perf pmu: Add proper error handling to print_pmu_events()

It was silently returning or printing "(null)" when no memory was
available at various points. Fix it by checking and warning the user
when that happens.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-835udmf66x9nza504cu6irz9@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 22 insertions, 10 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 91dca604c422..881b75490533 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -753,9 +753,9 @@ void print_pmu_events(const char *event_glob, bool name_only)
                 if (pmu->selectable)
                         len++;
         }
-        aliases = malloc(sizeof(char *) * len);
+        aliases = zalloc(sizeof(char *) * len);
         if (!aliases)
-                return;
+                goto out_enomem;
         pmu = NULL;
         j = 0;
         while ((pmu = perf_pmu__scan(pmu)) != NULL) {
@@ -768,16 +768,20 @@ void print_pmu_events(const char *event_glob, bool name_only)
                               (!is_cpu && strglobmatch(alias->name,
                                                        event_glob))))
                                 continue;
-                        aliases[j] = name;
+
                         if (is_cpu && !name_only)
-                                aliases[j] = format_alias_or(buf, sizeof(buf),
-                                                              pmu, alias);
-                        aliases[j] = strdup(aliases[j]);
+                                name = format_alias_or(buf, sizeof(buf), pmu, alias);
+
+                        aliases[j] = strdup(name);
+                        if (aliases[j] == NULL)
+                                goto out_enomem;
                         j++;
                 }
                 if (pmu->selectable) {
-                        scnprintf(buf, sizeof(buf), "%s//", pmu->name);
-                        aliases[j] = strdup(buf);
+                        char *s;
+                        if (asprintf(&s, "%s//", pmu->name) < 0)
+                                goto out_enomem;
+                        aliases[j] = s;
                         j++;
                 }
         }
@@ -789,12 +793,20 @@ void print_pmu_events(const char *event_glob, bool name_only)
                         continue;
                 }
                 printf("  %-50s [Kernel PMU event]\n", aliases[j]);
-                zfree(&aliases[j]);
                 printed++;
         }
         if (printed)
                 printf("\n");
-        free(aliases);
+out_free:
+        for (j = 0; j < len; j++)
+                zfree(&aliases[j]);
+        zfree(&aliases);
+        return;
+
+out_enomem:
+        printf("FATAL: not enough memory to print PMU events\n");
+        if (aliases)
+                goto out_free;
 }
 
 bool pmu_have_event(const char *pname, const char *name)