[PATCH net v2] ice: fix memory leak in ice_lbtest_prepare_rings()

[Dawei Feng]

ice_lbtest_prepare_rings() frees Rx rings only when
ice_vsi_start_all_rx_rings() fails. If ice_vsi_setup_rx_rings() fails
after allocating some descriptors, or if ice_vsi_cfg_lan() fails after
the Rx rings were prepared, the function reaches the Tx cleanup path
without releasing the initialized Rx resources.

Fix this by adding separate unwind paths for Rx setup failure and LAN
configuration failure. The Rx setup failure path releases the partially
prepared Rx rings before freeing Tx rings, while later failures first
undo the LAN Tx configuration and then release the Rx rings in reverse
setup order.

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 E800 Series adapter available to run the ethtool offline loopback
selftest, no runtime testing was able to be performed.

Fixes: 0e674aeb0b77 ("ice: Add handler for ethtool selftest")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Zilin Guan <zilin@xxxxxxxxxx>
Signed-off-by: Dawei Feng <dawei.feng@xxxxxxxxxx>
---
Changes in v2:
- Fix cleanup order

 drivers/net/ethernet/intel/ice/ice_ethtool.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
index f28416a707d7..10a4abc66974 100644
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -1069,18 +1069,18 @@ static int ice_lbtest_prepare_rings(struct ice_vsi *vsi)
 
 	status = ice_vsi_cfg_lan(vsi);
 	if (status)
-		goto err_setup_rx_ring;
+		goto err_cfg_lan;
 
 	status = ice_vsi_start_all_rx_rings(vsi);
 	if (status)
-		goto err_start_rx_ring;
+		goto err_cfg_lan;
 
 	return 0;
 
-err_start_rx_ring:
-	ice_vsi_free_rx_rings(vsi);
-err_setup_rx_ring:
+err_cfg_lan:
 	ice_vsi_stop_lan_tx_rings(vsi, ICE_NO_RESET, 0);
+err_setup_rx_ring:
+	ice_vsi_free_rx_rings(vsi);
 err_setup_tx_ring:
 	ice_vsi_free_tx_rings(vsi);
 
-- 
2.34.1