On Tue, Sep 10, 2024 at 06:19:54AM +0000, Jacky Chou wrote:
> Hello, Dan
>
> > On Mon, Sep 09, 2024 at 02:03:32PM +0200, Andrew Lunn wrote:
> > > > > Are you actually saying:
> > > > >
> > > > > if (netdev->phydev) {
> > > > > /* If we have a PHY, start polling */
> > > > > phy_start(netdev->phydev);
> > > > > }
> > > > >
> > > > > is wrong, it is guaranteed there is always a phydev?
> > > > >
> > > > This patch is focus on error handling when using NC-SI at open stage.
> > > >
> > > > if (netdev->phydev) {
> > > > /* If we have a PHY, start polling */
> > > > phy_start(netdev->phydev);
> > > > }
> > > >
> > > > This code is used to check the other cases.
> > > > Perhaps, phy-handle or fixed-link property are not added in DTS.
> > >
> > > I'm guessing, but i think the static analysers see this condition, and
> > > deducing that phydev might be a NULL. Hence when phy_stop() is called,
> > > it needs the check.
> > >
> > > You say the static analyser is wrong, probably because it cannot check
> > > the bigger context. It can be NULL for phy_start() but not for
> > > phy_stop(). Maybe you can give it some more hints?
> > >
> > > Dan, is this Smatch? Is it possible to dump the paths through the code
> > > where it thinks it might be NULL?
> >
> > Adding a check here is the correct thing. The current code works because we
> > only have the one goto after the call to phy_start(netdev->phydev), but as soon
> > as we add a second goto then it will crash.
>
> Could you share more detail about the crash is happening when you add a second goto?
> I'm wondering if there are other things I missed.
I'm saying if we add a feature in the future. Something like this.
regards,
dan carpenter
diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index f3cc14cc757d..417c7f4dd471 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -1562,10 +1562,22 @@ static int ftgmac100_open(struct net_device *netdev)
goto err_ncsi;
}
+ ret = some_new_feature();
+ if (ret)
+ goto err_free_ncsi;
+
return 0;
+err_free_ncsi:
+ if (priv->use_ncsi)
+ ncsi_stop_dev(priv->ndev);
err_ncsi:
phy_stop(netdev->phydev);
^^^^^^^^^^^^^^
Crash.
napi_disable(&priv->napi);
netif_stop_queue(netdev);
err_alloc:
