diff --git a/ChangeLog b/ChangeLog
index 029c2a265a..1921f8883b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2017-10-11  Luke Shumaker  <lukeshu@parabola.nu>
 
+	[BZ #22145]
+	* sysdeps/unix/sysv/linux/tst-ttyname.c: New file.
+	* sysdeps/unix/sysv/linux/Makefile: Add tst-ttyname to tests.
+
 	* sysdeps/unix/sysv/linux/ttyname.h (is_pty): Update doc reference.
 
 	* manual/terminal.texi: Mention ENODEV for ttyname and ttyname_r.
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 30bd167bae..dcd9208352 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -50,7 +50,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
 		  bits/siginfo-arch.h bits/siginfo-consts-arch.h
 
 tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
-	 tst-quota tst-sync_file_range test-errno-linux
+	 tst-quota tst-sync_file_range tst-ttyname test-errno-linux
 
 # Generate the list of SYS_* macros for the system calls (__NR_*
 # macros).  The file syscall-names.list contains all possible system
diff --git a/sysdeps/unix/sysv/linux/tst-ttyname.c b/sysdeps/unix/sysv/linux/tst-ttyname.c
new file mode 100644
index 0000000000..884e498d35
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-ttyname.c
@@ -0,0 +1,325 @@
+/* Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <support/check.h>
+#include <support/namespace.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/test-driver.h>
+#include <support/xunistd.h>
+
+#define PREPARE prepare
+
+#define VERIFY(expr)					\
+  ({							\
+    if (expr)						\
+      ;							\
+    else						\
+      support_exit_failure_impl				\
+        (1, __FILE__, __LINE__, "%s: %m", #expr);	\
+  })
+
+/* plain ttyname runner */
+
+struct result {
+  const char *name;
+  int err;
+};
+
+static struct result
+run_ttyname (int fd)
+{
+  struct result ret;
+  errno = 0;
+  ret.name = ttyname (fd);
+  ret.err = errno;
+  return ret;
+}
+
+static bool
+eq_ttyname (struct result actual, struct result expected)
+{
+  if ((actual.err == expected.err) &&
+      (!actual.name == !expected.name) &&
+      (actual.name ? strcmp (actual.name, expected.name) == 0 : true))
+    {
+      char *name = expected.name
+	? xasprintf("\"%s\"", expected.name)
+	: strdup("NULL");
+      printf ("info: PASS {name=%s, errno=%d}\n",
+	      name, expected.err);
+      free(name);
+      return true;
+    }
+
+  char *actual_name = actual.name
+    ? xasprintf("\"%s\"", actual.name)
+    : strdup("NULL");
+  char *expected_name = expected.name
+    ? xasprintf("\"%s\"", expected.name)
+    : strdup("NULL");
+  printf ("error: actual {name=%s, errno=%d} != expected {name=%s, errno=%d}\n",
+	  actual_name, actual.err,
+	  expected_name, expected.err);
+  free(actual_name);
+  free(expected_name);
+  return false;
+}
+
+/* ttyname_r runner */
+
+struct result_r {
+  const char *name;
+  int ret;
+  int err;
+};
+
+static struct result_r
+run_ttyname_r (int fd)
+{
+  static char buf[TTY_NAME_MAX];
+
+  struct result_r ret;
+  errno = 0;
