2017-09-26 19:01:07

by Vivien Didelot

Subject: [PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

mv88e6xxx_g2_irq_free locks the registers mutex, but not
mv88e6xxx_g1_irq_free, which results in a stack trace from
assert_reg_lock when unloading the mv88e6xxx module. Fix this.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Vivien Didelot <[email protected]>
---
drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index c6678aa9b4ef..e7ff7483d2fb 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
if (chip->irq > 0) {
if (chip->info->g2_irqs > 0)
mv88e6xxx_g2_irq_free(chip);
+ mutex_lock(&chip->reg_lock);
mv88e6xxx_g1_irq_free(chip);
+ mutex_unlock(&chip->reg_lock);
}
}

--
2.14.1

2017-09-26 19:05:44

by Florian Fainelli

Subject: Re: [PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

On 09/26/2017 11:57 AM, Vivien Didelot wrote:
> mv88e6xxx_g2_irq_free locks the registers mutex, but not
> mv88e6xxx_g1_irq_free, which results in a stack trace from
> assert_reg_lock when unloading the mv88e6xxx module. Fix this.
>
> Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
> Signed-off-by: Vivien Didelot <[email protected]>

Reviewed-by: Florian Fainelli <[email protected]>
--
Florian

2017-09-27 09:06:15

by David Laight

Subject: RE: [PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

From: Vivien Didelot
> Sent: 26 September 2017 19:57
> mv88e6xxx_g2_irq_free locks the registers mutex, but not
> mv88e6xxx_g1_irq_free, which results in a stack trace from
> assert_reg_lock when unloading the mv88e6xxx module. Fix this.
>
> Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
> Signed-off-by: Vivien Didelot <[email protected]>
> ---
> drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index c6678aa9b4ef..e7ff7483d2fb 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
> if (chip->irq > 0) {
> if (chip->info->g2_irqs > 0)
> mv88e6xxx_g2_irq_free(chip);
> + mutex_lock(&chip->reg_lock);
> mv88e6xxx_g1_irq_free(chip);
> + mutex_unlock(&chip->reg_lock);

Isn't the irq_free code likely to have to sleep waiting for any
ISR to complete??

David

2017-09-27 13:07:17

by Andrew Lunn

Subject: Re: [PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

On Wed, Sep 27, 2017 at 09:06:01AM +0000, David Laight wrote:
> From: Vivien Didelot
> > Sent: 26 September 2017 19:57
> > mv88e6xxx_g2_irq_free locks the registers mutex, but not
> > mv88e6xxx_g1_irq_free, which results in a stack trace from
> > assert_reg_lock when unloading the mv88e6xxx module. Fix this.
> >
> > Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
> > Signed-off-by: Vivien Didelot <[email protected]>
> > ---
> > drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> > index c6678aa9b4ef..e7ff7483d2fb 100644
> > --- a/drivers/net/dsa/mv88e6xxx/chip.c
> > +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> > @@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
> > if (chip->irq > 0) {
> > if (chip->info->g2_irqs > 0)
> > mv88e6xxx_g2_irq_free(chip);
> > + mutex_lock(&chip->reg_lock);
> > mv88e6xxx_g1_irq_free(chip);
> > + mutex_unlock(&chip->reg_lock);
>
> Isn't the irq_free code likely to have to sleep waiting for any
> ISR to complete??

Hi David

Possibly. But this is a mutex, not a spinlock. So sleeping is O.K.
Or am i missing something?

Andrew

2017-09-27 16:40:41

by David Laight

Subject: RE: [PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

From: Andrew Lunn
> Sent: 27 September 2017 14:07
> To: David Laight
> On Wed, Sep 27, 2017 at 09:06:01AM +0000, David Laight wrote:
> > From: Vivien Didelot
> > > Sent: 26 September 2017 19:57
> > > mv88e6xxx_g2_irq_free locks the registers mutex, but not
> > > mv88e6xxx_g1_irq_free, which results in a stack trace from
> > > assert_reg_lock when unloading the mv88e6xxx module. Fix this.
> > >
> > > Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
> > > Signed-off-by: Vivien Didelot <[email protected]>
> > > ---
> > > drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> > > index c6678aa9b4ef..e7ff7483d2fb 100644
> > > --- a/drivers/net/dsa/mv88e6xxx/chip.c
> > > +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> > > @@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
> > > if (chip->irq > 0) {
> > > if (chip->info->g2_irqs > 0)
> > > mv88e6xxx_g2_irq_free(chip);
> > > + mutex_lock(&chip->reg_lock);
> > > mv88e6xxx_g1_irq_free(chip);
> > > + mutex_unlock(&chip->reg_lock);
> >
> > Isn't the irq_free code likely to have to sleep waiting for any
> > ISR to complete??
>
> Hi David
>
> Possibly. But this is a mutex, not a spinlock. So sleeping is O.K.
> Or am i missing something?

Looks like I was missing some coffee :-)

David

2017-09-28 17:29:10

by David Miller

Subject: Re: [PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

From: Vivien Didelot <[email protected]>
Date: Tue, 26 Sep 2017 14:57:21 -0400

> mv88e6xxx_g2_irq_free locks the registers mutex, but not
> mv88e6xxx_g1_irq_free, which results in a stack trace from
> assert_reg_lock when unloading the mv88e6xxx module. Fix this.
>
> Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
> Signed-off-by: Vivien Didelot <[email protected]>

Applied and queued up for -stable.