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

Marcin Wojtas
2020-12-08T15:03:50Z

Hi Sasha,

wt., 8 gru 2020 o 14:35 Sasha Levin <sashal@kernel.org> napisał(a):
>
> On Tue, Dec 08, 2020 at 01:03:38PM +0100, Marcin Wojtas wrote:
> >Hi Greg,
> >
> >Apologies for delayed response:.
> >
> >
> >pon., 2 lis 2020 o 19:02 Greg Kroah-Hartman
> ><gregkh@linuxfoundation.org> napisał(a):
> >>
> >> 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 <mw@semihalf.com> napisał(a):
> >> > >
> >> > > Hi,
> >> > >
> >> > > sob., 20 cze 2020 o 11:21 Russell King <rmk+kernel@armlinux.org.uk> 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 <rmk+kernel@armlinux.org.uk>
> >> > > > ---
> >> > > > .../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?
> >>
> >> What patch? What git commit id needs to be backported?
> >>
> >
> >The actual patch is:
> >Commit 6c2b49eb9671 ("net: mvpp2: add mvpp2_phylink_to_port() helper").
> >
> >URL for reference:
> >https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/ethernet/marvell/mvpp2?h=v5.10-rc7&id=6c2b49eb96716e91f202756bfbd3f5fea3b2b172
> >
> >Do you think it would be possible to get it merged to v5.3+ stable branches?
>
> Could you explain how that patch fixes anything? It reads like a
> cleanup.
>

Indeed, I am aware of it, but I'm not sure about the best way to fix
it. In fact the mentioned patch is an unintentional fix. Commit
44cc27e43fa3 ("net: phylink: Add struct phylink_config to PHYLINK
API") reworked an argument list of mvpp2_mac_config() routine in a way
that resulted in a NULL pointer dereference when booting the
Armada7k8k/CN913x with ACPI between 5.3 and 5.8. Part of Russell's
patch resolves this issue.

What is the best way to handle that?

Thanks,
Marcin