+  ret.ret = ttyname_r (fd, buf, TTY_NAME_MAX);
+  ret.err = errno;
+  if (ret.ret == 0)
+    ret.name = buf;
+  else
+    ret.name = NULL;
+  return ret;
+}
+
+static bool
+eq_ttyname_r (struct result_r actual, struct result_r expected)
+{
+  if ((actual.err == expected.err) &&
+      (actual.ret == expected.ret) &&
+      (!actual.name == !expected.name) &&
+      (actual.name ? strcmp (actual.name, expected.name) == 0 : true))
+    {
+      char *name = expected.name
+	? xasprintf("\"%s\"", expected.name)
+	: strdup("NULL");
+      printf ("info: PASS {name=%s, ret=%d, errno=%d}\n",
+              name, expected.ret, expected.err);
+      free(name);
+      return true;
+    }
+
+  char *actual_name = actual.name
+    ? xasprintf("\"%s\"", actual.name)
+    : strdup("NULL");
+  char *expected_name = expected.name
+    ? xasprintf("\"%s\"", expected.name)
+    : strdup("NULL");
+  printf ("error: actual {name=%s, ret=%d, errno=%d} != expected {name=%s, ret=%d, errno=%d}\n",
+	  actual_name, actual.ret, actual.err,
+	  expected_name, expected.ret, expected.err);
+  free(actual_name);
+  free(expected_name);
+  return false;
+}
+
+/* combined runner */
+
+static bool
+doit (int fd, const char *testname, struct result_r expected_r) {
+  struct result expected = {.name=expected_r.name, .err=expected_r.ret};
+  bool ret = true;
+
+  printf ("info: running %s\n", testname);
+
+  ret = eq_ttyname (run_ttyname (fd), expected) && ret;
+  ret = eq_ttyname_r (run_ttyname_r (fd), expected_r) && ret;
+
+  return ret;
+}
+
+/* main test */
+
+static char *chrootdir;
+static uid_t orig_uid;
+static uid_t orig_gid;
+
+static void
+prepare (int argc, char **argv)
+{
+  chrootdir = xasprintf ("%s/tst-ttyname-XXXXXX", test_dir);
+  if (mkdtemp (chrootdir) == NULL)
+    FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", chrootdir);
+  add_temp_file (chrootdir);
+
+  orig_uid = getuid();
+  orig_gid = getgid();
+}
+
+static int
+do_test (void)
+{
+  struct stat st;
+
+  /* Open the PTS that we'll be testing on. */
+  int master;
+  char *slavename;
+  VERIFY ((master = posix_openpt (O_RDWR|O_NOCTTY|O_NONBLOCK)) >= 0);
+  VERIFY ((slavename = ptsname (master)));
+  VERIFY (unlockpt (master) == 0);
+  if (strncmp (slavename, "/dev/pts/", 9) != 0)
+    FAIL_UNSUPPORTED ("slave pseudo-terminal is not under /dev/pts/: %s",
+		      slavename);
+  int slave = xopen (slavename, O_RDWR, 0);
+
+  /* Do a basic smoke test */
+
+  if (!doit (slave, "basic smoketest",
+	     (struct result_r){.name=slavename, .ret=0, .err=0}))
+    return 1;
+
+  /* Do the rest in a new mount namespace. */
+
+  support_become_root ();
+  if (unshare (CLONE_NEWNS) < 0)
+    FAIL_UNSUPPORTED ("could not enter new mount namespace");
+  /* support_become_root might have put us in a new user namespace;
+     most filesystems (including tmpfs) don't allow file or directory
+     creation from a user namespace unless uid and gid maps are set,
+     even if we have root privileges in the namespace.
