From: Juergen Gross <jgross@xxxxxxxx>
[ Upstream commit 85e40b0539b24518c8bdf63e2605c8522377d00f ]
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@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 3.14+
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
drivers/xen/events/events_base.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index b4bca2d..70fba97 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)
--
2.1.0
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