Re: [PATCH 01/10] perf/x86: Add warning on proper cpu during event's update

From: Peter Zijlstra <peterz@infradead.org>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	David Ahern <dsahern@gmail.com>, Andi Kleen <andi@firstfloor.org>,
	Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH 01/10] perf/x86: Add warning on proper cpu during event's update
Date: Mon, 28 Aug 2017 21:24:32 +0200	[thread overview]
Message-ID: <20170828192432.yufnjgylcayxvczs@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20170824162737.7813-2-jolsa@kernel.org>

On Thu, Aug 24, 2017 at 06:27:28PM +0200, Jiri Olsa wrote:
> Mark reported that we could actually call pmu->read on
> unscheduled event. I think it's good idea to keep a
> warning here to see if we've get it wrong again in
> future.
> 
> Reported-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

Yeah, no objection to this one.

Ack

> ---
>  arch/x86/events/core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> index af12e294caed..b8e394d9f7f2 100644
> --- a/arch/x86/events/core.c
> +++ b/arch/x86/events/core.c
> @@ -72,6 +72,8 @@ u64 x86_perf_event_update(struct perf_event *event)
>  	int idx = hwc->idx;
>  	u64 delta;
>  
> +	WARN_ON_ONCE(event->oncpu != smp_processor_id());
> +
>  	if (idx == INTEL_PMC_IDX_FIXED_BTS)
>  		return 0;
>  
> -- 
> 2.9.5
> 