PM / wakeirq: Avoid setting power.wakeirq too hastily

If dev_pm_attach_wake_irq() fails, the device's power.wakeirq field
should not be set to point to the struct wake_irq passed to that
function, as that object will be freed going forward.

For this reason, make dev_pm_attach_wake_irq() first call
device_wakeup_attach_irq() and only set the device's power.wakeirq
field if that's successful.

That requires device_wakeup_attach_irq() to be called under the
device's power.lock lock, but since dev_pm_attach_wake_irq() is
the only caller of it, the requisite changes are easy to make.

Fixes: 4990d4fe327b (PM / Wakeirq: Add automated device wake IRQ handling)
Reported-by: Felipe Balbi <balbi@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 5 insertions, 7 deletions

diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
index 7470004ca810..eb6e67451dec 100644
--- a/drivers/base/power/wakeirq.c
+++ b/drivers/base/power/wakeirq.c
@@ -45,14 +45,12 @@ static int dev_pm_attach_wake_irq(struct device *dev, int irq,
 		return -EEXIST;
 	}
 
-	dev->power.wakeirq = wirq;
-	spin_unlock_irqrestore(&dev->power.lock, flags);
-
 	err = device_wakeup_attach_irq(dev, wirq);
-	if (err)
-		return err;
+	if (!err)
+		dev->power.wakeirq = wirq;
 
-	return 0;
+	spin_unlock_irqrestore(&dev->power.lock, flags);
+	return err;
 }
 
 /**
@@ -105,10 +103,10 @@ void dev_pm_clear_wake_irq(struct device *dev)
 		return;
 
 	spin_lock_irqsave(&dev->power.lock, flags);
+	device_wakeup_detach_irq(dev);
 	dev->power.wakeirq = NULL;
 	spin_unlock_irqrestore(&dev->power.lock, flags);
 
-	device_wakeup_detach_irq(dev);
 	if (wirq->dedicated_irq)
 		free_irq(wirq->irq, wirq);
 	kfree(wirq);