Re: [PATCH] net: phy: dp83869: fix memory corruption when enabling fiber

[Ingo van Lil]

On 10/1/24 12:40, Sverdlin, Alexander wrote:

> > diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c
> > index d7aaefb5226b..9c5ac5d6a9fd 100644
> > --- a/drivers/net/phy/dp83869.c
> > +++ b/drivers/net/phy/dp83869.c
> > @@ -645,7 +645,7 @@ static int dp83869_configure_fiber(struct phy_device *phydev,
> >   		     phydev->supported);
> >
> >   	linkmode_set_bit(ETHTOOL_LINK_MODE_FIBRE_BIT, phydev->supported);
> > -	linkmode_set_bit(ADVERTISED_FIBRE, phydev->advertising);
> > +	linkmode_set_bit(ETHTOOL_LINK_MODE_FIBRE_BIT, phydev->advertising);
>
> Are you sure this linkmode_set_bit() is required at all?

You're right, it's probably not required. I just tracked a weird bug
down to this clear mistake and wanted to change as little as possible.

The logic of the function seems a bit odd to me: At the beginning,
advertising is ANDed with supported, and at the end it's ORed again.
Inside the function they are mostly manipulated together.

Couldn't that be replaced with a simple "phydev->advertising =
phydev->supported;" at the end?

Regards,
Ingo