From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758357Ab0DVUWl (ORCPT ); Thu, 22 Apr 2010 16:22:41 -0400 Received: from kroah.org ([198.145.64.141]:59687 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757867Ab0DVUAV (ORCPT ); Thu, 22 Apr 2010 16:00:21 -0400 X-Mailbox-Line: From gregkh@kvm.kroah.org Thu Apr 22 12:54:10 2010 Message-Id: <20100422195410.361876407@kvm.kroah.org> User-Agent: quilt/0.48-4.4 Date: Thu, 22 Apr 2010 12:53:52 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Suresh Siddha , , , , , , Ingo Molnar Subject: [055/139] x86: Fix double enable_IR_x2apic() call on SMP kernel on !SMP boards In-Reply-To: <20100422195715.GA25490@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.33-stable review patch. If anyone has any objections, please let us know. ------------------ From: Suresh Siddha commit 472a474c6630efd195d3738339fd1bdc8aa3b1aa upstream. Jan Grossmann reported kernel boot panic while booting SMP kernel on his system with a single core cpu. SMP kernels call enable_IR_x2apic() from native_smp_prepare_cpus() and on platforms where the kernel doesn't find SMP configuration we ended up again calling enable_IR_x2apic() from the APIC_init_uniprocessor() call in the smp_sanity_check(). Thus leading to kernel panic. Don't call enable_IR_x2apic() and default_setup_apic_routing() from APIC_init_uniprocessor() in CONFIG_SMP case. NOTE: this kind of non-idempotent and assymetric initialization sequence is rather fragile and unclean, we'll clean that up in v2.6.35. This is the minimal fix for v2.6.34. Reported-by: Jan.Grossmann@kielnet.net Signed-off-by: Suresh Siddha Cc: Cc: Cc: Cc: Cc: LKML-Reference: <1270083887.7835.78.camel@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/apic/apic.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1640,8 +1640,10 @@ int __init APIC_init_uniprocessor(void) } #endif +#ifndef CONFIG_SMP enable_IR_x2apic(); default_setup_apic_routing(); +#endif verify_local_APIC(); connect_bsp_APIC();