* [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove
@ 2015-10-27 14:49 Neil Armstrong
2015-10-27 15:40 ` Florian Fainelli
0 siblings, 1 reply; 5+ messages in thread
From: Neil Armstrong @ 2015-10-27 14:49 UTC (permalink / raw)
To: David S. Miller
Cc: Andrew Lunn, Florian Fainelli, Guenter Roeck, vivien.didelot,
Fabian Frederick, Pavel Nakonechny, Joe Perches, netdev,
linux-kernel, Frode Isaksen
Avoids:
Unable to handle kernel NULL pointer dereference at virtual address 00000064
Workqueue: events_power_efficient phy_state_machine
PC is at phy_state_machine+0x28/0x480
Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
drivers/net/phy/phy_device.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 3833891..b5b6c1b 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1348,6 +1348,12 @@ static int phy_remove(struct device *dev)
phydev->state = PHY_DOWN;
mutex_unlock(&phydev->lock);
+ cancel_delayed_work_sync(&phydev->state_queue);
+ flush_delayed_work(&phydev->state_queue);
+
+ cancel_work_sync(&phydev->phy_queue);
+ flush_work(&phydev->phy_queue);
+
if (phydev->drv->remove)
phydev->drv->remove(phydev);
phydev->drv = NULL;
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove
2015-10-27 14:49 [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove Neil Armstrong
@ 2015-10-27 15:40 ` Florian Fainelli
[not found] ` <CAJ03sU_+nkvN1ZeqvWx56B7cb9GDCbpTFn6gJp2OmW-CKi7QFA@mail.gmail.com>
0 siblings, 1 reply; 5+ messages in thread
From: Florian Fainelli @ 2015-10-27 15:40 UTC (permalink / raw)
To: Neil Armstrong, David S. Miller
Cc: Andrew Lunn, Guenter Roeck, vivien.didelot, Fabian Frederick,
Pavel Nakonechny, Joe Perches, netdev, linux-kernel,
Frode Isaksen
On 27/10/15 07:49, Neil Armstrong wrote:
> Avoids:
> Unable to handle kernel NULL pointer dereference at virtual address 00000064
> Workqueue: events_power_efficient phy_state_machine
> PC is at phy_state_machine+0x28/0x480
Stripped down oops can sometimes be missing critical pieces of
information to help debug the problem, is there a reason why this is
being obfuscated?
You are supposed to stop the PHY state machine by calling
phy_disconnect() is it possible that this is missing?
>
> Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
> drivers/net/phy/phy_device.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 3833891..b5b6c1b 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -1348,6 +1348,12 @@ static int phy_remove(struct device *dev)
> phydev->state = PHY_DOWN;
> mutex_unlock(&phydev->lock);
>
> + cancel_delayed_work_sync(&phydev->state_queue);
> + flush_delayed_work(&phydev->state_queue);
> +
> + cancel_work_sync(&phydev->phy_queue);
> + flush_work(&phydev->phy_queue);
> +
> if (phydev->drv->remove)
> phydev->drv->remove(phydev);
> phydev->drv = NULL;
>
--
Florian
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove
[not found] ` <CAJ03sU_+nkvN1ZeqvWx56B7cb9GDCbpTFn6gJp2OmW-CKi7QFA@mail.gmail.com>
@ 2015-10-27 15:57 ` Florian Fainelli
2015-10-27 21:20 ` Andrew Lunn
0 siblings, 1 reply; 5+ messages in thread
From: Florian Fainelli @ 2015-10-27 15:57 UTC (permalink / raw)
To: Frode Isaksen
Cc: Neil Armstrong, David S. Miller, Andrew Lunn, Guenter Roeck,
vivien.didelot, Fabian Frederick, Pavel Nakonechny, Joe Perches,
netdev, linux-kernel
(don't top post please)
On 27/10/15 08:53, Frode Isaksen wrote:
> What will you need in the oops ? I presume you don' want everything or ?
>
> The PHY state machine is not stopped with a PHY disconnect.
It is stopped with a phy_disconnect():
/**
* phy_disconnect - disable interrupts, stop state machine, and detach a PHY
* device
* @phydev: target phy_device struct
*/
void phy_disconnect(struct phy_device *phydev)
{
if (phydev->irq > 0)
phy_stop_interrupts(phydev);
phy_stop_machine(phydev);
phydev->adjust_link = NULL;
phy_detach(phydev);
}
> However, the
> 'phy-change' work is cancelled, so cancelling this work in the remove
> function maybe not needed. I will verify ASAP.
>
> Frode
>
> 2015-10-27 16:40 GMT+01:00 Florian Fainelli <f.fainelli@gmail.com
> <mailto:f.fainelli@gmail.com>>:
>
> On 27/10/15 07:49, Neil Armstrong wrote:
> > Avoids:
> > Unable to handle kernel NULL pointer dereference at virtual address 00000064
> > Workqueue: events_power_efficient phy_state_machine
> > PC is at phy_state_machine+0x28/0x480
>
> Stripped down oops can sometimes be missing critical pieces of
> information to help debug the problem, is there a reason why this is
> being obfuscated?
>
> You are supposed to stop the PHY state machine by calling
> phy_disconnect() is it possible that this is missing?
