Subject: Re: [PATCH net-next 2/4] net: mvpp2: add mvpp2_phylink_to_port() helper

From: Russell King - ARM Linux admin <[email-masked]>
Date: Mon, 2 Nov 2020 23:02:09 +0000

On Mon, Nov 02, 2020 at 06:38:54PM +0100, Marcin Wojtas wrote:
> Hi Greg and Sasha,
> 
> pt., 9 paź 2020 o 05:43 Marcin Wojtas <[email-masked]> napisał(a):
> >
> > Hi,
> >
> > sob., 20 cze 2020 o 11:21 Russell King <[email-masked]> napisał(a):
> > >
> > > Add a helper to convert the struct phylink_config pointer passed in
> > > from phylink to the drivers internal struct mvpp2_port.
> > >
> > > Signed-off-by: Russell King <[email-masked]>
> > > ---
> > >  .../net/ethernet/marvell/mvpp2/mvpp2_main.c   | 29 +++++++++----------
> > >  1 file changed, 14 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > index 7653277d03b7..313f5a60a605 100644
> > > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > @@ -4767,12 +4767,16 @@ static void mvpp2_port_copy_mac_addr(struct net_device *dev, struct mvpp2 *priv,
> > >         eth_hw_addr_random(dev);
> > >  }
> > >
> > > +static struct mvpp2_port *mvpp2_phylink_to_port(struct phylink_config *config)
> > > +{
> > > +       return container_of(config, struct mvpp2_port, phylink_config);
> > > +}
> > > +
> > >  static void mvpp2_phylink_validate(struct phylink_config *config,
> > >                                    unsigned long *supported,
> > >                                    struct phylink_link_state *state)
> > >  {
> > > -       struct mvpp2_port *port = container_of(config, struct mvpp2_port,
> > > -                                              phylink_config);
> > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
> > >         __ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
> > >
> > >         /* Invalid combinations */
> > > @@ -4913,8 +4917,7 @@ static void mvpp2_gmac_pcs_get_state(struct mvpp2_port *port,
> > >  static void mvpp2_phylink_mac_pcs_get_state(struct phylink_config *config,
> > >                                             struct phylink_link_state *state)
> > >  {
> > > -       struct mvpp2_port *port = container_of(config, struct mvpp2_port,
> > > -                                              phylink_config);
> > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
> > >
> > >         if (port->priv->hw_version == MVPP22 && port->gop_id == 0) {
> > >                 u32 mode = readl(port->base + MVPP22_XLG_CTRL3_REG);
> > > @@ -4931,8 +4934,7 @@ static void mvpp2_phylink_mac_pcs_get_state(struct phylink_config *config,
> > >
> > >  static void mvpp2_mac_an_restart(struct phylink_config *config)
> > >  {
> > > -       struct mvpp2_port *port = container_of(config, struct mvpp2_port,
> > > -                                              phylink_config);
> > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
> > >         u32 val = readl(port->base + MVPP2_GMAC_AUTONEG_CONFIG);
> > >
> > >         writel(val | MVPP2_GMAC_IN_BAND_RESTART_AN,
> > > @@ -5105,13 +5107,12 @@ static void mvpp2_gmac_config(struct mvpp2_port *port, unsigned int mode,
> > >  static void mvpp2_mac_config(struct phylink_config *config, unsigned int mode,
> > >                              const struct phylink_link_state *state)
> > >  {
> > > -       struct net_device *dev = to_net_dev(config->dev);
> > > -       struct mvpp2_port *port = netdev_priv(dev);
> > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
> > >         bool change_interface = port->phy_interface != state->interface;
> > >
> > >         /* Check for invalid configuration */
> > >         if (mvpp2_is_xlg(state->interface) && port->gop_id != 0) {
> > > -               netdev_err(dev, "Invalid mode on %s\n", dev->name);
> > > +               netdev_err(port->dev, "Invalid mode on %s\n", port->dev->name);
> > >                 return;
> > >         }
> > >
> > > @@ -5151,8 +5152,7 @@ static void mvpp2_mac_link_up(struct phylink_config *config,
> > >                               int speed, int duplex,
> > >                               bool tx_pause, bool rx_pause)
> > >  {
> > > -       struct net_device *dev = to_net_dev(config->dev);
> > > -       struct mvpp2_port *port = netdev_priv(dev);
> > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
> > >         u32 val;
> > >
> > >         if (mvpp2_is_xlg(interface)) {
> > > @@ -5199,14 +5199,13 @@ static void mvpp2_mac_link_up(struct phylink_config *config,
> > >
> > >         mvpp2_egress_enable(port);
> > >         mvpp2_ingress_enable(port);
> > > -       netif_tx_wake_all_queues(dev);
> > > +       netif_tx_wake_all_queues(port->dev);
> > >  }
> > >
> > >  static void mvpp2_mac_link_down(struct phylink_config *config,
> > >                                 unsigned int mode, phy_interface_t interface)
> > >  {
> > > -       struct net_device *dev = to_net_dev(config->dev);
> > > -       struct mvpp2_port *port = netdev_priv(dev);
> > > +       struct mvpp2_port *port = mvpp2_phylink_to_port(config);
> > >         u32 val;
> > >
> > >         if (!phylink_autoneg_inband(mode)) {
> > > @@ -5223,7 +5222,7 @@ static void mvpp2_mac_link_down(struct phylink_config *config,
> > >                 }
> > >         }
> > >
> > > -       netif_tx_stop_all_queues(dev);
> > > +       netif_tx_stop_all_queues(port->dev);
> > >         mvpp2_egress_disable(port);
> > >         mvpp2_ingress_disable(port);
> > >
> > > --
> > > 2.20.1
> > >
> >
> > This patch fixes a regression that was introduced in v5.3:
> > Commit 44cc27e43fa3 ("net: phylink: Add struct phylink_config to PHYLINK API")
> >
> > Above results in a NULL pointer dereference when booting the
> > Armada7k8k/CN913x with ACPI between 5.3 and 5.8, which will be
> > problematic especially for the distros using LTSv5.4 and above (the
> > issue was reported on Fedora 32).
> >
> > Please help with backporting to the stable v5.3+ branches (it applies
> > smoothly on v5.4/v5.6/v5.8).
> 
> Any chances to backport this patch to relevant v5.3+ stable branches?

Who are you asking to do the backport? I guess you're asking me to
backport it, but I don't generally follow the stable kernels, and
I don't use ACPI on ARM systems, so I wouldn't be in a position to
test that a backported version fixes the problem you are reporting.

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