@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080709133358.GA7005@elte.hu> 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=3.2.3 -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 * Ingo Molnar wrote: > the patches caused a boot hang with this config: > > http://redhat.com/~mingo/misc/config-Wed_Jul__9_14_47_04_CEST_2008.bad ok, fixed it via the patch below. Ingo --------------> commit 6412367fe22dc54cc727e7bec5bd65c36c1a0754 Author: Ingo Molnar Date: Wed Jul 9 15:42:09 2008 +0200 x86, paravirt-spinlocks: fix boot hang the paravirt-spinlock patches caused a boot hang with this config: http://redhat.com/~mingo/misc/config-Wed_Jul__9_14_47_04_CEST_2008.bad i have bisected it down to: | commit e17b58c2e85bc2ad2afc07fb8d898017c2b75ed1 | Author: Jeremy Fitzhardinge | Date: Mon Jul 7 12:07:53 2008 -0700 | | xen: implement Xen-specific spinlocks i.e. applying that patch alone causes the hang. The hang happens in the ftrace self-test: initcall utsname_sysctl_init+0x0/0x19 returned 0 after 0 msecs calling init_sched_switch_trace+0x0/0x4c Testing tracer sched_switch: PASSED initcall init_sched_switch_trace+0x0/0x4c returned 0 after 167 msecs calling init_function_trace+0x0/0x12 Testing tracer ftrace: [hard hang] it should have continued like this: Testing tracer ftrace: PASSED initcall init_function_trace+0x0/0x12 returned 0 after 198 msecs calling init_irqsoff_tracer+0x0/0x14 Testing tracer irqsoff: PASSED initcall init_irqsoff_tracer+0x0/0x14 returned 0 after 3 msecs calling init_mmio_trace+0x0/0x12 initcall init_mmio_trace+0x0/0x12 returned 0 after 0 msecs the problem is that such lowlevel primitives as spinlocks should never be built with -pg (which ftrace does). Marking paravirt.o as non-pg and marking all spinlock ops as always-inline solve the hang. Signed-off-by: Ingo Molnar diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 2dd1ccd..faba669 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -7,10 +7,11 @@ extra-y := head_$(BITS).o head$(BITS).o head.o init_task.o vmlinu CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE) ifdef CONFIG_FTRACE -# Do not profile debug utilities +# Do not profile debug and lowlevel utilities CFLAGS_REMOVE_tsc_64.o = -pg CFLAGS_REMOVE_tsc_32.o = -pg CFLAGS_REMOVE_rtc.o = -pg +CFLAGS_REMOVE_paravirt.o = -pg endif #