>
> >
> > Signed-off-by: Frode Isaksen <fisaksen@baylibre.com
> <mailto:fisaksen@baylibre.com>>
> > Signed-off-by: Neil Armstrong <narmstrong@baylibre.com
> <mailto:narmstrong@baylibre.com>>
> > ---
> > drivers/net/phy/phy_device.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/net/phy/phy_device.c
> b/drivers/net/phy/phy_device.c
> > index 3833891..b5b6c1b 100644
> > --- a/drivers/net/phy/phy_device.c
> > +++ b/drivers/net/phy/phy_device.c
> > @@ -1348,6 +1348,12 @@ static int phy_remove(struct device *dev)
> > phydev->state = PHY_DOWN;
> > mutex_unlock(&phydev->lock);
> >
> > + cancel_delayed_work_sync(&phydev->state_queue);
> > + flush_delayed_work(&phydev->state_queue);
> > +
> > + cancel_work_sync(&phydev->phy_queue);
> > + flush_work(&phydev->phy_queue);
> > +
> > if (phydev->drv->remove)
> > phydev->drv->remove(phydev);
> > phydev->drv = NULL;
> >
>
>
> --
> Florian
>
>
--
Florian
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove
2015-10-27 15:57 ` Florian Fainelli
@ 2015-10-27 21:20 ` Andrew Lunn
[not found] ` <CAJ03sU9Uw9SLXGpH9wqm+GWJtFZvcSuW=YCTZseSanpNeF_+Sw@mail.gmail.com>
0 siblings, 1 reply; 5+ messages in thread
From: Andrew Lunn @ 2015-10-27 21:20 UTC (permalink / raw)
To: Florian Fainelli
Cc: Frode Isaksen, Neil Armstrong, David S. Miller, Guenter Roeck,
vivien.didelot, Fabian Frederick, Pavel Nakonechny, Joe Perches,
netdev, linux-kernel
On Tue, Oct 27, 2015 at 08:57:58AM -0700, Florian Fainelli wrote:
> (don't top post please)
>
> On 27/10/15 08:53, Frode Isaksen wrote:
> > What will you need in the oops ? I presume you don' want everything or ?
> >
> > The PHY state machine is not stopped with a PHY disconnect.
>
> It is stopped with a phy_disconnect():
>
> /**
> * phy_disconnect - disable interrupts, stop state machine, and detach a PHY
> * device
> * @phydev: target phy_device struct
> */
> void phy_disconnect(struct phy_device *phydev)
> {
> if (phydev->irq > 0)
> phy_stop_interrupts(phydev);
>
> phy_stop_machine(phydev);
>
> phydev->adjust_link = NULL;
>
> phy_detach(phydev);
> }
And this does not yet get called. It probably needs to be in
dsa_switch_destroy() just before unregister_netdev() of the slave
devices.
However, the ordering in dsa_switch_destroy() looks wrong. The fixed
phys are destroyed before the slave devices. They should probably be
destroyed after the slave devices, or at least after the
phy_disconnect() is called.
Andrew
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove
[not found] ` <CAJ03sU9Uw9SLXGpH9wqm+GWJtFZvcSuW=YCTZseSanpNeF_+Sw@mail.gmail.com>
@ 2015-10-28 13:54 ` Neil Armstrong
0 siblings, 0 replies; 5+ messages in thread
From: Neil Armstrong @ 2015-10-28 13:54 UTC (permalink / raw)
To: Frode Isaksen, Andrew Lunn
Cc: Florian Fainelli, David S. Miller, Guenter Roeck, vivien.didelot,
Fabian Frederick, Pavel Nakonechny, Joe Perches, netdev,
linux-kernel
> > void phy_disconnect(struct phy_device *phydev)
> > {
> > if (phydev->irq > 0)
> > phy_stop_interrupts(phydev);
> >
> > phy_stop_machine(phydev);
> >
> > phydev->adjust_link = NULL;
> >
> > phy_detach(phydev);
> > }
>
> And this does not yet get called. It probably needs to be in
> dsa_switch_destroy() just before unregister_netdev() of the slave
> devices.
>
> However, the ordering in dsa_switch_destroy() looks wrong. The fixed
> phys are destroyed before the slave devices. They should probably be
> destroyed after the slave devices, or at least after the
> phy_disconnect() is called.
>
> Andrew
>
Andrew, Florian,
Thanks for the review, a call to phy_disconnect was missing in dsa_switch_destroy.
I will post a new patchset with the correct fix, a switch to delayed_work and
a separate dsa_slave_destroy function for sake of maintenance ease.
Neil
^ permalink raw reply [flat|nested] 5+ messages in thread
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2015-10-27 14:49 [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove Neil Armstrong
2015-10-27 15:40 ` Florian Fainelli
[not found] ` <CAJ03sU_+nkvN1ZeqvWx56B7cb9GDCbpTFn6gJp2OmW-CKi7QFA@mail.gmail.com>
2015-10-27 15:57 ` Florian Fainelli
2015-10-27 21:20 ` Andrew Lunn
[not found] ` <CAJ03sU9Uw9SLXGpH9wqm+GWJtFZvcSuW=YCTZseSanpNeF_+Sw@mail.gmail.com>
2015-10-28 13:54 ` Neil Armstrong
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