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perf pmu: Add proper error handling to print_pmu_events()

tip:perf/core tip-bot for Arnaldo Carvalho de Melo 1 participant 1 message Oct 30, 2014 perf events

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Commit-ID:  7e4772dc99a3ebfc53708eff262f7a8155485e85
Gitweb:     http://git.kernel.org/tip/7e4772dc99a3ebfc53708eff262f7a8155485e85
Author:     Arnaldo Carvalho de Melo <[email protected]>
AuthorDate: Fri, 24 Oct 2014 10:25:09 -0300
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Wed, 29 Oct 2014 10:32:48 -0200

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 <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc David Ahern <[email protected]>
Cc Don Zickus <[email protected]>
Cc Frederic Weisbecker <[email protected]>
Cc Jean Pihet <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc Mike Galbraith <[email protected]>
Cc Namhyung Kim <[email protected]>
Cc Paul Mackerras <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Stephane Eranian <[email protected]>
Link http://lkml.kernel.org/n/[email protected] open here
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
---
 tools/perf/util/pmu.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)
tools/perf/util/pmu.c +22 -10
index 91dca60..881b754 100644
@@ -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)