1 files changed, 116 insertions, 0 deletions
diff --git a/nptl/tst-rwlock15.c b/nptl/tst-rwlock15.c
new file mode 100644
index 0000000000..b292701e21
--- /dev/null
+++ b/nptl/tst-rwlock15.c
@@ -0,0 +1,116 @@
+/* Copyright (C) 2015 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; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This tests that a writer that is preferred -- but times out due to a
+   reader being present -- does not miss to wake other readers blocked on the
+   writer's pending lock acquisition.  */
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+/* The bug existed in the code that strictly prefers writers over readers.  */
+static pthread_rwlock_t r = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP;
+
+static void *
+writer (void *arg)
+{
+  struct timespec ts;
+  if (clock_gettime (CLOCK_REALTIME, &ts) != 0)
+    {
+      puts ("clock_gettime failed");
+      exit (EXIT_FAILURE);
+    }
+  ts.tv_sec += 1;
+  int e = pthread_rwlock_timedwrlock (&r, &ts);
+  if (e != ETIMEDOUT)
+    {
+      puts ("timedwrlock did not time out");
+      exit (EXIT_FAILURE);
+    }
+  return NULL;
+}
+
+static void *
+reader (void *arg)
+{
+  /* This isn't a reliable way to get the interleaving we need (because a
+     failed trylock doesn't synchronize with the writer, and because we could
+     try to lock after the writer has already timed out).  However, both will
+     just lead to false positives.  */
+  int e;
+  while ((e = pthread_rwlock_tryrdlock (&r)) != EBUSY)
+    {
+      if (e != 0)
+	exit (EXIT_FAILURE);
+      pthread_rwlock_unlock (&r);
+    }
+  e = pthread_rwlock_rdlock (&r);
+  if (e != 0)
+    {
+      puts ("reader rdlock failed");
+      exit (EXIT_FAILURE);
+    }
+  pthread_rwlock_unlock (&r);
+  return NULL;
+}
+
+
+static int
+do_test (void)
+{
+  /* Grab a rdlock, then create a writer and a reader, and wait until they
+     finished.  */
+
+  if (pthread_rwlock_rdlock (&r) != 0)
+    {
+      puts ("initial rdlock failed");
+      return 1;
+    }
+
+  pthread_t thw;
+  if (pthread_create (&thw, NULL, writer, NULL) != 0)
+    {
+      puts ("create failed");
+      return 1;
+    }
+  pthread_t thr;
+  if (pthread_create (&thr, NULL, reader, NULL) != 0)
+    {
+      puts ("create failed");
+      return 1;
+    }
+
+  if (pthread_join (thw, NULL) != 0)
+    {
+      puts ("writer join failed");
+      return 1;
+    }
+  if (pthread_join (thr, NULL) != 0)
+    {
+      puts ("reader join failed");
+      return 1;
+    }
+
+  return 0;
+}
+
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"