Re: [PATCH net v2] net/mlx5e: IPOIB, Fix QPN lookup race

[Tariq Toukan]

On 01/11/2026 0:57, Prathamesh Deshpande wrote:
> The parent RX completion path can load a QPN hash entry before
> mlx5i_pkey_del_qpn() unlinks and frees it, then dereference freed memory.
>
> Use RCU hlist operations and defer freeing with kfree_rcu(). The existing
> RCU read-side section in mlx5e_napi_poll() covers the lookup. Keep ht_lock
> for writers and acquire it before looking up the entry to delete.
>
> Fixes: 7e7f4780c340 ("net/mlx5e: IPoIB, Use hash-table to map between QPN to child netdev")
> Signed-off-by: Prathamesh Deshpande <prathameshdeshpande7@xxxxxxxxx>
> ---
>
> Changes in v2:
> - Replace the RX spinlock with RCU traversal and deferred freeing.
> - Narrow the description to the parent CQE lookup race.
>
> v1: https://lore.kernel.org/all/20261030002241.8508-1-prathameshdeshpande7@xxxxxxxxx/
> Review: https://lore.kernel.org/all/ade46454-e575-43e4-85aa-eeb5ad79408a@xxxxxxxxxx/

nit: Convention is IPoIB, not IPOIB. Maybe can be modified while applying.

Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxx>

Thanks.