[dpdk-stable] [PATCH 19.11 2/2] net/mlx5: fix hairpin Rx queue creation error flow

[Michael Baum]

[ upstream commit ebed623f621bbe9cf050a9eb7725f4d81cb95d4f ]

The mlx5_rxq_obj_hairpin_new function defines a pointer named tmpl and
allocates memory for it using the rte_zmalloc_socket function.
Later, this function allocates memory to a variable inside tmpl using
the mlx5_devx_cmd_create_rq function.

In both cases, if the allocation fails, the code jumps to the error
label and frees allocated resources. However, in the first jump there
are still no resources to free and the jump only for the line return
NULL is unnecessary. Even worse, when it jumps to error label with
invalid tmpl it actually does dereference to a null pointer.
In contrast, the second jump needs to free the tmpl variable but the
function instead of freeing, tries to free the variable that it just
failed to allocate.
In addition, for another error, the function returns NULL without
freeing the tmpl variable before, causing a memory leak.

Delete the error label and replace each jump with local return NULL and
free tmpl variable if needed.

Fixes: e79c9be91515 ("net/mlx5: support Rx hairpin queues")

Signed-off-by: Michael Baum <michaelba at mellanox.com>
Acked-by: Matan Azrad <matan at mellanox.com>
---
 drivers/net/mlx5/mlx5_rxq.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index 970ce5c..5a11325 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -1260,7 +1260,6 @@
 		container_of(rxq_data, struct mlx5_rxq_ctrl, rxq);
 	struct mlx5_devx_create_rq_attr attr = { 0 };
 	struct mlx5_rxq_obj *tmpl = NULL;
-	int ret = 0;
 	uint32_t max_wq_data;
 
 	assert(rxq_data);
@@ -1272,7 +1271,7 @@
 			"port %u Rx queue %u cannot allocate verbs resources",
 			dev->data->port_id, rxq_data->idx);
 		rte_errno = ENOMEM;
-		goto error;
+		return NULL;
 	}
 	tmpl->type = MLX5_RXQ_OBJ_TYPE_DEVX_HAIRPIN;
 	tmpl->rxq_ctrl = rxq_ctrl;
@@ -1292,8 +1291,9 @@
 		DRV_LOG(ERR,
 			"port %u Rx hairpin queue %u can't create rq object",
 			dev->data->port_id, idx);
+		rte_free(tmpl);
 		rte_errno = errno;
-		goto error;
+		return NULL;
 	}
 	DRV_LOG(DEBUG, "port %u rxq %u updated with %p", dev->data->port_id,
 		idx, (void *)&tmpl);
@@ -1301,12 +1301,6 @@
 	LIST_INSERT_HEAD(&priv->rxqsobj, tmpl, next);
 	priv->verbs_alloc_ctx.type = MLX5_VERBS_ALLOC_TYPE_NONE;
 	return tmpl;
-error:
-	ret = rte_errno; /* Save rte_errno before cleanup. */
-	if (tmpl->rq)
-		mlx5_devx_cmd_destroy(tmpl->rq);
-	rte_errno = ret; /* Restore rte_errno. */
-	return NULL;
 }
 
 /**
-- 
1.8.3.1