base: power: wakeirq: don't leak dev->power.wakeirq
diff mbox

Message ID 2783932.o7RC7vMDHB@vostro.rjw.lan
State New
Headers show

Commit Message

Rafael J. Wysocki July 6, 2015, 11:13 p.m. UTC
On Monday, July 06, 2015 01:01:18 PM Felipe Balbi wrote:
> on a first call to dev_pm_attach_wake_irq(), if it
> fails, it will leave dev->power.wakeirq set to a
> dangling pointer. Instead, let's clear it to make
> sure a subsequent call to dev_pm_attach_wake_irq()
> has chance to succeed.
> 
> Cc: Tony Lindgren <tmlind@atomide.com>
> Signed-off-by: Felipe Balbi <balbi@ti.com>
> ---
>  drivers/base/power/wakeirq.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
> index 7470004ca810..394d250a1ad8 100644
> --- a/drivers/base/power/wakeirq.c
> +++ b/drivers/base/power/wakeirq.c
> @@ -50,9 +50,16 @@ static int dev_pm_attach_wake_irq(struct device *dev, int irq,
>  
>  	err = device_wakeup_attach_irq(dev, wirq);
>  	if (err)
> -		return err;
> +		goto err_cleanup;
>  
>  	return 0;
> +
> +err_cleanup:
> +	spin_lock_irqsave(&dev->power.lock, flags);
> +	dev->power.wakeirq = NULL;
> +	spin_unlock_irqrestore(&dev->power.lock, flags);
> +
> +	return err;
>  }

Too many labels for me and the fact that acquiring of the lock again in the error
patch doesn't look good.

However, we can do the entire device_wakeup_attach_irq() under the lock (after
removing the locking from it), because we're its only caller.

So what about the below instead (build-tested only)?

Rafael


---
 drivers/base/power/wakeirq.c |   12 +++++-------
 drivers/base/power/wakeup.c  |   31 ++++++++++---------------------
 2 files changed, 15 insertions(+), 28 deletions(-)


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Comments

Tony Lindgren July 7, 2015, 7:40 a.m. UTC | #1
* Rafael J. Wysocki <rjw@rjwysocki.net> [150706 15:49]:
> On Monday, July 06, 2015 01:01:18 PM Felipe Balbi wrote:
> > on a first call to dev_pm_attach_wake_irq(), if it
> > fails, it will leave dev->power.wakeirq set to a
> > dangling pointer. Instead, let's clear it to make
> > sure a subsequent call to dev_pm_attach_wake_irq()
> > has chance to succeed.
> > 
> > Cc: Tony Lindgren <tmlind@atomide.com>
> > Signed-off-by: Felipe Balbi <balbi@ti.com>
> > ---
> >  drivers/base/power/wakeirq.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
> > index 7470004ca810..394d250a1ad8 100644
> > --- a/drivers/base/power/wakeirq.c
> > +++ b/drivers/base/power/wakeirq.c
> > @@ -50,9 +50,16 @@ static int dev_pm_attach_wake_irq(struct device *dev, int irq,
> >  
> >  	err = device_wakeup_attach_irq(dev, wirq);
> >  	if (err)
> > -		return err;
> > +		goto err_cleanup;
> >  
> >  	return 0;
> > +
> > +err_cleanup:
> > +	spin_lock_irqsave(&dev->power.lock, flags);
> > +	dev->power.wakeirq = NULL;
> > +	spin_unlock_irqrestore(&dev->power.lock, flags);
> > +
> > +	return err;
> >  }
> 
> Too many labels for me and the fact that acquiring of the lock again in the error
> patch doesn't look good.
> 
> However, we can do the entire device_wakeup_attach_irq() under the lock (after
> removing the locking from it), because we're its only caller.
> 
> So what about the below instead (build-tested only)?

Nice, still works for me and simplifies things:

Tested-by: Tony Lindgren <tony@atomide.com>
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Felipe Balbi July 7, 2015, 8:11 a.m. UTC | #2
On Tue, Jul 07, 2015 at 12:40:53AM -0700, Tony Lindgren wrote:
> * Rafael J. Wysocki <rjw@rjwysocki.net> [150706 15:49]:
> > On Monday, July 06, 2015 01:01:18 PM Felipe Balbi wrote:
> > > on a first call to dev_pm_attach_wake_irq(), if it
> > > fails, it will leave dev->power.wakeirq set to a
> > > dangling pointer. Instead, let's clear it to make
> > > sure a subsequent call to dev_pm_attach_wake_irq()
> > > has chance to succeed.
> > > 
> > > Cc: Tony Lindgren <tmlind@atomide.com>
> > > Signed-off-by: Felipe Balbi <balbi@ti.com>
> > > ---
> > >  drivers/base/power/wakeirq.c | 9 ++++++++-
> > >  1 file changed, 8 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
> > > index 7470004ca810..394d250a1ad8 100644
> > > --- a/drivers/base/power/wakeirq.c
> > > +++ b/drivers/base/power/wakeirq.c
> > > @@ -50,9 +50,16 @@ static int dev_pm_attach_wake_irq(struct device *dev, int irq,
> > >  
> > >  	err = device_wakeup_attach_irq(dev, wirq);
> > >  	if (err)
> > > -		return err;
> > > +		goto err_cleanup;
> > >  
> > >  	return 0;
> > > +
> > > +err_cleanup:
> > > +	spin_lock_irqsave(&dev->power.lock, flags);
> > > +	dev->power.wakeirq = NULL;
> > > +	spin_unlock_irqrestore(&dev->power.lock, flags);
> > > +
> > > +	return err;
> > >  }
> > 
> > Too many labels for me and the fact that acquiring of the lock again in the error
> > patch doesn't look good.
> > 
> > However, we can do the entire device_wakeup_attach_irq() under the lock (after
> > removing the locking from it), because we're its only caller.
> > 
> > So what about the below instead (build-tested only)?
> 
> Nice, still works for me and simplifies things:
> 
> Tested-by: Tony Lindgren <tony@atomide.com>

