net: mscc: ocelot: fix error handling bugs in mscc_ocelot_init_ports()

There are several error handling bugs in mscc_ocelot_init_ports().  I
went through the code, and carefully audited it and made fixes and
cleanups.

1) The ocelot_probe_port() function didn't have a mirror release function
   so it was hard to follow.  I created the ocelot_release_port()
   function.
2) In the ocelot_probe_port() function, if the register_netdev() call
   failed, then it lead to a double free_netdev(dev) bug.  Fix this by
   setting "ocelot->ports[port] = NULL" on the error path.
3) I was concerned that the "port" which comes from of_property_read_u32()
   might be out of bounds so I added a check for that.
4) In the original code if ocelot_regmap_init() failed then the driver
   tried to continue but I think that should be a fatal error.
5) If ocelot_probe_port() failed then the most recent devlink was leaked.
   The fix for mostly came Vladimir Oltean.  Get rid of "registered_ports"
   and just set a bit in "devlink_ports_registered" to say when the
   devlink port has been registered (and needs to be unregistered on
   error).  There are fewer than 32 ports so a u32 is large enough for
   this purpose.
6) The error handling if the final ocelot_port_devlink_init() failed had
   two problems.  The "while (port-- >= 0)" loop should have been
   "--port" pre-op instead of a post-op to avoid a buffer underflow.
   The "if (!registered_ports[port])" condition was reversed leading to
   resource leaks and double frees.

Fixes: 6c30384eb1de ("net: mscc: ocelot: register devlink ports")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/YBkXhqRxHtRGzSnJ@mwanda
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/mscc/ocelot.h b/drivers/net/ethernet/mscc/ocelot.h
index e8621db..76b8d8c 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot.h
+++ b/drivers/net/ethernet/mscc/ocelot.h
@@ -121,6 +121,7 @@ void ocelot_port_writel(struct ocelot_port *port, u32 val, u32 reg);
 
 int ocelot_probe_port(struct ocelot *ocelot, int port, struct regmap *target,
                      struct phy_device *phy);
+void ocelot_release_port(struct ocelot_port *ocelot_port);
 int ocelot_devlink_init(struct ocelot *ocelot);
 void ocelot_devlink_teardown(struct ocelot *ocelot);
 int ocelot_port_devlink_init(struct ocelot *ocelot, int port,

diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c
index 0514280..e6b33d9 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot_net.c
+++ b/drivers/net/ethernet/mscc/ocelot_net.c
@@ -1283,7 +1283,19 @@ int ocelot_probe_port(struct ocelot *ocelot, int port, struct regmap *target,
        if (err) {
                dev_err(ocelot->dev, "register_netdev failed\n");
                free_netdev(dev);
+               ocelot->ports[port] = NULL;
+               return err;
        }
 
-       return err;
+       return 0;
+}
+
+void ocelot_release_port(struct ocelot_port *ocelot_port)
+{
+       struct ocelot_port_private *priv = container_of(ocelot_port,
+                                               struct ocelot_port_private,
+                                               port);
+
+       unregister_netdev(priv->dev);
+       free_netdev(priv->dev);
 }

diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
index 407244f..b52e248 100644 (file)
--- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c
+++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
@@ -1064,7 +1064,6 @@ static void mscc_ocelot_release_ports(struct ocelot *ocelot)
        int port;
 
        for (port = 0; port < ocelot->num_phys_ports; port++) {
-               struct ocelot_port_private *priv;
                struct ocelot_port *ocelot_port;
 
                ocelot_port = ocelot->ports[port];
@@ -1072,12 +1071,7 @@ static void mscc_ocelot_release_ports(struct ocelot *ocelot)
                        continue;
 
                ocelot_deinit_port(ocelot, port);
-
-               priv = container_of(ocelot_port, struct ocelot_port_private,
-                                   port);
-
-               unregister_netdev(priv->dev);
-               free_netdev(priv->dev);
+               ocelot_release_port(ocelot_port);
        }
 }
 
@@ -1085,8 +1079,8 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
                                  struct device_node *ports)
 {
        struct ocelot *ocelot = platform_get_drvdata(pdev);
+       u32 devlink_ports_registered = 0;
        struct device_node *portnp;
-       bool *registered_ports;
        int port, err;
        u32 reg;
 
@@ -1102,11 +1096,6 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
        if (!ocelot->devlink_ports)
                return -ENOMEM;
 
-       registered_ports = kcalloc(ocelot->num_phys_ports, sizeof(bool),
-                                  GFP_KERNEL);
-       if (!registered_ports)
-               return -ENOMEM;
-
        for_each_available_child_of_node(ports, portnp) {
                struct ocelot_port_private *priv;
                struct ocelot_port *ocelot_port;
@@ -1123,14 +1112,22 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
                        continue;
 
                port = reg;
+               if (port < 0 || port >= ocelot->num_phys_ports) {
+                       dev_err(ocelot->dev,
+                               "invalid port number: %d >= %d\n", port,
+                               ocelot->num_phys_ports);
+                       continue;
+               }
 
                snprintf(res_name, sizeof(res_name), "port%d", port);
 
                res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
                                                   res_name);
                target = ocelot_regmap_init(ocelot, res);
-               if (IS_ERR(target))
-                       continue;
+               if (IS_ERR(target)) {
+                       err = PTR_ERR(target);
+                       goto out_teardown;
+               }
 
                phy_node = of_parse_phandle(portnp, "phy-handle", 0);
                if (!phy_node)
@@ -1147,6 +1144,7 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
                        of_node_put(portnp);
                        goto out_teardown;
                }
+               devlink_ports_registered |= BIT(port);
 
                err = ocelot_probe_port(ocelot, port, target, phy);
                if (err) {
@@ -1154,8 +1152,6 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
                        goto out_teardown;
                }
 
-               registered_ports[port] = true;
-
                ocelot_port = ocelot->ports[port];
                priv = container_of(ocelot_port, struct ocelot_port_private,
                                    port);
@@ -1208,23 +1204,16 @@ static int mscc_ocelot_init_ports(struct platform_device *pdev,
 
        /* Initialize unused devlink ports at the end */
        for (port = 0; port < ocelot->num_phys_ports; port++) {
-               if (registered_ports[port])
+               if (devlink_ports_registered & BIT(port))
                        continue;
 
                err = ocelot_port_devlink_init(ocelot, port,
                                               DEVLINK_PORT_FLAVOUR_UNUSED);
-               if (err) {
-                       while (port-- >= 0) {
-                               if (!registered_ports[port])
-                                       continue;
-                               ocelot_port_devlink_teardown(ocelot, port);
-                       }
-
+               if (err)
                        goto out_teardown;
-               }
-       }
 
-       kfree(registered_ports);
+               devlink_ports_registered |= BIT(port);
+       }
 
        return 0;
 
@@ -1233,12 +1222,9 @@ out_teardown:
        mscc_ocelot_release_ports(ocelot);
        /* Tear down devlink ports for the registered network interfaces */
        for (port = 0; port < ocelot->num_phys_ports; port++) {
-               if (!registered_ports[port])
-                       continue;
-
-               ocelot_port_devlink_teardown(ocelot, port);
+               if (devlink_ports_registered & BIT(port))
+                       ocelot_port_devlink_teardown(ocelot, port);
        }
-       kfree(registered_ports);
        return err;
 }