From: Wang Nan <wangn...@huawei.com> Don't blindly retrieve and use a last element in the lists returned by parse_events__scanner(), as it may have collected no entries, i.e. return an empty list.
Signed-off-by: Wang Nan <wangn...@huawei.com> Cc: Alexei Starovoitov <a...@plumgrid.com> Cc: Brendan Gregg <brendan.d.gr...@gmail.com> Cc: Daniel Borkmann <dan...@iogearbox.net> Cc: David Ahern <dsah...@gmail.com> Cc: He Kuang <heku...@huawei.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Kaixu Xia <xiaka...@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Zefan Li <lize...@huawei.com> Cc: pi3or...@163.com Link: http://lkml.kernel.org/r/1441523623-152703-2-git-send-email-wangn...@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/parse-events.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 0fde5293a38e..61c2bc20926d 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -827,6 +827,11 @@ void parse_events__set_leader(char *name, struct list_head *list) { struct perf_evsel *leader; + if (list_empty(list)) { + WARN_ONCE(true, "WARNING: failed to set leader: empty list"); + return; + } + __perf_evlist__set_leader(list); leader = list_entry(list->next, struct perf_evsel, node); leader->group_name = name ? strdup(name) : NULL; @@ -1176,6 +1181,11 @@ int parse_events(struct perf_evlist *evlist, const char *str, if (!ret) { struct perf_evsel *last; + if (list_empty(&data.list)) { + WARN_ONCE(true, "WARNING: event parser found nothing"); + return -1; + } + perf_evlist__splice_list_tail(evlist, &data.list); evlist->nr_groups += data.nr_groups; last = perf_evlist__last(evlist); @@ -1285,6 +1295,12 @@ foreach_evsel_in_last_glob(struct perf_evlist *evlist, struct perf_evsel *last = NULL; int err; + /* + * Don't return when list_empty, give func a chance to report + * error when it found last == NULL. + * + * So no need to WARN here, let *func do this. + */ if (evlist->nr_entries > 0) last = perf_evlist__last(evlist); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
