perf tools: Fix parse_events_error dereferences

Parse errors can be reported in struct parse_events_error but the
pointer passed is optional and can be NULL.  Ensure it is not NULL
before dereferencing it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Link: http://lkml.kernel.org/r/1432040746-1755-4-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 78032d887c1a..2a4d1ec02846 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1659,6 +1659,8 @@ void parse_events_evlist_error(struct parse_events_evlist *data,
 {
         struct parse_events_error *err = data->error;
 
+        if (!err)
+                return;
         err->idx = idx;
         err->str = strdup(str);
         WARN_ONCE(!err->str, "WARNING: failed to allocate error string");