> From: Wangnan (F) [mailto:[email protected]] > > Sorry, forget to CC kernel mailing list... > > On 2015/9/2 14:49, Wang Nan wrote: > > If parse_events__scanner() collects no entry, perf_evlist__last(evlist) > > is invalid. > > > > Although it shouldn't happen at this point, before calling > > perf_evlist__last(), we should ensure the list is not empty for safety > > reason. > > > > There are 3 places need this checking: > > > > 1. Before setting cmdline_group_boundary; > > 2. Before __perf_evlist__set_leader(); > > 3. In foreach_evsel_in_last_glob. > >
This looks OK to me. Reviewed-by: Masami Hiramatsu <[email protected]> Thanks! > > Signed-off-by: Wang Nan <[email protected]> > > Cc: Arnaldo Carvalho de Melo <[email protected]> > > Cc: Alexei Starovoitov <[email protected]> > > Cc: Jiri Olsa <[email protected]> > > Cc: Masami Hiramatsu <[email protected]> > > Cc: Namhyung Kim <[email protected]> > > Cc: Zefan Li <[email protected]> > > Cc: [email protected] > > --- > > > > Merge all 3 list_empty() test together into one patch. > > > > Add warning messages. > > > > Improve commit message. > > > > --- > > tools/perf/util/parse-events.c | 22 +++++++++++++++++++--- > > 1 file changed, 19 insertions(+), 3 deletions(-) > > > > diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c > > index d826e6f..069848d 100644 > > --- a/tools/perf/util/parse-events.c > > +++ b/tools/perf/util/parse-events.c > > @@ -793,6 +793,11 @@ void parse_events__set_leader(char *name, struct > > list_head *list) > > { > > struct perf_evsel *leader; > > > > + if (list_empty(list)) { > > + __WARN_printf("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; > > @@ -1143,10 +1148,15 @@ int parse_events(struct perf_evlist *evlist, const > > char *str, > > int entries = data.idx - evlist->nr_entries; > > struct perf_evsel *last; > > > > + if (!list_empty(&data.list)) { > > + last = list_entry(data.list.prev, > > + struct perf_evsel, node); > > + last->cmdline_group_boundary = true; > > + } else > > + __WARN_printf("WARNING: event parser found nothing"); > > + > > perf_evlist__splice_list_tail(evlist, &data.list, entries); > > evlist->nr_groups += data.nr_groups; > > - last = perf_evlist__last(evlist); > > - last->cmdline_group_boundary = true; > > > > return 0; > > } > > @@ -1252,7 +1262,13 @@ foreach_evsel_in_last_glob(struct perf_evlist > > *evlist, > > struct perf_evsel *last = NULL; > > int err; > > > > - if (evlist->nr_entries > 0) > > + /* > > + * 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 (!list_empty(&evlist->entries)) > > last = perf_evlist__last(evlist); > > > > do { >
