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>

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 91dca604c422779533510778b30a2e46fb9c5437..881b75490533f9e77b77d4168b8c940fcb56a800 100644 (file)
--- 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)