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e47749f179
Running commands such as
# ./perf stat -e cs -- true
Segmentation fault (core dumped)
# ./perf stat -e cpu-clock-- true
Segmentation fault (core dumped)
#
dump core. This should not happen as these events are defined
even when no hardware PMU is available.
Debugging this reveals this call chain:
perf_pmus__find_by_type(type=1)
+--> pmu_read_sysfs(core_only=false)
+--> perf_pmu__find2(dirfd=3, name=0x152a113 "software")
+--> perf_pmu__lookup(pmus=0x14f0568 <other_pmus>, dirfd=3,
lookup_name=0x152a113 "software")
+--> perf_pmu__find_events_table (pmu=0x1532130)
Now the pmu is "software" and it tries to find a proper table
generated by the pmu-event generation process for s390:
# cd pmu-events/
# ./jevents.py s390 all /root/linux/tools/perf/pmu-events/arch |\
grep -E '^const struct pmu_table_entry'
const struct pmu_table_entry pmu_events__cf_z10[] = {
const struct pmu_table_entry pmu_events__cf_z13[] = {
const struct pmu_table_entry pmu_metrics__cf_z13[] = {
const struct pmu_table_entry pmu_events__cf_z14[] = {
const struct pmu_table_entry pmu_metrics__cf_z14[] = {
const struct pmu_table_entry pmu_events__cf_z15[] = {
const struct pmu_table_entry pmu_metrics__cf_z15[] = {
const struct pmu_table_entry pmu_events__cf_z16[] = {
const struct pmu_table_entry pmu_metrics__cf_z16[] = {
const struct pmu_table_entry pmu_events__cf_z196[] = {
const struct pmu_table_entry pmu_events__cf_zec12[] = {
const struct pmu_table_entry pmu_metrics__cf_zec12[] = {
const struct pmu_table_entry pmu_events__test_soc_cpu[] = {
const struct pmu_table_entry pmu_metrics__test_soc_cpu[] = {
const struct pmu_table_entry pmu_events__test_soc_sys[] = {
#
However event "software" is not listed, as can be seen in the
generated const struct pmu_events_map pmu_events_map[].
So in function perf_pmu__find_events_table(), the variable
table is initialized to NULL, but never set to a proper
value. The function scans all generated &pmu_events_map[]
tables, but no table matches, because the tables are
s390 CPU Measurement unit specific:
i = 0;
for (;;) {
const struct pmu_events_map *map = &pmu_events_map[i++];
if (!map->arch)
break;
--> the maps are there because the build generated them
if (!strcmp_cpuid_str(map->cpuid, cpuid)) {
table = &map->event_table;
break;
}
--> Since no matching CPU string the table var remains 0x0
}
free(cpuid);
if (!pmu)
return table;
--> The pmu is "software" so it exists and no return
--> and here perf dies because table is 0x0
for (i = 0; i < table->num_pmus; i++) {
...
}
return NULL;
Fix this and do not access the table variable. Instead return 0x0
which is the same return code when the for-loop was not successful.
Output after:
# ./perf stat -e cs -- true
Performance counter stats for 'true':
0 cs
0.000853105 seconds time elapsed
0.000061000 seconds user
0.000827000 seconds sys
# ./perf stat -e cpu-clock -- true
Performance counter stats for 'true':
0.25 msec cpu-clock # 0.341 CPUs utilized
0.000728383 seconds time elapsed
0.000055000 seconds user
0.000706000 seconds sys
# ./perf stat -e cycles -- true
Performance counter stats for 'true':
<not supported> cycles
0.000767298 seconds time elapsed
0.000055000 seconds user
0.000739000 seconds sys
#
Fixes:
|
||
|---|---|---|
| .. | ||
| arch | ||
| bench | ||
| dlfilters | ||
| Documentation | ||
| include/perf | ||
| jvmti | ||
| pmu-events | ||
| python | ||
| scripts | ||
| tests | ||
| trace | ||
| ui | ||
| util | ||
| .gitignore | ||
| Build | ||
| builtin-annotate.c | ||
| builtin-bench.c | ||
| builtin-buildid-cache.c | ||
| builtin-buildid-list.c | ||
| builtin-c2c.c | ||
| builtin-config.c | ||
| builtin-daemon.c | ||
| builtin-data.c | ||
| builtin-diff.c | ||
| builtin-evlist.c | ||
| builtin-ftrace.c | ||
| builtin-help.c | ||
| builtin-inject.c | ||
| builtin-kallsyms.c | ||
| builtin-kmem.c | ||
| builtin-kvm.c | ||
| builtin-kwork.c | ||
| builtin-list.c | ||
| builtin-lock.c | ||
| builtin-mem.c | ||
| builtin-probe.c | ||
| builtin-record.c | ||
| builtin-report.c | ||
| builtin-sched.c | ||
| builtin-script.c | ||
| builtin-stat.c | ||
| builtin-timechart.c | ||
| builtin-top.c | ||
| builtin-trace.c | ||
| builtin-version.c | ||
| builtin.h | ||
| check-headers.sh | ||
| command-list.txt | ||
| CREDITS | ||
| design.txt | ||
| Makefile | ||
| Makefile.config | ||
| Makefile.perf | ||
| MANIFEST | ||
| perf-archive.sh | ||
| perf-completion.sh | ||
| perf-iostat.sh | ||
| perf-read-vdso.c | ||
| perf-sys.h | ||
| perf.c | ||
| perf.h | ||