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[PATCH] Fix generic __lll_robust_timedlock_wait to check for timeout (bug 20263)


When commit 8f86154 added support for FUTEX_WAIT_BITSET it didn't add a
check for timeout from lll_futex_timed_wait_bitset in
__lll_robust_timedlock_wait.  This only became a problem once glibc is
configured for kernel >= 2.6.29 (which is now always the case).  Since
__ASSUME_FUTEX_CLOCK_REALTIME is now always defined the fallback code is
no longer needed.  Tested on aarch64.

Andreas.

	[BZ #20263]
	* nptl/lowlevelrobustlock.c (__lll_robust_timedlock_wait): Check
	for ETIMEDOUT or EINVAL.
	[__ASSUME_FUTEX_CLOCK_REALTIME]: Remove conditional code.
	* nptl/tst-robust10.c: New test.
	* nptl/Makefile (tests): Add tst-robust10.
---
 nptl/Makefile             |   2 +-
 nptl/lowlevelrobustlock.c |  34 ++------------
 nptl/tst-robust10.c       | 110 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+), 31 deletions(-)
 create mode 100644 nptl/tst-robust10.c

diff --git a/nptl/Makefile b/nptl/Makefile
index e0bc1b7..28f6d5a 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -290,7 +290,7 @@ tests = tst-typesizes \
 	tst-initializers1 $(addprefix tst-initializers1-,\
 			    c89 gnu89 c99 gnu99 c11 gnu11) \
 	tst-bad-schedattr \
-	tst-thread_local1 tst-mutex-errorcheck
+	tst-thread_local1 tst-mutex-errorcheck tst-robust10
 xtests = tst-setuid1 tst-setuid1-static tst-setuid2 \
 	tst-mutexpp1 tst-mutexpp6 tst-mutexpp10
 test-srcs = tst-oddstacklimit
diff --git a/nptl/lowlevelrobustlock.c b/nptl/lowlevelrobustlock.c
index 3b988b2..2083979 100644
--- a/nptl/lowlevelrobustlock.c
+++ b/nptl/lowlevelrobustlock.c
@@ -21,7 +21,6 @@
 #include <lowlevellock.h>
 #include <sys/time.h>
 #include <pthreadP.h>
-#include <kernel-features.h>
 
 
 int
@@ -81,28 +80,6 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
 
   do
     {
-#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
-     || !defined lll_futex_timed_wait_bitset)
-      struct timeval tv;
-      struct timespec rt;
-
-      /* Get the current time.  */
-      (void) __gettimeofday (&tv, NULL);
-
-      /* Compute relative timeout.  */
-      rt.tv_sec = abstime->tv_sec - tv.tv_sec;
-      rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
-      if (rt.tv_nsec < 0)
-	{
-	  rt.tv_nsec += 1000000000;
-	  --rt.tv_sec;
-	}
-
-      /* Already timed out?  */
-      if (rt.tv_sec < 0)
-	return ETIMEDOUT;
-#endif
-
       /* If the owner died, return the present value of the futex.  */
       if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))
 	return oldval;
@@ -114,13 +91,10 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
 	continue;
 
       /* If *futex == 2, wait until woken or timeout.  */
-#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
-     || !defined lll_futex_timed_wait_bitset)
-      lll_futex_timed_wait (futex, newval, &rt, private);
-#else
-      lll_futex_timed_wait_bitset (futex, newval, abstime,
-				   FUTEX_CLOCK_REALTIME, private);
-#endif
+      int err = lll_futex_timed_wait_bitset (futex, newval, abstime,
+					     FUTEX_CLOCK_REALTIME, private);
+      if (err == -ETIMEDOUT || err == -EINVAL)
+	return -err;
 
     try:
       ;
diff --git a/nptl/tst-robust10.c b/nptl/tst-robust10.c
new file mode 100644
index 0000000..6d9e502
--- /dev/null
+++ b/nptl/tst-robust10.c
@@ -0,0 +1,110 @@
+/* Test that pthread_mutex_timedlock properly times out.
+   Copyright (C) 2016 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/>.  */
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+pthread_mutex_t mutex;
+
+static void *
+thr (void *arg)
+{
+  struct timespec abstime;
+  clock_gettime (CLOCK_REALTIME, &abstime);
+  abstime.tv_sec += 1;
+  int ret = pthread_mutex_timedlock (&mutex, &abstime);
+  if (ret == 0)
+    {
+      puts ("mutex_timedlock didn't fail");
+      exit (1);
+    }
+  if (ret != ETIMEDOUT)
+    {
+      printf ("mutex_timedlock failed: %s\n", strerror (ret));
+      exit (1);
+    }
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  pthread_t pt;
+  pthread_mutexattr_t ma;
+
+  if (pthread_mutexattr_init (&ma) != 0)
+    {
+      puts ("mutexattr_init failed");
+      return 0;
+    }
+  if (pthread_mutexattr_setrobust_np (&ma, PTHREAD_MUTEX_ROBUST_NP) != 0)
+    {
+      puts ("mutexattr_setrobust failed");
+      return 1;
+    }
+  if (pthread_mutex_init (&mutex, &ma))
+    {
+      puts ("mutex_init failed");
+      return 1;
+    }
+
+  if (pthread_mutexattr_destroy (&ma))
+    {
+      puts ("mutexattr_destroy failed");
+      return 1;
+    }
+
+  if (pthread_mutex_lock (&mutex))
+    {
+      puts ("mutex_lock failed");
+      return 1;
+    }
+
+  if (pthread_create (&pt, NULL, thr, NULL))
+    {
+      puts ("pthread_create failed");
+      return 1;
+    }
+
+  if (pthread_join (pt, NULL))
+    {
+      puts ("pthread_join failed");
+      return 1;
+    }
+
+  if (pthread_mutex_unlock (&mutex))
+    {
+      puts ("mutex_unlock failed");
+      return 1;
+    }
+
+  if (pthread_mutex_destroy (&mutex))
+    {
+      puts ("mutex_destroy failed");
+      return 1;
+    }
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
-- 
2.9.0


-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."


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