Cool, thanks for testing Tony. Rafael, I'm fine with your version too.
FWIW:

Reported-by: Felipe Balbi <balbi@ti.com>
Rafael J. Wysocki July 7, 2015, 11:11 a.m. UTC | #3
On Tue, Jul 7, 2015 at 10:11 AM, Felipe Balbi <balbi@ti.com> wrote:
> On Tue, Jul 07, 2015 at 12:40:53AM -0700, Tony Lindgren wrote:
>> * Rafael J. Wysocki <rjw@rjwysocki.net> [150706 15:49]:
>> > On Monday, July 06, 2015 01:01:18 PM Felipe Balbi wrote:
>> > > on a first call to dev_pm_attach_wake_irq(), if it
>> > > fails, it will leave dev->power.wakeirq set to a
>> > > dangling pointer. Instead, let's clear it to make
>> > > sure a subsequent call to dev_pm_attach_wake_irq()
>> > > has chance to succeed.
>> > >
>> > > Cc: Tony Lindgren <tmlind@atomide.com>
>> > > Signed-off-by: Felipe Balbi <balbi@ti.com>
>> > > ---
>> > >  drivers/base/power/wakeirq.c | 9 ++++++++-
>> > >  1 file changed, 8 insertions(+), 1 deletion(-)
>> > >
>> > > diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
>> > > index 7470004ca810..394d250a1ad8 100644
>> > > --- a/drivers/base/power/wakeirq.c
>> > > +++ b/drivers/base/power/wakeirq.c
>> > > @@ -50,9 +50,16 @@ static int dev_pm_attach_wake_irq(struct device *dev, int irq,
>> > >
>> > >   err = device_wakeup_attach_irq(dev, wirq);
>> > >   if (err)
>> > > -         return err;
>> > > +         goto err_cleanup;
>> > >
>> > >   return 0;
>> > > +
>> > > +err_cleanup:
>> > > + spin_lock_irqsave(&dev->power.lock, flags);
>> > > + dev->power.wakeirq = NULL;
>> > > + spin_unlock_irqrestore(&dev->power.lock, flags);
>> > > +
>> > > + return err;
>> > >  }
>> >
>> > Too many labels for me and the fact that acquiring of the lock again in the error
>> > patch doesn't look good.
>> >
>> > However, we can do the entire device_wakeup_attach_irq() under the lock (after
>> > removing the locking from it), because we're its only caller.
>> >
>> > So what about the below instead (build-tested only)?
>>
>> Nice, still works for me and simplifies things:
>>
>> Tested-by: Tony Lindgren <tony@atomide.com>
>
> Cool, thanks for testing Tony. Rafael, I'm fine with your version too.
> FWIW:
>
> Reported-by: Felipe Balbi <balbi@ti.com>

OK, applied.

Thanks,
Rafael
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Patch
diff mbox

Index: linux-pm/drivers/base/power/wakeirq.c
===================================================================
--- linux-pm.orig/drivers/base/power/wakeirq.c
+++ linux-pm/drivers/base/power/wakeirq.c
@@ -45,14 +45,12 @@  static int dev_pm_attach_wake_irq(struct
 		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
 		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);
Index: linux-pm/drivers/base/power/wakeup.c
===================================================================
--- linux-pm.orig/drivers/base/power/wakeup.c
+++ linux-pm/drivers/base/power/wakeup.c
@@ -281,32 +281,25 @@  EXPORT_SYMBOL_GPL(device_wakeup_enable);
  * Attach a device wakeirq to the wakeup source so the device
  * wake IRQ can be configured automatically for suspend and
  * resume.
+ *
+ * Call under the device's power.lock lock.
  */
 int device_wakeup_attach_irq(struct device *dev,
 			     struct wake_irq *wakeirq)
 {
 	struct wakeup_source *ws;
-	int ret = 0;
 
-	spin_lock_irq(&dev->power.lock);
 	ws = dev->power.wakeup;
 	if (!ws) {
 		dev_err(dev, "forgot to call call device_init_wakeup?\n");
-		ret = -EINVAL;
-		goto unlock;
+		return -EINVAL;
 	}
 
-	if (ws->wakeirq) {
-		ret = -EEXIST;
-		goto unlock;
-	}
+	if (ws->wakeirq)
+		return -EEXIST;
 
 	ws->wakeirq = wakeirq;
-
-unlock:
-	spin_unlock_irq(&dev->power.lock);
-
-	return ret;
+	return 0;
 }
 
 /**
@@ -314,20 +307,16 @@  unlock:
  * @dev: Device to handle
  *
  * Removes a device wakeirq from the wakeup source.
+ *
+ * Call under the device's power.lock lock.
  */
 void device_wakeup_detach_irq(struct device *dev)
 {
 	struct wakeup_source *ws;
 
-	spin_lock_irq(&dev->power.lock);
 	ws = dev->power.wakeup;
-	if (!ws)
-		goto unlock;
-
-	ws->wakeirq = NULL;
-
-unlock:
-	spin_unlock_irq(&dev->power.lock);
+	if (ws)
+		ws->wakeirq = NULL;
 }
 
 /**