diff options
| author | Ian Rogers <irogers@google.com> | 2022-03-17 16:16:43 -0700 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2022-03-18 18:39:09 -0300 |
| commit | 8b464eac9765dfc84d0327fa3f3668faa439d1ce (patch) | |
| tree | 33b01cedf3690cd112774f742caa9bf470d3cd6f | |
| parent | 3cf6a32f3f2a45944dd5be5c6ac4deb46bcd3bee (diff) | |
perf evlist: Avoid iteration for empty evlist.
As seen with 'perf stat --null ..' and reported in:
https://lore.kernel.org/lkml/YjCLcpcX2peeQVCH@kernel.org/
v2. Avoids setting evsel in the empty list case as suggested by Jiri Olsa.
Committer testing:
Before:
$ perf stat --null sleep 1
Segmentation fault (core dumped)
$
After:
$ perf stat --null sleep 1
Performance counter stats for 'sleep 1':
1.010340646 seconds time elapsed
0.001420000 seconds user
0.000000000 seconds sys
$
Fixes: 472832d2c000b961 ("perf evlist: Refactor evlist__for_each_cpu()")
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220317231643.550902-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/evlist.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index eaad04e1672a..41a66a48cbdf 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -346,7 +346,7 @@ struct evlist_cpu_iterator evlist__cpu_begin(struct evlist *evlist, struct affin { struct evlist_cpu_iterator itr = { .container = evlist, - .evsel = evlist__first(evlist), + .evsel = NULL, .cpu_map_idx = 0, .evlist_cpu_map_idx = 0, .evlist_cpu_map_nr = perf_cpu_map__nr(evlist->core.all_cpus), @@ -354,16 +354,22 @@ struct evlist_cpu_iterator evlist__cpu_begin(struct evlist *evlist, struct affin .affinity = affinity, }; - if (itr.affinity) { - itr.cpu = perf_cpu_map__cpu(evlist->core.all_cpus, 0); - affinity__set(itr.affinity, itr.cpu.cpu); - itr.cpu_map_idx = perf_cpu_map__idx(itr.evsel->core.cpus, itr.cpu); - /* - * If this CPU isn't in the evsel's cpu map then advance through - * the list. - */ - if (itr.cpu_map_idx == -1) - evlist_cpu_iterator__next(&itr); + if (evlist__empty(evlist)) { + /* Ensure the empty list doesn't iterate. */ + itr.evlist_cpu_map_idx = itr.evlist_cpu_map_nr; + } else { + itr.evsel = evlist__first(evlist); + if (itr.affinity) { + itr.cpu = perf_cpu_map__cpu(evlist->core.all_cpus, 0); + affinity__set(itr.affinity, itr.cpu.cpu); + itr.cpu_map_idx = perf_cpu_map__idx(itr.evsel->core.cpus, itr.cpu); + /* + * If this CPU isn't in the evsel's cpu map then advance + * through the list. + */ + if (itr.cpu_map_idx == -1) + evlist_cpu_iterator__next(&itr); + } } return itr; } |