diff --git a/lib/libc/stdio/fvwrite.c b/lib/libc/stdio/fvwrite.c
index 50b32b8eca6e..2a161859afa9 100644
--- a/lib/libc/stdio/fvwrite.c
+++ b/lib/libc/stdio/fvwrite.c
@@ -1,207 +1,216 @@
 /*-
  * SPDX-License-Identifier: BSD-3-Clause
  *
  * Copyright (c) 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
 static char sccsid[] = "@(#)fvwrite.c	8.1 (Berkeley) 6/4/93";
 #endif /* LIBC_SCCS and not lint */
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "local.h"
 #include "fvwrite.h"
 
 /*
  * Write some memory regions.  Return zero on success, EOF on error.
  *
  * This routine is large and unsightly, but most of the ugliness due
  * to the three different kinds of output buffering is handled here.
  */
 int
 __sfvwrite(FILE *fp, struct __suio *uio)
 {
 	size_t len;
+	unsigned char *old_p;
 	char *p;
 	struct __siov *iov;
 	int w, s;
 	char *nl;
 	int nlknown, nldist;
 
 	if (uio->uio_resid == 0)
 		return (0);
 	/* make sure we can write */
 	if (prepwrite(fp) != 0)
 		return (EOF);
 
 #define	MIN(a, b) ((a) < (b) ? (a) : (b))
 #define	COPY(n)	  (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
 
 	iov = uio->uio_iov;
 	p = iov->iov_base;
 	len = iov->iov_len;
 	iov++;
 #define GETIOV(extra_work) \
 	while (len == 0) { \
 		extra_work; \
 		p = iov->iov_base; \
 		len = iov->iov_len; \
 		iov++; \
 	}
 	if (fp->_flags & __SNBF) {
 		/*
 		 * Unbuffered: write up to BUFSIZ bytes at a time.
 		 */
 		do {
 			GETIOV(;);
 			w = _swrite(fp, p, MIN(len, BUFSIZ));
 			if (w <= 0)
 				goto err;
 			p += w;
 			len -= w;
 		} while ((uio->uio_resid -= w) != 0);
 	} else if ((fp->_flags & __SLBF) == 0) {
 		/*
 		 * Fully buffered: fill partially full buffer, if any,
 		 * and then flush.  If there is no partial buffer, write
 		 * one _bf._size byte chunk directly (without copying).
 		 *
 		 * String output is a special case: write as many bytes
 		 * as fit, but pretend we wrote everything.  This makes
 		 * snprintf() return the number of bytes needed, rather
 		 * than the number used, and avoids its write function
 		 * (so that the write function can be invalid).
 		 */
 		do {
 			GETIOV(;);
 			if ((fp->_flags & (__SALC | __SSTR)) ==
 			    (__SALC | __SSTR) && fp->_w < len) {
 				size_t blen = fp->_p - fp->_bf._base;
 
 				/*
 				 * Alloc an extra 128 bytes (+ 1 for NULL)
 				 * so we don't call realloc(3) so often.
 				 */
 				fp->_w = len + 128;
 				fp->_bf._size = blen + len + 128;
 				fp->_bf._base =
 				    reallocf(fp->_bf._base, fp->_bf._size + 1);
 				if (fp->_bf._base == NULL)
 					goto err;
 				fp->_p = fp->_bf._base + blen;
 			}
 			w = fp->_w;
 			if (fp->_flags & __SSTR) {
 				if (len < w)
 					w = len;
 				if (w > 0) {
 					COPY(w);        /* copy MIN(fp->_w,len), */
 					fp->_w -= w;
 					fp->_p += w;
 				}
 				w = len;	/* but pretend copied all */
 			} else if (fp->_p > fp->_bf._base && len > w) {
 				/* fill and flush */
 				COPY(w);
 				/* fp->_w -= w; */ /* unneeded */
 				fp->_p += w;
-				if (__fflush(fp))
+				old_p = fp->_p;
+				if (__fflush(fp) == EOF) {
+					if (old_p == fp->_p)
+						fp->_p -= w;
 					goto err;
+				}
 			} else if (len >= (w = fp->_bf._size)) {
 				/* write directly */
 				w = _swrite(fp, p, w);
 				if (w <= 0)
 					goto err;
 			} else {
 				/* fill and done */
 				w = len;
 				COPY(w);
 				fp->_w -= w;
 				fp->_p += w;
 			}
 			p += w;
 			len -= w;
 		} while ((uio->uio_resid -= w) != 0);
 	} else {
 		/*
 		 * Line buffered: like fully buffered, but we
 		 * must check for newlines.  Compute the distance
 		 * to the first newline (including the newline),
 		 * or `infinity' if there is none, then pretend
 		 * that the amount to write is MIN(len,nldist).
 		 */
 		nlknown = 0;
 		nldist = 0;	/* XXX just to keep gcc happy */
 		do {
 			GETIOV(nlknown = 0);
 			if (!nlknown) {
 				nl = memchr((void *)p, '\n', len);
 				nldist = nl ? nl + 1 - p : len + 1;
 				nlknown = 1;
 			}
 			s = MIN(len, nldist);
 			w = fp->_w + fp->_bf._size;
 			if (fp->_p > fp->_bf._base && s > w) {
 				COPY(w);
 				/* fp->_w -= w; */
 				fp->_p += w;
-				if (__fflush(fp))
+				old_p = fp->_p;
+				if (__fflush(fp) == EOF) {
+					if (old_p == fp->_p)
+						fp->_p -= w;
 					goto err;
+				}
 			} else if (s >= (w = fp->_bf._size)) {
 				w = _swrite(fp, p, w);
 				if (w <= 0)
 				 	goto err;
 			} else {
 				w = s;
 				COPY(w);
 				fp->_w -= w;
 				fp->_p += w;
 			}
 			if ((nldist -= w) == 0) {
 				/* copied the newline: flush and forget */
 				if (__fflush(fp))
 					goto err;
 				nlknown = 0;
 			}
 			p += w;
 			len -= w;
 		} while ((uio->uio_resid -= w) != 0);
 	}
 	return (0);
 
 err:
 	fp->_flags |= __SERR;
 	return (EOF);
 }