diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index fcfbef07b92d8c9fbbce2adb35c4e43428818c30..d281ae2b54e8fef7b85574a8b799dc33c21e9e44 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -213,7 +213,7 @@ static int convert_exec_to_group(const char *exec, char **result)
 		goto out;
 	}
 
-	for (ptr2 = ptr1; ptr2 != '\0'; ptr2++) {
+	for (ptr2 = ptr1; *ptr2 != '\0'; ptr2++) {
 		if (!isalnum(*ptr2) && *ptr2 != '_') {
 			*ptr2 = '\0';
 			break;