2013-08-24 19:21:13

by Boris BREZILLON

Subject: [PATCH] net/cadence/macb: fix kernel Oops if no PHY were discovered during probe

Test the presence of a PHY device before printing attached PHY
informations.

Signed-off-by: Boris BREZILLON <[email protected]>
---
drivers/net/ethernet/cadence/macb.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index e866608..fd3b67f 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -1868,8 +1868,10 @@ static int __init macb_probe(struct platform_device *pdev)
dev->irq, dev->dev_addr);

phydev = bp->phy_dev;
- netdev_info(dev, "attached PHY driver [%s] (mii_bus:phy_addr=%s, irq=%d)\n",
- phydev->drv->name, dev_name(&phydev->dev), phydev->irq);
+ if (phydev)
+ netdev_info(dev, "attached PHY driver [%s] (mii_bus:phy_addr=%s, irq=%d)\n",
+ phydev->drv->name, dev_name(&phydev->dev),
+ phydev->irq);

return 0;

--
1.7.9.5

2013-08-26 07:43:34

by Nicolas Ferre

Subject: Re: [PATCH] net/cadence/macb: fix kernel Oops if no PHY were discovered during probe

On 24/08/2013 21:21, Boris BREZILLON :
> Test the presence of a PHY device before printing attached PHY
> informations.
>
> Signed-off-by: Boris BREZILLON <[email protected]>

Acked-by: Nicolas Ferre <[email protected]>

> ---
> drivers/net/ethernet/cadence/macb.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index e866608..fd3b67f 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -1868,8 +1868,10 @@ static int __init macb_probe(struct platform_device *pdev)
> dev->irq, dev->dev_addr);
>
> phydev = bp->phy_dev;
> - netdev_info(dev, "attached PHY driver [%s] (mii_bus:phy_addr=%s, irq=%d)\n",
> - phydev->drv->name, dev_name(&phydev->dev), phydev->irq);
> + if (phydev)
> + netdev_info(dev, "attached PHY driver [%s] (mii_bus:phy_addr=%s, irq=%d)\n",
> + phydev->drv->name, dev_name(&phydev->dev),
> + phydev->irq);
>
> return 0;
>
>


--
Nicolas Ferre

2013-08-26 09:10:18

by Bo Shen

Subject: Re: [PATCH] net/cadence/macb: fix kernel Oops if no PHY were discovered during probe

Hi Boris,

On 08/25/2013 03:21 AM, Boris BREZILLON wrote:
> Test the presence of a PHY device before printing attached PHY
> informations.
>
> Signed-off-by: Boris BREZILLON <[email protected]>
> ---
> drivers/net/ethernet/cadence/macb.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index e866608..fd3b67f 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -1868,8 +1868,10 @@ static int __init macb_probe(struct platform_device *pdev)
> dev->irq, dev->dev_addr);
>
> phydev = bp->phy_dev;
> - netdev_info(dev, "attached PHY driver [%s] (mii_bus:phy_addr=%s, irq=%d)\n",
> - phydev->drv->name, dev_name(&phydev->dev), phydev->irq);
> + if (phydev)
> + netdev_info(dev, "attached PHY driver [%s] (mii_bus:phy_addr=%s, irq=%d)\n",
> + phydev->drv->name, dev_name(&phydev->dev),
> + phydev->irq);

Actually no need this check, if PHY is attached failed, the macb driver
probe will fail, then it won't show this message.

> return 0;
>
>

Best Regards,
Bo Shen

2013-08-26 12:01:44

by Boris BREZILLON

Subject: Re: [PATCH] net/cadence/macb: fix kernel Oops if no PHY were discovered during probe

Hello Bo,

On 26/08/2013 11:09, Bo Shen wrote:
> Hi Boris,
>
> On 08/25/2013 03:21 AM, Boris BREZILLON wrote:
>> Test the presence of a PHY device before printing attached PHY
>> informations.
>>
>> Signed-off-by: Boris BREZILLON <[email protected]>
>> ---
>> drivers/net/ethernet/cadence/macb.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/cadence/macb.c
>> b/drivers/net/ethernet/cadence/macb.c
>> index e866608..fd3b67f 100644
>> --- a/drivers/net/ethernet/cadence/macb.c
>> +++ b/drivers/net/ethernet/cadence/macb.c
>> @@ -1868,8 +1868,10 @@ static int __init macb_probe(struct
>> platform_device *pdev)
>> dev->irq, dev->dev_addr);
>>
>> phydev = bp->phy_dev;
>> - netdev_info(dev, "attached PHY driver [%s] (mii_bus:phy_addr=%s,
>> irq=%d)\n",
>> - phydev->drv->name, dev_name(&phydev->dev), phydev->irq);
>> + if (phydev)
>> + netdev_info(dev, "attached PHY driver [%s]
>> (mii_bus:phy_addr=%s, irq=%d)\n",
>> + phydev->drv->name, dev_name(&phydev->dev),
>> + phydev->irq);
>
> Actually no need this check, if PHY is attached failed, the macb
> driver probe will fail, then it won't show this message.

You're right (thanks for pointing this out).
Indeed this is a bug I introduced in this patch series (
https://lkml.org/lkml/2013/8/22/381).

In macb_mii_init function, the err field may be set to 0 (instead of the
default -ENXIO value) if no PHY
is discovered.
As macb_mii_probe return code is not copied to err, this result in a 0
return even if macb_mii_probe
failed.

Nicolas, forget about this patch, I'll fix this in the appropriate patch
series (except if you plan to add
dynamic MAC/PHY association, and treat missing PHY during probe process
as an acceptable result :-)).

Best Regards,

Boris BREZILLON

>
>> return 0;
>>
>>
>
> Best Regards,
> Bo Shen