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authorJuergen Gross <jgross@suse.com>2015-02-26 06:52:05 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2015-03-06 14:16:32 +0100
commit85e40b0539b24518c8bdf63e2605c8522377d00f (patch)
treec495ad825da2b79d0a22987631826c1c370d4dc4 /drivers/xen/events
parentxen: Remove trailing semicolon from xenbus_register_frontend() definition (diff)
downloadlinux-85e40b0539b24518c8bdf63e2605c8522377d00f.tar.xz
linux-85e40b0539b24518c8bdf63e2605c8522377d00f.zip
xen/events: avoid NULL pointer dereference in dom0 on large machines
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 <jgross@suse.com> Cc: <stable@vger.kernel.org> # 3.14+ Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'drivers/xen/events')
-rw-r--r--drivers/xen/events/events_base.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index b4bca2d4a7e5..70fba973a107 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -526,20 +526,26 @@ static unsigned int __startup_pirq(unsigned int irq)
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)