cxgb4/cxgb4vf: Fix mac_hlist initialization and free

Null pointer dereference seen when cxgb4vf driver is unloaded
without bringing up any interfaces, moving mac_hlist initialization
to driver probe and free the mac_hlist in remove to fix the issue.

Fixes: 24357e06 ("cxgb4vf: fix memleak in mac_hlist initialization")
Signed-off-by: Arjun Vynipadath <arjun@chelsio.com>
Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -2280,8 +2280,6 @@ static int cxgb_up(struct adapter *adap)
 #if IS_ENABLED(CONFIG_IPV6)
 	update_clip(adap);
 #endif
-	/* Initialize hash mac addr list*/
-	INIT_LIST_HEAD(&adap->mac_hlist);
 	return err;
 
  irq_err:
@@ -2295,8 +2293,6 @@ static int cxgb_up(struct adapter *adap)
 
 static void cxgb_down(struct adapter *adapter)
 {
-	struct hash_mac_addr *entry, *tmp;
-
 	cancel_work_sync(&adapter->tid_release_task);
 	cancel_work_sync(&adapter->db_full_task);
 	cancel_work_sync(&adapter->db_drop_task);
@@ -2306,11 +2302,6 @@ static void cxgb_down(struct adapter *adapter)
 	t4_sge_stop(adapter);
 	t4_free_sge_resources(adapter);
 
-	list_for_each_entry_safe(entry, tmp, &adapter->mac_hlist, list) {
-		list_del(&entry->list);
-		kfree(entry);
-	}
-
 	adapter->flags &= ~FULL_INIT_DONE;
 }
 
@@ -5629,6 +5620,9 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 			     (is_t5(adapter->params.chip) ? STATMODE_V(0) :
 			      T6_STATMODE_V(0)));
 
+	/* Initialize hash mac addr list */
+	INIT_LIST_HEAD(&adapter->mac_hlist);
+
 	for_each_port(adapter, i) {
 		netdev = alloc_etherdev_mq(sizeof(struct port_info),
 					   MAX_ETH_QSETS);
@@ -5907,6 +5901,7 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 static void remove_one(struct pci_dev *pdev)
 {
 	struct adapter *adapter = pci_get_drvdata(pdev);
+	struct hash_mac_addr *entry, *tmp;
 
 	if (!adapter) {
 		pci_release_regions(pdev);
@@ -5956,6 +5951,12 @@ static void remove_one(struct pci_dev *pdev)
 		if (adapter->num_uld || adapter->num_ofld_uld)
 			t4_uld_mem_free(adapter);
 		free_some_resources(adapter);
+		list_for_each_entry_safe(entry, tmp, &adapter->mac_hlist,
+					 list) {
+			list_del(&entry->list);
+			kfree(entry);
+		}
+
 #if IS_ENABLED(CONFIG_IPV6)
 		t4_cleanup_clip_tbl(adapter);
 #endif

drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c

@@ -723,9 +723,6 @@ static int adapter_up(struct adapter *adapter)
 		if (adapter->flags & USING_MSIX)
 			name_msix_vecs(adapter);
 
-		/* Initialize hash mac addr list*/
-		INIT_LIST_HEAD(&adapter->mac_hlist);
-
 		adapter->flags |= FULL_INIT_DONE;
 	}
 
@@ -3038,6 +3035,9 @@ static int cxgb4vf_pci_probe(struct pci_dev *pdev,
 	if (err)
 		goto err_unmap_bar;
 
+	/* Initialize hash mac addr list */
+	INIT_LIST_HEAD(&adapter->mac_hlist);
+
 	/*
 	 * Allocate our "adapter ports" and stitch everything together.
 	 */