perf script perl: Do error checking on new backtrace routine

This ended up triggering these warnings when building on Ubuntu 12.04.5:

  util/scripting-engines/trace-event-perl.c: In function 'perl_process_callchain':
  util/scripting-engines/trace-event-perl.c:293:4: error: value computed is not used [-Werror=unused-value]
  util/scripting-engines/trace-event-perl.c:294:4: error: value computed is not used [-Werror=unused-value]
  util/scripting-engines/trace-event-perl.c:295:4: error: value computed is not used [-Werror=unused-value]
  util/scripting-engines/trace-event-perl.c:297:4: error: value computed is not used [-Werror=unused-value]
  util/scripting-engines/trace-event-perl.c:309:4: error: value computed is not used [-Werror=unused-value]
  cc1: all warnings being treated as errors
  mv: cannot stat `/tmp/build/perf/util/scripting-engines/.trace-event-perl.o.tmp': No such file or directory
  make[4]: *** [/tmp/build/perf/util/scripting-engines/trace-event-perl.o] Error 1

Fix it by doing error checking when building the perl data structures
related to callchains.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@gmail.com>
Fixes: f7380c12ec6c ("perf script perl: Perl scripts now get a backtrace, like the python ones")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 21 insertions, 9 deletions

diff --git a/tools/perf/util/scripting-engines/trace-event-perl.c b/tools/perf/util/scripting-engines/trace-event-perl.c
index 1d160855cda9..35ed00a600fb 100644
--- a/tools/perf/util/scripting-engines/trace-event-perl.c
+++ b/tools/perf/util/scripting-engines/trace-event-perl.c
@@ -283,18 +283,27 @@ static SV *perl_process_callchain(struct perf_sample *sample,
                 if (!elem)
                         goto exit;
 
-                hv_stores(elem, "ip", newSVuv(node->ip));
+                if (!hv_stores(elem, "ip", newSVuv(node->ip))) {
+                        hv_undef(elem);
+                        goto exit;
+                }
 
                 if (node->sym) {
                         HV *sym = newHV();
-                        if (!sym)
+                        if (!sym) {
+                                hv_undef(elem);
+                                goto exit;
+                        }
+                        if (!hv_stores(sym, "start",   newSVuv(node->sym->start)) ||
+                            !hv_stores(sym, "end",     newSVuv(node->sym->end)) ||
+                            !hv_stores(sym, "binding", newSVuv(node->sym->binding)) ||
+                            !hv_stores(sym, "name",    newSVpvn(node->sym->name,
+                                                                node->sym->namelen)) ||
+                            !hv_stores(elem, "sym",    newRV_noinc((SV*)sym))) {
+                                hv_undef(sym);
+                                hv_undef(elem);
                                 goto exit;
-                        hv_stores(sym, "start",   newSVuv(node->sym->start));
-                        hv_stores(sym, "end",     newSVuv(node->sym->end));
-                        hv_stores(sym, "binding", newSVuv(node->sym->binding));
-                        hv_stores(sym, "name",    newSVpvn(node->sym->name,
-                                                           node->sym->namelen));
-                        hv_stores(elem, "sym",    newRV_noinc((SV*)sym));
+                        }
                 }
 
                 if (node->map) {
@@ -306,7 +315,10 @@ static SV *perl_process_callchain(struct perf_sample *sample,
                                 else if (map->dso->name)
                                         dsoname = map->dso->name;
                         }
-                        hv_stores(elem, "dso", newSVpv(dsoname,0));
+                        if (!hv_stores(elem, "dso", newSVpv(dsoname,0))) {
+                                hv_undef(elem);
+                                goto exit;
+                        }
                 }
 
                 callchain_cursor_advance(&callchain_cursor);