[PATCH net] i40e: fix netdev leak in i40e_vsi_setup() error paths

[Dawei Feng <dawei.feng@seu.edu.cn>]

i40e_config_netdev() allocates vsi->netdev for main and VMDQ VSIs. If
i40e_netif_set_realnum_tx_rx_queues(), i40e_devlink_create_port(), or
register_netdev() fails, i40e_vsi_setup() goes to err_netdev without
releasing the netdev. The existing cleanup only frees the netdev after a
successful register_netdev(), so these error paths leak the allocation.

Reorder the error paths at err_netdev to ensure proper cleanup of the
allocated device.

The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still
present in v7.1-rc5.

An x86_64 allyesconfig build showed no new warnings. As we do not have an
Intel Ethernet Controller XL710 family adapter to test with, no runtime
testing was able to be performed.

Fixes: 41c445ff0f48 ("i40e: main driver core")
Cc: stable@vger.kernel.org

Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 6d4f9218dc68..1ced01b0cc09 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -14491,13 +14491,15 @@ struct i40e_vsi *i40e_vsi_setup(struct i40e_pf *pf, u8 type,
 	if (vsi->netdev_registered) {
 		vsi->netdev_registered = false;
 		unregister_netdev(vsi->netdev);
-		free_netdev(vsi->netdev);
-		vsi->netdev = NULL;
 	}
 err_dl_port:
 	if (vsi->type == I40E_VSI_MAIN)
 		i40e_devlink_destroy_port(pf);
 err_netdev:
+	if (vsi->netdev) {
+		free_netdev(vsi->netdev);
+		vsi->netdev = NULL;
+	}
 	i40e_aq_delete_element(&pf->hw, vsi->seid, NULL);
 err_vsi:
 	i40e_vsi_clear(vsi);
-- 
2.34.1