+
+     Also, stat always reports that uid and gid maps are empty, so we
+     have to try actually reading from them to check if they are
+     empty. */
+  int fd;
+  if ((fd = open("/proc/self/uid_map", O_RDWR, 0)) >= 0)
+    {
+      char buf;
+      if (read(fd, &buf, 1) == 0)
+	{
+	  char *str = xasprintf ("0 %ld 1\n", (long)orig_uid);
+	  if (write(fd, str, strlen(str)) < 0)
+	    FAIL_EXIT1("write(uid_map, \"%s\"): %m", str);
+	  free(str);
+	}
+      xclose (fd);
+    }
+  /* oh, but we can't set the gid map until we turn off setgroups */
+  if ((fd = open ("/proc/self/setgroups", O_WRONLY, 0)) >= 0)
+    {
+      const char *str = "deny";
+      if (write(fd, str, strlen(str)) < 0)
+	FAIL_EXIT1("write(setroups, \"%s\"): %m", str);
+      xclose(fd);
+    }
+  if ((fd = open ("/proc/self/gid_map", O_RDWR, 0)) >= 0)
+    {
+      char buf;
+      if (read(fd, &buf, 1) == 0)
+	{
+	  char *str = xasprintf ("0 %ld 1\n", (long)orig_gid);
+	  if (write(fd, str, strlen(str)) < 0)
+	    FAIL_EXIT1("write(gid_map, \"%s\"): %m", str);
+	  free(str);
+	}
+      xclose (fd);
+    }
+
+  /* Set up the chroot */
+
+  VERIFY (mount ("tmpfs", chrootdir, "tmpfs", 0, "mode=755") == 0);
+  VERIFY (chdir (chrootdir) == 0);
+
+  xmkdir ("proc", 0755);
+  /* We possibly aren't root, but just have our own user-ns and
+     mount-ns; we'd also need our own pid-ns to mount procfs
+     normally. */
+  VERIFY (mount ("/proc", "proc", NULL, MS_BIND|MS_REC, NULL) == 0);
+
+  xmkdir ("dev", 0755);
+
+  xmkdir ("dev/pts", 0755);
+  VERIFY
+    (mount ("devpts", "dev/pts", "devpts",
+            MS_NOSUID|MS_NOEXEC, "newinstance,ptmxmode=0666,mode=620") == 0);
+  VERIFY (symlink ("pts/ptmx", "dev/ptmx") == 0);
+
+  /* Put the console at "/console" (where it won't be found);
+     explicitly remount it at "/dev/console" later when we run a test
+     we expect to succeed. */
+  xclose (xopen ("console", O_WRONLY|O_CREAT|O_NOCTTY, 0));
+  xclose (xopen ("dev/console", O_WRONLY|O_CREAT|O_NOCTTY, 0));
+  VERIFY (mount (slavename, "console", NULL, MS_BIND, NULL) == 0);
+
+  xchroot (chrootdir);
+  VERIFY (chdir ("/") == 0);
+
+  bool ok = true;
+
+  VERIFY (stat (slavename, &st) < 0); /* sanity check */
+  ok = doit (slave, "no conflict, no match",
+	     (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}) && ok;
+  VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
+  ok = doit (slave, "no conflict, console",
+	     (struct result_r){.name="/dev/console", .ret=0, .err=0}) && ok;
+  VERIFY (umount ("/dev/console") == 0);
+
+  /* keep creating PTYs until we we get a name collision */
+  while (stat (slavename, &st) < 0)
+    posix_openpt (O_RDWR|O_NOCTTY|O_NONBLOCK);
+  VERIFY (stat (slavename, &st) == 0);
+  ok = doit (slave, "conflict, no match",
+	     (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}) && ok;
+  VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
+  ok = doit (slave, "conflict, console",
+	     (struct result_r){.name="/dev/console", .ret=0, .err=0}) && ok;
+  VERIFY (umount ("/dev/console") == 0);
+
+  VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
+  VERIFY (mount ("/console", slavename, NULL, MS_BIND, NULL) == 0);
+  ok = doit (slave, "with bound pts name",
+	     (struct result_r){.name=slavename, .ret=0, .err=0}) && ok;
+  VERIFY (umount (slavename) == 0);
+  VERIFY (umount ("/dev/console") == 0);
+  
+  VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
+  xmkdir ("/oldpts", 0755);
+  VERIFY (mount ("/dev/pts", "/oldpts", NULL, MS_MOVE, NULL) == 0);
+  xclose (xopen ("/dev/pts/trap", O_WRONLY|O_CREAT|O_NOCTTY, 0));
+  char *path = xasprintf("/oldpts/%s", strrchr(slavename, '/')+1);
+  VERIFY (mount (path, "/dev/pts/trap", NULL, MS_BIND, NULL) == 0);
+  free(path);
+  ok = doit (slave, "with search-path trap",
+	     (struct result_r){.name="/dev/console", .ret=0, .err=0}) && ok;
+  VERIFY (umount ("/dev/pts/trap") == 0);
+  VERIFY (unlink ("/dev/pts/trap") == 0);
+  VERIFY (umount ("/dev/console") == 0);
+
+  return ok ? 0 : 1;
+}
+
+#include <support/test-driver.c>
