Subject: Re: [PATCH 6/6] net: phy: Stop 'phy-state-machine' and 'phy_change' work on remove

From: Florian Fainelli <[email-masked]>
Date: Tue, 27 Oct 2015 08:40:30 -0700

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 <[email-masked]>
> Signed-off-by: Neil Armstrong <[email-masked]>
> ---
>  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