[PATCH 1/1] perf,tools: error out unsupported group leader immediately for perf stat

[kan.liang@intel.com]

From: Kan Liang <kan.liang@intel.com>

perf stat ignores the unsupported event and continue to count supported
event. But if the unsupported event is group leader, perf tool will
crash. After applying this patch, the unsupported group leader will
error out immediately.

Without this patch:
$ perf stat -x, -e '{node-prefetch-refs,cycles}' --  sleep 1
perf: util/evsel.c:1009: get_group_fd: Assertion `!(fd == -1)' failed.
Aborted (core dumped)

With this patch:
$ perf stat -x, -e '{node-prefetch-refs,cycles}' --  sleep 1
Error:
The node-prefetch-refs event is not supported.

Signed-off-by: Kan Liang <kan.liang@intel.com>
---
 tools/perf/builtin-stat.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ff3d258..b24ecee 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -549,7 +549,10 @@ static int __run_perf_stat(int argc, const char **argv)
 					ui__warning("%s event is not supported by the kernel.\n",
 						    perf_evsel__name(counter));
 				counter->supported = false;
-				continue;
+
+				if ((counter->leader != counter) ||
+				    !(counter->leader->nr_members > 1))
+					continue;
 			}
 
 			perf_evsel__open_strerror(counter, &target,
-- 
1.8.3.1