Index: lib/libc/stdio/fread.c
===================================================================
RCS file: /cvsroot/src/lib/libc/stdio/fread.c,v
retrieving revision 1.22
diff -u -r1.22 fread.c
--- lib/libc/stdio/fread.c	15 Mar 2012 18:22:30 -0000	1.22
+++ lib/libc/stdio/fread.c	22 Feb 2020 21:27:11 -0000
@@ -68,16 +68,21 @@
 	_DIAGASSERT(buf != NULL);
 
 	FLOCKFILE(fp);
-	if (fp->_r < 0)
-		fp->_r = 0;
 	total = resid;
 	p = buf;
+
+	if (fp->_r <= 0) {
+		/* Nothing to read on enter, refill the buffers. */
+		goto refill;
+	}
+
 	while (resid > (size_t)(r = fp->_r)) {
 		(void)memcpy(p, fp->_p, (size_t)r);
 		fp->_p += r;
 		/* fp->_r = 0 ... done in __srefill */
 		p += r;
 		resid -= r;
+refill:
 		if (__srefill(fp)) {
 			/* no more input: return partial result */
 			FUNLOCKFILE(fp);