Re: [BUG] uncore_pmu_event_init: using smp_processor_id() in preemptible core

[Peter Zijlstra <peterz@infradead.org>]

On Tue, Sep 17, 2013 at 12:58:34PM +0800, Yan, Zheng wrote:
> ---
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> index fd8011e..a12a22f 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> @@ -2713,7 +2713,10 @@ struct intel_uncore_box *uncore_alloc_box(struct intel_uncore_type *type, int cp
>  
>  	size = sizeof(*box) + type->num_shared_regs * sizeof(struct intel_uncore_extra_reg);
>  
> -	box = kzalloc_node(size, GFP_KERNEL, cpu_to_node(cpu));
> +	if (cpu < 0)
> +		box = kzalloc(size, GFP_KERNEL);
> +	else
> +		box = kzalloc_node(size, GFP_KERNEL, cpu_to_node(cpu));
>  	if (!box)
>  		return NULL;

I believe -1 is a valid node number for all allocators, in which case
they fall back to the current node.

>  
> @@ -3031,7 +3034,7 @@ static int uncore_validate_group(struct intel_uncore_pmu *pmu,
>  	struct intel_uncore_box *fake_box;
>  	int ret = -EINVAL, n;
>  
> -	fake_box = uncore_alloc_box(pmu->type, smp_processor_id());
> +	fake_box = uncore_alloc_box(pmu->type, -1);
>  	if (!fake_box)
>  		return -ENOMEM;
>  

Yes, much better indeed.