[PATCH net-next v1 4/4] net/mlx5: HWS, Don't free the send ring CQ buffer if destroying the CQ fails

[Yuho Choi]

hws_send_ring_close_cq() ignores the result of mlx5_core_destroy_cq()
and frees the CQ buffer and doorbell record with mlx5_wq_destroy()
anyway. If DESTROY_CQ fails, the CQ may still exist in firmware and
retain access to that memory after it has been returned to the
allocator.

Leak the buffer instead when the CQ cannot be destroyed. A device in
internal error is not affected, since the mlx5 core reports success for
DESTROY_CQ in that state.

Fixes: 2ca62599aa0b ("net/mlx5: HWS, added send engine and context handling")
Assisted-by: LLM
Signed-off-by: Yuho Choi <oss.patchbox@xxxxxxxxx>
---
This was found with a static analysis tool from ongoing, not yet
published research, and confirmed by code inspection. It has not been
reproduced on hardware.

 drivers/net/ethernet/mellanox/mlx5/core/steering/hws/send.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/send.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/send.c
index df3b93499eebb..21e2d0a26e88a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/send.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/send.c
@@ -1005,7 +1005,9 @@ static int hws_send_ring_open_cq(struct mlx5_core_dev *mdev,
 
 static void hws_send_ring_close_cq(struct mlx5hws_send_ring_cq *cq)
 {
-	mlx5_core_destroy_cq(cq->mdev, &cq->mcq);
+	/* A CQ that was not destroyed can still access its buffer, leak it */
+	if (mlx5_core_destroy_cq(cq->mdev, &cq->mcq))
+		return;
 	mlx5_wq_destroy(&cq->wq_ctrl);
 }
 
-- 
2.43.0