===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/ssh.c,v
retrieving revision 1.437
retrieving revision 1.438
diff -u -r1.437 -r1.438
--- src/usr.bin/ssh/ssh.c	2016/03/07 19:02:43	1.437
+++ src/usr.bin/ssh/ssh.c	2016/04/29 08:07:53	1.438
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.437 2016/03/07 19:02:43 djm Exp $ */
+/* $OpenBSD: ssh.c,v 1.438 2016/04/29 08:07:53 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1346,7 +1346,7 @@
 control_persist_detach(void)
 {
 	pid_t pid;
-	int devnull;
+	int devnull, keep_stderr;
 
 	debug("%s: backgrounding master process", __func__);
 
@@ -1377,8 +1377,10 @@
 		error("%s: open(\"/dev/null\"): %s", __func__,
 		    strerror(errno));
 	} else {
+		keep_stderr = log_is_on_stderr() && debug_flag;
 		if (dup2(devnull, STDIN_FILENO) == -1 ||
-		    dup2(devnull, STDOUT_FILENO) == -1)
+		    dup2(devnull, STDOUT_FILENO) == -1 ||
+		    (!keep_stderr && dup2(devnull, STDERR_FILENO) == -1))
 			error("%s: dup2: %s", __func__, strerror(errno));
 		if (devnull > STDERR_FILENO)
 			close(devnull);