diff --git a/ChangeLog b/ChangeLog
index 03bba82de7..c2d99a027b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2014-12-10  Andreas Schwab  <schwab@suse.de>
+
+	[BZ #12847]
+	* sysdeps/nptl/fork.c (fresetlockfiles): Skip files with
+	user-controlled locks.
+
 2014-12-10  Richard Earnshaw  <rearnsha@arm.com>
 
 	* sysdeps/aarch64/strchrnul.S (vrepmask): Use a call-clobbered
diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c
index a7dafa82ab..7ef693d529 100644
--- a/sysdeps/nptl/fork.c
+++ b/sysdeps/nptl/fork.c
@@ -46,7 +46,8 @@ fresetlockfiles (void)
   _IO_ITER i;
 
   for (i = _IO_iter_begin(); i != _IO_iter_end(); i = _IO_iter_next(i))
-    _IO_lock_init (*((_IO_lock_t *) _IO_iter_file(i)->_lock));
+    if ((_IO_iter_file (i)->_flags & _IO_USER_LOCK) == 0)
+      _IO_lock_init (*((_IO_lock_t *) _IO_iter_file(i)->_lock));
 }