When executing perf stat with armv8_pmu events with a workload, it will
report a segfault as result.
(gdb) bt
#0 0x0000000000603fc8 in perf_evsel__close_fd_cpu (evsel=<optimized out>,
cpu=<optimized out>) at evsel.c:122
#1 perf_evsel__close_cpu (evsel=evsel@entry=0x716e950, cpu=7) at evsel.c:156
#2 0x00000000004d4718 in evlist__close (evlist=0x70a7cb0) at util/evlist.c:1242
#3 0x0000000000453404 in __run_perf_stat (argc=3, argc@entry=1, argv=0x30,
argv@entry=0xfffffaea2f90, run_idx=119, run_idx@entry=1701998435)
at builtin-stat.c:929
#4 0x0000000000455058 in run_perf_stat (run_idx=1701998435,
argv=0xfffffaea2f90,
argc=1) at builtin-stat.c:947
#5 cmd_stat (argc=1, argv=0xfffffaea2f90) at builtin-stat.c:2357
#6 0x00000000004bb888 in run_builtin (p=p@entry=0x9764b8 <commands+288>,
argc=argc@entry=4, argv=argv@entry=0xfffffaea2f90) at perf.c:312
#7 0x00000000004bbb54 in handle_internal_command (argc=argc@entry=4,
argv=argv@entry=0xfffffaea2f90) at perf.c:364
#8 0x0000000000435378 in run_argv (argcp=<synthetic pointer>,
argv=<synthetic pointer>) at perf.c:408
#9 main (argc=4, argv=0xfffffaea2f90) at perf.c:538
After debugging, i found the root reason is that the xyarray fd is created
by evsel__open_per_thread() ignoring the cpu passed in
create_perf_stat_counter(), while the evsel' cpumap is assigned as the
corresponding PMU's cpumap in __add_event(). Thus, the xyarray fd is created
with ncpus of dummy cpumap and an out of bounds 'cpu' index will be used in
perf_evsel__close_fd_cpu().
To address this, add a flag to mark this situation and avoid using the
affinity technique when closing/enabling/disabling events.
Fixes: 7736627b865d ("perf stat: Use affinity for closing file descriptors")
Fixes: 704e2f5b700d ("perf stat: Use affinity for enabling/disabling events")
Signed-off-by: Wei Li <liwei...@huawei.com>
---
tools/lib/perf/include/internal/evlist.h | 1 +
tools/perf/builtin-stat.c | 3 +++
tools/perf/util/evlist.c | 23 ++++++++++++++++++++++-
3 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/tools/lib/perf/include/internal/evlist.h
b/tools/lib/perf/include/internal/evlist.h
index 2d0fa02b036f..c02d7e583846 100644
--- a/tools/lib/perf/include/internal/evlist.h
+++ b/tools/lib/perf/include/internal/evlist.h
@@ -17,6 +17,7 @@ struct perf_evlist {
struct list_head entries;
int nr_entries;
bool has_user_cpus;
+ bool open_per_thread;
struct perf_cpu_map *cpus;
struct perf_cpu_map *all_cpus;
struct perf_thread_map *threads;
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index fddc97cac984..6e6ceacce634 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -725,6 +725,9 @@ static int __run_perf_stat(int argc, const char **argv, int
run_idx)
if (group)
perf_evlist__set_leader(evsel_list);
+ if (!(target__has_cpu(&target) && !target__has_per_thread(&target)))
+ evsel_list->core.open_per_thread = true;
+
if (affinity__setup(&affinity) < 0)
return -1;
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index e3fa3bf7498a..bf8a3ccc599f 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -383,6 +383,15 @@ void evlist__disable(struct evlist *evlist)
int cpu, i, imm = 0;
bool has_imm = false;
+ if (evlist->core.open_per_thread) {
+ evlist__for_each_entry(evlist, pos) {
+ if (pos->disabled || !evsel__is_group_leader(pos) ||
!pos->core.fd)
+ continue;
+ evsel__disable(pos);
+ }
+ goto out;
+ }
+
if (affinity__setup(&affinity) < 0)
return;
@@ -414,6 +423,7 @@ void evlist__disable(struct evlist *evlist)
pos->disabled = true;
}
+out:
evlist->enabled = false;
}
@@ -423,6 +433,15 @@ void evlist__enable(struct evlist *evlist)
struct affinity affinity;
int cpu, i;
+ if (evlist->core.open_per_thread) {
+ evlist__for_each_entry(evlist, pos) {
+ if (!evsel__is_group_leader(pos) || !pos->core.fd)
+ continue;
+ evsel__enable(pos);
+ }
+ goto out;
+ }
+
if (affinity__setup(&affinity) < 0)
return;
@@ -444,6 +463,7 @@ void evlist__enable(struct evlist *evlist)
pos->disabled = false;
}
+out:
evlist->enabled = true;
}
@@ -1223,9 +1243,10 @@ void evlist__close(struct evlist *evlist)
/*
* With perf record core.cpus is usually NULL.
+ * Or perf stat may open events per-thread.
* Use the old method to handle this for now.
*/
- if (!evlist->core.cpus) {
+ if (evlist->core.open_per_thread || !evlist->core.cpus) {
evlist__for_each_entry_reverse(evlist, evsel)
evsel__close(evsel);
return;
--
2.17.1
