On Tue, Jun 30, 2026 at 09:53:20AM -0700, Zhiping Zhang wrote:

Workloads that repeatedly allocate and release mkeys carrying TPH
steering-tag hints (e.g. churning RDMA MRs) leak one
struct mlx5_st_idx_data per cycle; kmemleak flags it as unreferenced
and the kmalloc slab grows over time.

When the last reference to an ST table entry is dropped,
mlx5_st_dealloc_index() removed the entry from idx_xa but the backing
mlx5_st_idx_data allocation was never freed.

Free idx_data after the xa_erase() so the lifetime of the bookkeeping
struct matches the lifetime of the ST entry it tracks.

Cc: stable@vger.kernel.org
Fixes: 888a7776f4fb ("net/mlx5: Add support for device steering tag")
Reviewed-by: Michael Gur <redacted>
Signed-off-by: Zhiping Zhang <redacted>
---
v2: respin per maintainer-netdev.rst; no code change.
v1: https://lore.kernel.org/linux-rdma/20260612170406.3339093-1-zhipingz@meta.com/ (local)

 drivers/net/ethernet/mellanox/mlx5/core/lib/st.c | 1 +
 1 file changed, 1 insertion(+)

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>