[PATCH AUTOSEL 5.1 104/219] perf evsel: Make perf_evsel__name() accept a NULL argument

Sasha Levin
2019-07-15T14:09:51Z

From: Arnaldo Carvalho de Melo <acme@redhat.com>

[ Upstream commit fdbdd7e8580eac9bdafa532746c865644d125e34 ]

In which case it simply returns "unknown", like when it can't figure out
the evsel->name value.

This makes this code more robust and fixes a problem in 'perf trace'
where a NULL evsel was being passed to a routine that only used the
evsel for printing its name when a invalid syscall id was passed.

Reported-by: Leo Yan <leo.yan@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-f30ztaasku3z935cn3ak3h53@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/evsel.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 966360844fff..7ca79cfe1aea 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -584,6 +584,9 @@ const char *perf_evsel__name(struct perf_evsel *evsel)
{
char bf[128];

+ if (!evsel)
+ goto out_unknown;
+
if (evsel->name)
return evsel->name;

@@ -620,7 +623,10 @@ const char *perf_evsel__name(struct perf_evsel *evsel)

evsel->name = strdup(bf);

- return evsel->name ?: "unknown";
+ if (evsel->name)
+ return evsel->name;
+out_unknown:
+ return "unknown";
}

const char *perf_evsel__group_name(struct perf_evsel *evsel)
--
2.20.1