Linux 5.9 introduced perf test case "Parse and process metrics" and on s390 this test case always dumps core:
[root@t35lp67 perf]# ./perf test -vvvv -F 67 67: Parse and process metrics : --- start --- metric expr inst_retired.any / cpu_clk_unhalted.thread for IPC parsing metric: inst_retired.any / cpu_clk_unhalted.thread Segmentation fault (core dumped) [root@t35lp67 perf]# I debugged this core dump and gdb shows this call chain: (gdb) where #0 0x000003ffabc3192a in __strnlen_c_1 () from /lib64/libc.so.6 #1 0x000003ffabc293de in strcasestr () from /lib64/libc.so.6 #2 0x0000000001102ba2 in match_metric(list=0x1e6ea20 "inst_retired.any", n=<optimized out>) at util/metricgroup.c:368 #3 find_metric (map=<optimized out>, map=<optimized out>, metric=0x1e6ea20 "inst_retired.any") at util/metricgroup.c:765 #4 __resolve_metric (ids=0x0, map=<optimized out>, metric_list=0x0, metric_no_group=<optimized out>, m=<optimized out>) at util/metricgroup.c:844 #5 resolve_metric (ids=0x0, map=0x0, metric_list=0x0, metric_no_group=<optimized out>) at util/metricgroup.c:881 #6 metricgroup__add_metric (metric=<optimized out>, metric_no_group=metric_no_group@entry=false, events=<optimized out>, events@entry=0x3ffd84fb878, metric_list=0x0, metric_list@entry=0x3ffd84fb868, map=0x0) at util/metricgroup.c:943 #7 0x00000000011034ae in metricgroup__add_metric_list (map=0x13f9828 <map>, metric_list=0x3ffd84fb868, events=0x3ffd84fb878, metric_no_group=<optimized out>, list=<optimized out>) at util/metricgroup.c:988 #8 parse_groups (perf_evlist=perf_evlist@entry=0x1e70260, str=str@entry=0x12f34b2 "IPC", metric_no_group=<optimized out>, metric_no_merge=<optimized out>, fake_pmu=fake_pmu@entry=0x1462f18 <perf_pmu.fake>, metric_events=0x3ffd84fba58, map=0x1) at util/metricgroup.c:1040 #9 0x0000000001103eb2 in metricgroup__parse_groups_test( evlist=evlist@entry=0x1e70260, map=map@entry=0x13f9828 <map>, str=str@entry=0x12f34b2 "IPC", metric_no_group=metric_no_group@entry=false, metric_no_merge=metric_no_merge@entry=false, metric_events=0x3ffd84fba58) at util/metricgroup.c:1082 #10 0x00000000010c84d8 in __compute_metric (ratio2=0x0, name2=0x0, ratio1=<synthetic pointer>, name1=0x12f34b2 "IPC", vals=0x3ffd84fbad8, name=0x12f34b2 "IPC") at tests/parse-metric.c:159 #11 compute_metric (ratio=<synthetic pointer>, vals=0x3ffd84fbad8, name=0x12f34b2 "IPC") at tests/parse-metric.c:189 #12 test_ipc () at tests/parse-metric.c:208 ..... ..... omitted many more lines This test case was added with commit 218ca91df477 ("perf tests: Add parse metric test for frontend metric"). When I compile with make DEBUG=y it works fine and I do not get a core dump. It turned out that the above listed function call chain worked on a struct pmu_event array which requires a trailing element with zeroes which was missing. The marco map_for_each_event() loops over that array tests for members metric_expr/metric_name/metric_group being non-NULL. Adding this element fixes the issue. Output after: [root@t35lp46 perf]# ./perf test 67 67: Parse and process metrics : Ok [root@t35lp46 perf]# Signed-off-by: Thomas Richter <tmri...@linux.ibm.com> Reviewed-by: Sumanth Korikkar <suman...@linux.ibm.com> --- tools/perf/tests/parse-metric.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/perf/tests/parse-metric.c b/tools/perf/tests/parse-metric.c index fc0838a7abc2..80c71a10999d 100644 --- a/tools/perf/tests/parse-metric.c +++ b/tools/perf/tests/parse-metric.c @@ -70,6 +70,11 @@ static struct pmu_event pme_test[] = { { .metric_expr = "1/m3", .metric_name = "M3", +}, +{ + .metric_expr = NULL, + .metric_name = NULL, + .metric_group = NULL } }; -- 2.26.2