From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932745AbbCXRAK (ORCPT ); Tue, 24 Mar 2015 13:00:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33147 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932301AbbCXRAG (ORCPT ); Tue, 24 Mar 2015 13:00:06 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Juergen Gross , David Vrabel Subject: [PATCH 3.14 54/79] xen/events: avoid NULL pointer dereference in dom0 on large machines Date: Tue, 24 Mar 2015 16:46:05 +0100 Message-Id: <20150324154423.665995321@linuxfoundation.org> X-Mailer: git-send-email 2.3.3 In-Reply-To: <20150324154420.803073211@linuxfoundation.org> References: <20150324154420.803073211@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Juergen Gross commit 85e40b0539b24518c8bdf63e2605c8522377d00f upstream. Using the pvops kernel a NULL pointer dereference was detected on a large machine (144 processors) when booting as dom0 in evtchn_fifo_unmask() during assignment of a pirq. The event channel in question was the first to need a new entry in event_array[] in events_fifo.c. Unfortunately xen_irq_info_pirq_setup() is called with evtchn being 0 for a new pirq and the real event channel number is assigned to the pirq only during __startup_pirq(). It is mandatory to call xen_evtchn_port_setup() after assigning the event channel number to the pirq to make sure all memory needed for the event channel is allocated. Signed-off-by: Juergen Gross Signed-off-by: David Vrabel Signed-off-by: Greg Kroah-Hartman --- drivers/xen/events/events_base.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -547,20 +547,26 @@ static unsigned int __startup_pirq(unsig pirq_query_unmask(irq); rc = set_evtchn_to_irq(evtchn, irq); - if (rc != 0) { - pr_err("irq%d: Failed to set port to irq mapping (%d)\n", - irq, rc); - xen_evtchn_close(evtchn); - return 0; - } + if (rc) + goto err; + bind_evtchn_to_cpu(evtchn, 0); info->evtchn = evtchn; + rc = xen_evtchn_port_setup(info); + if (rc) + goto err; + out: unmask_evtchn(evtchn); eoi_pirq(irq_get_irq_data(irq)); return 0; + +err: + pr_err("irq%d: Failed to set port to irq mapping (%d)\n", irq, rc); + xen_evtchn_close(evtchn); + return 0; } static unsigned int startup_pirq(struct irq_data *data)