Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757959AbZKEOyN (ORCPT ); Thu, 5 Nov 2009 09:54:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757786AbZKEOyM (ORCPT ); Thu, 5 Nov 2009 09:54:12 -0500 Received: from mail-ew0-f207.google.com ([209.85.219.207]:36984 "EHLO mail-ew0-f207.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757761AbZKEOyL (ORCPT ); Thu, 5 Nov 2009 09:54:11 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=UJ6BMmidRT9ABmXhGLTCvqA7YzdSESjOA0kQfAGy2635Vk8M9rOQhjEYEJJZC8DTc/ etXkGE3GJgZ14zxInkEY5cXGFECrmb2Anz60oRapq/8Rw3gKVEYN5s8pyK40cJVomabK eSebVqn6B/lNrLsweCQrNDFIoc86zjs1WVjXU= MIME-Version: 1.0 In-Reply-To: <20091105141055.GA17350@redhat.com> References: <6417.1257351084@turing-police.cc.vt.edu> <200911051941.03401.rusty@rustcorp.com.au> <20091105141055.GA17350@redhat.com> Date: Thu, 5 Nov 2009 15:54:15 +0100 Message-ID: <6e0cfd1d0911050654q2e1f23e6o2b47edfdcf3137cb@mail.gmail.com> Subject: Re: 2.6.32-rc5-mmotm1101 - lockdep whinge during early boot From: Martin Schwidefsky To: Oleg Nesterov Cc: Rusty Russell , Valdis.Kletnieks@vt.edu, Andrew Morton , Thomas Gleixner , linux-kernel@vger.kernel.org, Ingo Molnar , Heiko Carstens Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1383 Lines: 36 That is imho caused by this patch snippet from the linux-next.patch from mmotd: diff -puN arch/x86/kernel/tsc.c~linux-next arch/x86/kernel/tsc.c --- a/arch/x86/kernel/tsc.c~linux-next +++ a/arch/x86/kernel/tsc.c @@ -763,14 +763,12 @@ void mark_tsc_unstable(char *reason) { if (!tsc_unstable) { tsc_unstable = 1; - printk(KERN_INFO "Marking TSC unstable due to %s\n", reason); + printk("Marking TSC unstable due to %s\n", reason); /* Change only the rating, when not registered */ if (clocksource_tsc.mult) - clocksource_mark_unstable(&clocksource_tsc); - else { - clocksource_tsc.flags |= CLOCK_SOURCE_UNSTABLE; + clocksource_change_rating(&clocksource_tsc, 0); + else clocksource_tsc.rating = 0; - } } } The upstream variant of mark_tsc_unstable uses clocksource_mark_unstable which does not take the mutex. The reason is the clocksource mutex vs. the cpu_add_remove_lock spinlock. -- blue skies, Martin -- 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/