diff --git a/compiler-rt/lib/msan/msan_interceptors.cpp b/compiler-rt/lib/msan/msan_interceptors.cpp
--- a/compiler-rt/lib/msan/msan_interceptors.cpp
+++ b/compiler-rt/lib/msan/msan_interceptors.cpp
@@ -481,7 +481,7 @@
   ENSURE_MSAN_INITED();
   va_list ap;
   va_start(ap, format);
-  int res = vswprintf(str, size, format, ap);
+  int res = REAL(vswprintf)(str, size, format, ap);
   va_end(ap);
   return res;
 }