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

[Leon Romanovsky <leon@kernel.org>]

On Fri, Jul 10, 2026 at 01:25:45PM +0200, Paolo Abeni wrote:
> On 7/3/26 12:24 AM, 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 <michaelgur@nvidia.com>
> > Signed-off-by: Zhiping Zhang <zhipingz@meta.com>
> @Leon, @Saeed, @Tariq: just in case this fell under the radar, it's
> waiting for your ack.

Tariq and I completed this on Jul 5 and Jul 6.

https://lore.kernel.org/linux-rdma/20260705141920.GI15188@unreal/
https://lore.kernel.org/linux-rdma/0bb37f75-c94a-4a10-b115-186b71daf14f@nvidia.com/

Thanks

> 
> Thanks,
> 
> Paolo
>