3 files changed, 27 insertions, 3 deletions
diff --git a/newlib/libc/include/sys/config.h b/newlib/libc/include/sys/config.h
index 58305d4a8..0ac2b4ec8 100644
--- a/newlib/libc/include/sys/config.h
+++ b/newlib/libc/include/sys/config.h
@@ -202,4 +202,12 @@
 #endif
 #endif
 
+/* See if small reent asked for at configuration time and
+   is not chosen by the platform by default.  */
+#ifdef _WANT_REENT_SMALL
+#ifndef _REENT_SMALL
+#define _REENT_SMALL
+#endif
+#endif
+
 #endif /* __SYS_CONFIG_H__ */
diff --git a/newlib/libc/stdio/fflush.c b/newlib/libc/stdio/fflush.c
index a8ef755c2..d46b41f94 100644
--- a/newlib/libc/stdio/fflush.c
+++ b/newlib/libc/stdio/fflush.c
@@ -67,6 +67,22 @@ _DEFUN(fflush, (fp),
   if (fp == NULL)
     return _fwalk (_GLOBAL_REENT, fflush);
 
+#ifdef _REENT_SMALL
+  /* For REENT_SMALL platforms, it is possible we are being
+     called for the first time on a std stream.  This std
+     stream can belong to a reentrant struct that is not
+     _REENT.  If CHECK_INIT gets called below based on _REENT,
+     we will end up changing said file pointers to the equivalent
+     std stream off of _REENT.  This causes unexpected behavior if
+     there is any data to flush on the _REENT std stream.  There
+     are two alternatives to fix this:  1) make a reentrant fflush
+     or 2) simply recognize that this file has nothing to flush
+     and return immediately before performing a CHECK_INIT.  Choice
+     2 is implemented here due to its simplicity.  */
+  if (fp->_bf._base == NULL)
+    return 0;
+#endif /* _REENT_SMALL  */
+
   CHECK_INIT (_REENT, fp);
 
   _flockfile (fp);
diff --git a/newlib/libc/stdio/local.h b/newlib/libc/stdio/local.h
index 704b6be03..4263a9de6 100644
--- a/newlib/libc/stdio/local.h
+++ b/newlib/libc/stdio/local.h
@@ -55,11 +55,11 @@ struct _glue * _EXFUN(__sfmoreglue,(struct _reent *,int n));
       if ((ptr) && !(ptr)->__sdidinit)		\
 	__sinit (ptr);				\
       if ((fp) == (FILE *)&__sf_fake_stdin)	\
-	(fp) = stdin;				\
+	(fp) = _stdin_r(ptr);			\
       else if ((fp) == (FILE *)&__sf_fake_stdout) \
-	(fp) = stdout;				\
+	(fp) = _stdout_r(ptr);			\
       else if ((fp) == (FILE *)&__sf_fake_stderr) \
-	(fp) = stderr;				\
+	(fp) = _stderr_r(ptr);			\
     }						\
   while (0)
 #else /* !_REENT_SMALL   */