[PATCH 5.4 03/96] IB/mlx4: Fix memory leak in add_gid error flow

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>

commit eaad647e5cc27f7b46a27f3b85b14c4c8a64bffa upstream.

In procedure mlx4_ib_add_gid(), if the driver is unable to update the FW
gid table, there is a memory leak in the driver's copy of the gid table:
the gid entry's context buffer is not freed.

If such an error occurs, free the entry's context buffer, and mark the
entry as available (by setting its context pointer to NULL).

Fixes: e26be1bfef81 ("IB/mlx4: Implement ib_device callbacks")
Link: https://lore.kernel.org/r/20200115085050.73746-1-leon@xxxxxxxxxx
Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Parav Pandit <parav@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/hw/mlx4/main.c |   20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/hw/mlx4/main.c
+++ b/drivers/infiniband/hw/mlx4/main.c
@@ -246,6 +246,13 @@ static int mlx4_ib_update_gids(struct gi
 	return mlx4_ib_update_gids_v1(gids, ibdev, port_num);
 }
 
+static void free_gid_entry(struct gid_entry *entry)
+{
+	memset(&entry->gid, 0, sizeof(entry->gid));
+	kfree(entry->ctx);
+	entry->ctx = NULL;
+}
+
 static int mlx4_ib_add_gid(const struct ib_gid_attr *attr, void **context)
 {
 	struct mlx4_ib_dev *ibdev = to_mdev(attr->device);
@@ -306,6 +313,8 @@ static int mlx4_ib_add_gid(const struct
 				     GFP_ATOMIC);
 		if (!gids) {
 			ret = -ENOMEM;
+			*context = NULL;
+			free_gid_entry(&port_gid_table->gids[free]);
 		} else {
 			for (i = 0; i < MLX4_MAX_PORT_GIDS; i++) {
 				memcpy(&gids[i].gid, &port_gid_table->gids[i].gid, sizeof(union ib_gid));
@@ -317,6 +326,12 @@ static int mlx4_ib_add_gid(const struct
 
 	if (!ret && hw_update) {
 		ret = mlx4_ib_update_gids(gids, ibdev, attr->port_num);
+		if (ret) {
+			spin_lock_bh(&iboe->lock);
+			*context = NULL;
+			free_gid_entry(&port_gid_table->gids[free]);
+			spin_unlock_bh(&iboe->lock);
+		}
 		kfree(gids);
 	}
 
@@ -346,10 +361,7 @@ static int mlx4_ib_del_gid(const struct
 		if (!ctx->refcount) {
 			unsigned int real_index = ctx->real_index;
 
-			memset(&port_gid_table->gids[real_index].gid, 0,
-			       sizeof(port_gid_table->gids[real_index].gid));
-			kfree(port_gid_table->gids[real_index].ctx);
-			port_gid_table->gids[real_index].ctx = NULL;
+			free_gid_entry(&port_gid_table->gids[real_index]);
 			hw_update = 1;
 		}
 	}