Re: [PATCH] sched: missing locking in sched_domains code

[Ingo Molnar <mingo@elte.hu>]

* Heiko Carstens <heiko.carstens@de.ibm.com> wrote:

>  
>  /*
> + * Protects against concurrent calls to detach_destroy_domains
> + * and arch_init_sched_domains.
> + */
> +static DEFINE_MUTEX(sched_domains_mutex);
> +
> +/*
>   * Partition sched domains as specified by the 'ndoms_new'
>   * cpumasks in the array doms_new[] of cpumasks. This compares
>   * doms_new[] to the current sched domain partitioning, doms_cur[].
> @@ -7756,7 +7762,8 @@ void partition_sched_domains(int ndoms_n
>  	int i, j;
>  
>  	lock_doms_cur();
> -
> +	mutex_lock(&sched_domains_mutex);

i might be missing something but why not make doms_cur_mutex locking 
unconditional and extend it to detach_destroy_domains() as well?

	Ingo