net: dsa: Add error path handling in dsa_tree_setup()

In case a call to dsa_tree_setup() fails, an attempt to cleanup is made
by calling dsa_tree_remove_switch(), which should take care of
removing/unregistering any resources previously allocated. This does not
happen because it is conditioned by dst->setup being true, which is set
only after _all_ setup steps were performed successfully.

This is especially interesting when the internal MDIO bus is registered
but afterwards, a port setup fails and the mdiobus_unregister() is never
called. This leads to a BUG_ON() complaining about the fact that it's
trying to free an MDIO bus that's still registered.

Add proper error handling in all functions branching from
dsa_tree_setup().

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 66 insertions, 23 deletions

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 3b5f434cad3f..b70befe8a3c8 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -261,7 +261,7 @@ static int dsa_port_setup(struct dsa_port *dp)
         enum devlink_port_flavour flavour;
         struct dsa_switch *ds = dp->ds;
         struct dsa_switch_tree *dst = ds->dst;
-        int err;
+        int err = 0;
 
         if (dp->type == DSA_PORT_TYPE_UNUSED)
                 return 0;
@@ -299,19 +299,15 @@ static int dsa_port_setup(struct dsa_port *dp)
                 break;
         case DSA_PORT_TYPE_CPU:
                 err = dsa_port_link_register_of(dp);
-                if (err) {
+                if (err)
                         dev_err(ds->dev, "failed to setup link for port %d.%d\n",
                                 ds->index, dp->index);
-                        return err;
-                }
                 break;
         case DSA_PORT_TYPE_DSA:
                 err = dsa_port_link_register_of(dp);
-                if (err) {
+                if (err)
                         dev_err(ds->dev, "failed to setup link for port %d.%d\n",
                                 ds->index, dp->index);
-                        return err;
-                }
                 break;
         case DSA_PORT_TYPE_USER:
                 err = dsa_slave_create(dp);
@@ -323,7 +319,10 @@ static int dsa_port_setup(struct dsa_port *dp)
                 break;
         }
 
-        return 0;
+        if (err)
+                devlink_port_unregister(&dp->devlink_port);
+
+        return err;
 }
 
 static void dsa_port_teardown(struct dsa_port *dp)
@@ -351,7 +350,7 @@ static void dsa_port_teardown(struct dsa_port *dp)
 
 static int dsa_switch_setup(struct dsa_switch *ds)
 {
-        int err;
+        int err = 0;
 
         /* Initialize ds->phys_mii_mask before registering the slave MDIO bus
          * driver and before ops->setup() has run, since the switch drivers and
@@ -369,29 +368,41 @@ static int dsa_switch_setup(struct dsa_switch *ds)
 
         err = devlink_register(ds->devlink, ds->dev);
         if (err)
-                return err;
+                goto free_devlink;
 
         err = dsa_switch_register_notifier(ds);
         if (err)
-                return err;
+                goto unregister_devlink;
 
         err = ds->ops->setup(ds);
         if (err < 0)
-                return err;
+                goto unregister_notifier;
 
         if (!ds->slave_mii_bus && ds->ops->phy_read) {
                 ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
-                if (!ds->slave_mii_bus)
-                        return -ENOMEM;
+                if (!ds->slave_mii_bus) {
+                        err = -ENOMEM;
+                        goto unregister_notifier;
+                }
 
                 dsa_slave_mii_bus_init(ds);
 
                 err = mdiobus_register(ds->slave_mii_bus);
                 if (err < 0)
-                        return err;
+                        goto unregister_notifier;
         }
 
         return 0;
+
+unregister_notifier:
+        dsa_switch_unregister_notifier(ds);
+unregister_devlink:
+        devlink_unregister(ds->devlink);
+free_devlink:
+        devlink_free(ds->devlink);
+        ds->devlink = NULL;
+
+        return err;
 }
 
 static void dsa_switch_teardown(struct dsa_switch *ds)
@@ -413,8 +424,8 @@ static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
 {
         struct dsa_switch *ds;
         struct dsa_port *dp;
-        int device, port;
-        int err;
+        int device, port, i;
+        int err = 0;
 
         for (device = 0; device < DSA_MAX_SWITCHES; device++) {
                 ds = dst->ds[device];
@@ -423,18 +434,41 @@ static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
 
                 err = dsa_switch_setup(ds);
                 if (err)
-                        return err;
+                        goto switch_teardown;
 
                 for (port = 0; port < ds->num_ports; port++) {
                         dp = &ds->ports[port];
 
                         err = dsa_port_setup(dp);
                         if (err)
-                                return err;
+                                goto ports_teardown;
                 }
         }
 
         return 0;
+
+ports_teardown:
+        for (i = 0; i < port; i++)
+                dsa_port_teardown(&ds->ports[i]);
+
+        dsa_switch_teardown(ds);
+
+switch_teardown:
+        for (i = 0; i < device; i++) {
+                ds = dst->ds[i];
+                if (!ds)
+                        continue;
+
+                for (port = 0; port < ds->num_ports; port++) {
+                        dp = &ds->ports[port];
+
+                        dsa_port_teardown(dp);
+                }
+
+                dsa_switch_teardown(ds);
+        }
+
+        return err;
 }
 
 static void dsa_tree_teardown_switches(struct dsa_switch_tree *dst)
@@ -496,17 +530,24 @@ static int dsa_tree_setup(struct dsa_switch_tree *dst)
 
         err = dsa_tree_setup_switches(dst);
         if (err)
-                return err;
+                goto teardown_default_cpu;
 
         err = dsa_tree_setup_master(dst);
         if (err)
-                return err;
+                goto teardown_switches;
 
         dst->setup = true;
 
         pr_info("DSA: tree %d setup\n", dst->index);
 
         return 0;
+
+teardown_switches:
+        dsa_tree_teardown_switches(dst);
+teardown_default_cpu:
+        dsa_tree_teardown_default_cpu(dst);
+
+        return err;
 }
 
 static void dsa_tree_teardown(struct dsa_switch_tree *dst)
@@ -547,8 +588,10 @@ static int dsa_tree_add_switch(struct dsa_switch_tree *dst,
         dst->ds[index] = ds;
 
         err = dsa_tree_setup(dst);
-        if (err)
-                dsa_tree_remove_switch(dst, index);
+        if (err) {
+                dst->ds[index] = NULL;
+                dsa_tree_put(dst);
+        }
 
         return err;
 }