Re: [PATCH 2/2] perf metricgroup: Return error code from metricgroup__add_metric_sys_event_iter()
From: Ian Rogers <irogers@google.com>
Date: 2021-06-10 18:46:50
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On Thu, Jun 10, 2021 at 7:37 AM John Garry [off-list ref] wrote:
The error code is not set at all in the sys event iter function.
This may lead to an uninitialized value of "ret" in
metricgroup__add_metric() when no CPU metric is added.
Fix by properly setting the error code.
It is not necessary to init "ret" to 0 in metricgroup__add_metric(), as
if we have no CPU or sys event metric matching, then "has_match" should
be 0 and "ret" is set to -EINVAL.
However gcc cannot detect that it may not have been set after the
map_for_each_metric() loop for CPU metrics, which is strange.
Fixes: be335ec28efa8 ("perf metricgroup: Support adding metrics for system PMUs")
Signed-off-by: John Garry <redacted>Acked-by: Ian Rogers <irogers@google.com> Thanks, Ian
quoted hunk ↗ jump to hunk
--- tools/perf/util/metricgroup.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c index c456fdeae06a..d3cf2dee36c8 100644 --- a/tools/perf/util/metricgroup.c +++ b/tools/perf/util/metricgroup.c@@ -1073,16 +1073,18 @@ static int metricgroup__add_metric_sys_event_iter(struct pmu_event *pe, ret = add_metric(d->metric_list, pe, d->metric_no_group, &m, NULL, d->ids); if (ret) - return ret; + goto out; ret = resolve_metric(d->metric_no_group, d->metric_list, NULL, d->ids); if (ret) - return ret; + goto out; *(d->has_match) = true; - return *d->ret; +out: + *(d->ret) = ret; + return ret; } static int metricgroup__add_metric(const char *metric, bool metric_no_group, --2.26.2