Re: [PATCH v10 00/21] futex: Add support task local hash maps, FUTEX2_NUMA and FUTEX2_MPOL

[Peter Zijlstra]

On Wed, Mar 12, 2025 at 04:18:48PM +0100, Sebastian Andrzej Siewior wrote:

> @@ -1591,7 +1597,8 @@ static int futex_hash_allocate(unsigned int hash_slots, bool custom)
>  		struct futex_private_hash *free __free(kvfree) = NULL;
>  		struct futex_private_hash *cur, *new;
>  
> -		cur = mm->futex_phash;
> +		cur = rcu_dereference_protected(mm->futex_phash,
> +						lockdep_is_held(&mm->futex_hash_lock));
>  		new = mm->futex_phash_new;
>  		mm->futex_phash_new = NULL;
>  

Same thing again, this makes no sense.