diff --git a/include/mangle.h b/include/mangle.h
index 0a4b60c1c..08c66cb47 100644
--- a/include/mangle.h
+++ b/include/mangle.h
@@ -14,12 +14,14 @@ extern char *unmangle(const char *s, const char **end);
 
 static inline void unmangle_string(char *s)
 {
-	unmangle_to_buffer(s, s, strlen(s) + 1);
+	if (s)
+		unmangle_to_buffer(s, s, strlen(s) + 1);
 }
 
 static inline void unhexmangle_string(char *s)
 {
-	unhexmangle_to_buffer(s, s, strlen(s) + 1);
+	if (s)
+		unhexmangle_to_buffer(s, s, strlen(s) + 1);
 }
 
 #endif /* UTIL_LINUX_MANGLE_H */