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

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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: 9e90e58c11 ("xen: evtchn: Allow shared registration of IRQ handers")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Link: https://lore.kernel.org/r/20240313071409.25913-3-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Juergen Gross 2024-03-13 08:14:09 +01:00
parent 51c23bd691
commit d277f9d828
1 changed files with 13 additions and 9 deletions
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22
drivers/xen/events/events_base.c
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@ -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;
@ -1224,7 +1224,8 @@ 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)) {
info->refcnt++;
if (shared && !WARN_ON(info->refcnt < 0))
info->refcnt++;
}
ret = info->irq;
@ -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;