Re: net: phy: realtek: regression, kernel null pointer dereference

[Vicente Bergas]

On Friday, May 10, 2019 10:28:06 PM CEST, Heiner Kallweit wrote:
> On 10.05.2019 17:05, Vicente Bergas wrote:
> > Hello,
> > there is a regression on linux v5.1-9573-gb970afcfcabd with a kernel null
> > pointer dereference.
> > The issue is the commit f81dadbcf7fd067baf184b63c179fc392bdb226e
> >  net: phy: realtek: Add rtl8211e rx/tx delays config ...
> The page operation callbacks are missing in the RTL8211E driver.
> I just submitted a fix adding these callbacks to few Realtek PHY drivers
> including RTl8211E. This should fix the issue.

Hello Heiner,
just tried your patch and indeed the NPE is gone. But still no network...
The MAC <-> PHY link was working before, so, maybe the rgmii delays are not
correctly configured.
With this change it is back to working:
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -300,7 +300,6 @@
	}, {
		PHY_ID_MATCH_EXACT(0x001cc915),
		.name		= "RTL8211E Gigabit Ethernet",
-		.config_init	= &rtl8211e_config_init,
		.ack_interrupt	= &rtl821x_ack_interrupt,
		.config_intr	= &rtl8211e_config_intr,
		.suspend	= genphy_suspend,
That is basically reverting the patch.

Regards,
 VicenÃ.

> Nevertheless your proposed patch looks good to me, just one small change
> would be needed and it should be splitted.
>
> The change to phy-core I would consider a fix and it should be fine to
> submit it to net (net-next is closed currently).
>
> Adding the warning to the Realtek driver is fine, but this would be
> something for net-next once it's open again.
>
> > Regards,
> >  VicenÃ.
> Heiner
>
> > --- a/drivers/net/phy/phy-core.c
> > +++ b/drivers/net/phy/phy-core.c
> > @@ -648,11 +648,17 @@
> >
> > static int __phy_read_page(struct phy_device *phydev)
> > { ...
>
> Here phydev_warn() should be used.
>
> > +        return 0;
> > +    }
> >
> >     ret = phy_write(phydev, RTL821x_EXT_PAGE_SELECT, 0xa4);
> >     if (ret)