Re: [PATCH v2 net-next 1/3] perf, bpf: Add BPF support to all perf_event types

[Peter Zijlstra <peterz@infradead.org>]

On Thu, May 25, 2017 at 10:55:47PM -0700, Alexei Starovoitov wrote:

> +++ b/kernel/bpf/arraymap.c
> @@ -462,26 +462,22 @@ static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
>  
>  	event = perf_file->private_data;
>  	ee = ERR_PTR(-EINVAL);
> +	/* Per-task events are not supported */
> +	if (event->attach_state & PERF_ATTACH_TASK)
> +		goto err_out;
>  
>  	attr = perf_event_attrs(event);
>  	if (IS_ERR(attr) || attr->inherit)
>  		goto err_out;

> +	/* TRACEPOINT and BREAKPOINT not supported in perf_event_read_local */

I cannot find reason for this comment. That is, why would
perf_event_read_local() not support those two types?

> +	if (attr->type == PERF_TYPE_TRACEPOINT ||
> +	    attr->type == PERF_TYPE_BREAKPOINT)
> +		goto err_out;
>  
> +	ee = bpf_event_entry_gen(perf_file, map_file);
> +	if (ee)
> +		return ee;
> +	ee = ERR_PTR(-ENOMEM);
>  
>  err_out:
>  	fput(perf_file);