Re: [PATCH 3/4] perf tools: Copy metric events properly when expand cgroups

From: Jiri Olsa <jolsa@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Stephane Eranian <eranian@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Andi Kleen <ak@linux.intel.com>, Ian Rogers <irogers@google.com>,
	John Garry <john.garry@huawei.com>,
	Kajol Jain <kjain@linux.ibm.com>
Subject: Re: [PATCH 3/4] perf tools: Copy metric events properly when expand cgroups
Date: Fri, 18 Sep 2020 15:45:35 +0200	[thread overview]
Message-ID: <20200918134535.GC2626435@krava> (raw)
In-Reply-To: <20200916063129.1061487-4-namhyung@kernel.org>

On Wed, Sep 16, 2020 at 03:31:28PM +0900, Namhyung Kim wrote:

SNIP

> +					free(new_expr);
> +					return -ENOMEM;
> +				}
> +
> +				memcpy(new_expr->metric_refs, old_expr->metric_refs,
> +				       nr * alloc_size);
> +			} else {
> +				new_expr->metric_refs = NULL;
> +			}
> +
> +			/* calculate number of metric_events */
> +			for (nr = 0; old_expr->metric_events[nr]; nr++)
> +				continue;
> +			alloc_size = sizeof(*new_expr->metric_events);
> +			new_expr->metric_events = calloc(nr + 1, alloc_size);
> +			if (!new_expr->metric_events) {
> +				free(new_expr->metric_refs);
> +				free(new_expr);
> +				return -ENOMEM;
> +			}
> +
> +			/* copy evsel in the same position */
> +			for (idx = 0; idx < nr; idx++) {
> +				evsel = old_expr->metric_events[idx];
> +				evsel = evlist__get_evsel(evlist, evsel->idx);

this probably won't happen, but evlist__get_evsel can return NULL

jirka

> +				new_expr->metric_events[idx] = evsel;
> +			}
> +
> +			list_add(&new_expr->nd, &new_me->head);
> +		}
> +	}
> +	return 0;
> +}

SNIP