Re: [PATCH] net: smsc911x: Fix unload crash when link is up

[Jeremy Linton]

Hi,

On 03/06/2018 09:23 AM, Andrew Lunn wrote:
> > This is caused by the mdiobus being unregistered/free'd
> > and the code in phy_detach() attempting to manipulate mdio
> > related structures from unregister_netdev() calling close()
> >
> > To fix this, we delay the mdiobus teardown until after
> > the netdev is deregistered.
> >
> > Reported-by: Matt Sealey <matt.sealey@xxxxxxx>
> > Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
> > ---
> >   drivers/net/ethernet/smsc/smsc911x.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c
> > index 012fb66eed8d..f0afb88d7bc2 100644
> > --- a/drivers/net/ethernet/smsc/smsc911x.c
> > +++ b/drivers/net/ethernet/smsc/smsc911x.c
> > @@ -2335,14 +2335,14 @@ static int smsc911x_drv_remove(struct platform_device *pdev)
> >   	pdata = netdev_priv(dev);
> >   	BUG_ON(!pdata);
> >   	BUG_ON(!pdata->ioaddr);
> > -	WARN_ON(dev->phydev);
>
> Hi Jeremy
>
> I assume this WARN_ON() also fired? It would be good to comment about
> why you removed it, that the code now handles that case.

Yes, the phydev is started and assigned in the netdev _open and 
stopped/set to null in the _stop. Since the module remove is not blocked 
by having the netdev active, and unregister_netdev closes out active 
connections, the WARN_ON would needlessly trigger if the netdev was 
still open.

> Apart from that
>
> Reviewed-by: Andrew Lunn <andrew@xxxxxxx>

Thanks for looking at this.