From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752611AbZHHRIV (ORCPT ); Sat, 8 Aug 2009 13:08:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752554AbZHHRIV (ORCPT ); Sat, 8 Aug 2009 13:08:21 -0400 Received: from mail.atlantis.sk ([80.94.52.35]:57680 "EHLO mail.atlantis.sk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752553AbZHHRIU (ORCPT ); Sat, 8 Aug 2009 13:08:20 -0400 From: Ondrej Zary To: tglx@linutronix.de Subject: [PATCH] OOPS in identify_cpu() on CPUs without CPUID Date: Sat, 8 Aug 2009 19:08:10 +0200 User-Agent: KMail/1.9.10 Cc: mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200908081908.12240.linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kernel is broken for x86 CPUs without CPUID since 2.6.28. It crashes with NULL pointer dereference in identify_cpu(): 766 generic_identify(c); 767 768--> if (this_cpu->c_identify) 769 this_cpu->c_identify(c); this_cpu is NULL. This is because it's only initialized in get_cpu_vendor() function, which is not called if the CPU has no CPUID instruction. Signed-off-by: Ondrej Zary --- linux-2.6.30.4-orig/arch/x86/kernel/cpu/common.c 2009-06-10 05:05:27.000000000 +0200 +++ linux-2.6.30.4-router/arch/x86/kernel/cpu/common.c 2009-08-08 18:00:21.000000000 +0200 @@ -699,6 +699,7 @@ static void __cpuinit generic_identify(struct cpuinfo_x86 *c) { + this_cpu = &default_cpu; c->extended_cpuid_level = 0; if (!have_cpuid_p()) -- Ondrej Zary