From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756233Ab0D1S1Q (ORCPT ); Wed, 28 Apr 2010 14:27:16 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:35915 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756232Ab0D1S1O (ORCPT ); Wed, 28 Apr 2010 14:27:14 -0400 Date: Wed, 28 Apr 2010 11:26:58 -0700 From: Andrew Morton To: Prarit Bhargava Cc: linux-kernel@vger.kernel.org, suresh.b.siddha@intel.com, x86@kernel.org, clalance@redhat.com, drjones@redhat.com Subject: Re: [PATCH] Fix NULL pointer for Xen guests Message-Id: <20100428112658.4cf11292.akpm@linux-foundation.org> In-Reply-To: <20100427152434.16193.49104.sendpatchset@prarit.bos.redhat.com> References: <20100427152434.16193.49104.sendpatchset@prarit.bos.redhat.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.9; x86_64-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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Apr 2010 11:24:42 -0400 Prarit Bhargava wrote: > Upstream PV guests fail to boot because of a NULL pointer. It is possible that > xen guests have irq_desc->chip_data = NULL. > > Test for NULL chip_data pointer before attempting to complete an irq move. > > Signed-off-by: Prarit Bhargava > Acked-by: Suresh Siddha > > diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c > index 127b871..eb2789c 100644 > --- a/arch/x86/kernel/apic/io_apic.c > +++ b/arch/x86/kernel/apic/io_apic.c > @@ -2545,6 +2545,9 @@ void irq_force_complete_move(int irq) > struct irq_desc *desc = irq_to_desc(irq); > struct irq_cfg *cfg = desc->chip_data; > > + if (!cfg) > + return; > + > __irq_complete_move(&desc, cfg->vector); > } > #else I assume this is needed for 2.6.34? What about 2.6.33.x and earlier?