Re: [PATCH net v2] net/mlx5: free mlx5_st_idx_data on final dealloc

[Leon Romanovsky]

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@xxxxxxxxxxxxxxx
> Fixes: 888a7776f4fb ("net/mlx5: Add support for device steering tag")
> Reviewed-by: Michael Gur <michaelgur@xxxxxxxxxx>
> Signed-off-by: Zhiping Zhang <zhipingz@xxxxxxxx>
> ---
> v2: respin per maintainer-netdev.rst; no code change.
> v1: https://lore.kernel.org/linux-rdma/20260612170406.3339093-1-zhipingz@xxxxxxxx/
> 
>  drivers/net/ethernet/mellanox/mlx5/core/lib/st.c | 1 +
>  1 file changed, 1 insertion(+)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxx>