[PATCH 6.12.y 2/2] net/mlx5: HWS, fix matcher leak on resize target setup failure

[Sasha Levin <sashal@kernel.org>]

From: Dawei Feng <dawei.feng@seu.edu.cn>

[ Upstream commit bb09d0e64ecaa0aa0f7d1133a1696ed74dead295 ]

hws_bwc_matcher_move() allocates a replacement matcher before setting it
as the resize target. If mlx5hws_matcher_resize_set_target() fails, the
replacement matcher is not attached anywhere and is leaked.

Fix the leak by destroying the replacement matcher before returning from
the resize-target failure path.

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 v7.1.1.

An x86_64 allyesconfig build showed no new warnings. As we do not have a
mlx5 HWS-capable device to test with, no runtime testing was able to be
performed.

Fixes: 2111bb970c78 ("net/mlx5: HWS, added backward-compatible API handling")
Cc: stable@vger.kernel.org
Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>
Reviewed-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260629064049.3852759-1-dawei.feng@seu.edu.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c   | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c
index 3fc3ada0166534..4fdffc20cd7829 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/mlx5hws_bwc.c
@@ -225,6 +225,7 @@ static int hws_bwc_matcher_move(struct mlx5hws_bwc_matcher *bwc_matcher)
 	ret = mlx5hws_matcher_resize_set_target(old_matcher, new_matcher);
 	if (ret) {
 		mlx5hws_err(ctx, "Rehash error: failed setting resize target\n");
+		mlx5hws_matcher_destroy(new_matcher);
 		return ret;
 	}
 
-- 
2.53.0