Commit d277f9d8 authored by Juergen Gross's avatar Juergen Gross
Browse files

xen/events: increment refcnt only if event channel is refcounted 



In bind_evtchn_to_irq_chip() don't increment the refcnt of the event
channel blindly. In case the event channel is NOT refcounted, issue a
warning instead.

Add an additional safety net by doing the refcnt increment only if the
caller has specified IRQF_SHARED in the irqflags parameter.

Fixes: 9e90e58c ("xen: evtchn: Allow shared registration of IRQ handers")
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarOleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20240313071409.25913-3-jgross@suse.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 51c23bd6

drivers/xen/events/events_base.c

+13 −9
Original line number Diff line number Diff line
@@ -1190,7 +1190,7 @@ int xen_pirq_from_irq(unsigned irq) 
EXPORT_SYMBOL_GPL(xen_pirq_from_irq);



static int bind_evtchn_to_irq_chip(evtchn_port_t evtchn, struct irq_chip *chip,

				   struct xenbus_device *dev)

				   struct xenbus_device *dev, bool shared)

{

	int ret = -ENOMEM;

	struct irq_info *info;
@@ -1224,6 +1224,7 @@ static int bind_evtchn_to_irq_chip(evtchn_port_t evtchn, struct irq_chip *chip, 
		 */

		bind_evtchn_to_cpu(info, 0, false);

	} else if (!WARN_ON(info->type != IRQT_EVTCHN)) {

		if (shared && !WARN_ON(info->refcnt < 0))

			info->refcnt++;

	}
@@ -1237,13 +1238,13 @@ static int bind_evtchn_to_irq_chip(evtchn_port_t evtchn, struct irq_chip *chip, 


int bind_evtchn_to_irq(evtchn_port_t evtchn)

{

	return bind_evtchn_to_irq_chip(evtchn, &xen_dynamic_chip, NULL);

	return bind_evtchn_to_irq_chip(evtchn, &xen_dynamic_chip, NULL, false);

}

EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);



int bind_evtchn_to_irq_lateeoi(evtchn_port_t evtchn)

{

	return bind_evtchn_to_irq_chip(evtchn, &xen_lateeoi_chip, NULL);

	return bind_evtchn_to_irq_chip(evtchn, &xen_lateeoi_chip, NULL, false);

}

EXPORT_SYMBOL_GPL(bind_evtchn_to_irq_lateeoi);
@@ -1295,7 +1296,8 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu) 


static int bind_interdomain_evtchn_to_irq_chip(struct xenbus_device *dev,

					       evtchn_port_t remote_port,

					       struct irq_chip *chip)

					       struct irq_chip *chip,

					       bool shared)

{

	struct evtchn_bind_interdomain bind_interdomain;

	int err;
@@ -1307,14 +1309,14 @@ static int bind_interdomain_evtchn_to_irq_chip(struct xenbus_device *dev, 
					  &bind_interdomain);



	return err ? : bind_evtchn_to_irq_chip(bind_interdomain.local_port,

					       chip, dev);

					       chip, dev, shared);

}



int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev,

					   evtchn_port_t remote_port)

{

	return bind_interdomain_evtchn_to_irq_chip(dev, remote_port,

						   &xen_lateeoi_chip);

						   &xen_lateeoi_chip, false);

}

EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi);
@@ -1430,7 +1432,8 @@ static int bind_evtchn_to_irqhandler_chip(evtchn_port_t evtchn, 
{

	int irq, retval;



	irq = bind_evtchn_to_irq_chip(evtchn, chip, NULL);

	irq = bind_evtchn_to_irq_chip(evtchn, chip, NULL,

				      irqflags & IRQF_SHARED);

	if (irq < 0)

		return irq;

	retval = request_irq(irq, handler, irqflags, devname, dev_id);
@@ -1471,7 +1474,8 @@ static int bind_interdomain_evtchn_to_irqhandler_chip( 
{

	int irq, retval;



	irq = bind_interdomain_evtchn_to_irq_chip(dev, remote_port, chip);

	irq = bind_interdomain_evtchn_to_irq_chip(dev, remote_port, chip,

						  irqflags & IRQF_SHARED);

	if (irq < 0)

		return irq;