perf diff: Add missing hists__init() call at tool start

It also uses hists/hist_entries, hists__init() should be called before
creating any evsels.

Otherwise no extra space will be allocated per perf_evsel nor this space
will be initialized when allocating a new perf_evsel instance, resulting
in reads/writes to non allocated space, oops. Fix it.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Link: http://lkml.kernel.org/r/1414004561-22096-1-git-send-email-kan.liang@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 8c5c11ca8c539d5292d9ceb3524754e4e06ead49..25114c9a6801d65d822e6f6e082e6e70b1144aab 100644 (file)
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -1142,6 +1142,11 @@ static int data_init(int argc, const char **argv)
 
 int cmd_diff(int argc, const char **argv, const char *prefix __maybe_unused)
 {
+       int ret = hists__init();
+
+       if (ret < 0)
+               return ret;
+
        perf_config(perf_default_config, NULL);
 
        argc = parse_options(argc, argv, options, diff_usage, 0);