Index: lib/sanitizer_common/sanitizer_printf.cc
===================================================================
--- lib/sanitizer_common/sanitizer_printf.cc
+++ lib/sanitizer_common/sanitizer_printf.cc
@@ -277,7 +277,8 @@
     break;
 #   undef CHECK_NEEDED_LENGTH
   }
-  RawWrite(buffer);
+  if (!PrintfAndReportCallback)
+    RawWrite(buffer);
   if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
     WriteToSyslog(buffer);
   CallPrintfAndReportCallback(buffer);