[PATCH glibc 3/3] rseq registration tests (v10)

[Mathieu Desnoyers via Libc-alpha <libc-alpha@sourceware.org>]

These tests validate that rseq is registered from various execution
contexts (main thread, constructor, destructor, other threads, other
threads created from constructor and destructor, forked process
(without exec), pthread_atfork handlers, pthread setspecific
destructors, C++ thread and process destructors, signal handlers,
atexit handlers).

tst-rseq.c only links against libc.so, testing registration of rseq in
a non-multithreaded environment.

tst-rseq-nptl.c also links against libpthread.so, testing registration
of rseq in a multithreaded environment.

See the Linux kernel selftests for extensive rseq stress-tests.

CC: Carlos O'Donell <carlos@redhat.com>
CC: Florian Weimer <fweimer@redhat.com>
CC: Joseph Myers <joseph@codesourcery.com>
CC: Szabolcs Nagy <szabolcs.nagy@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ben Maurer <bmaurer@fb.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Paul Turner <pjt@google.com>
CC: libc-alpha@sourceware.org
---
Changes since v1:
- Rename tst-rseq.c to tst-rseq-nptl.c.
- Introduce tst-rseq.c testing rseq registration in a non-multithreaded
  environment.

Chances since v2:
- Update file headers.
- use xpthread key create/delete.
- remove set stacksize.
- Tests depend on both __NR_rseq and RSEQ_SIG being defined.

Changes since v3:
- Update ChangeLog.

Changes since v4:
- Remove volatile from sys_rseq() rseq_abi parameter.
- Use atomic_load_relaxed to load __rseq_abi.cpu_id, consequence of the
  fact that __rseq_abi is not volatile anymore.
- Include atomic.h from tst-rseq.c for use of atomic_load_relaxed.
  Move tst-rseq.c to internal tests within Makefile due to its use of
  atomic.h.
- Test __rseq_handled initialization by glibc.

Changes since v5:
- Rebase on glibc 2.30.

Changes since v6:
- Remove __rseq_handled.

Changes since v7:
- Update copyright range to include 2020.
- Use __ASSUME_RSEQ to detect rseq availability.

Changes since v8:
- Remove use of __ASSUME_RSEQ.

Changes since v9:
- Adapt to new prototype for xpthread_key_create.
- Update copyright year to 2020.
- Remove constructor test (moved to later patch due to test harness
  modification dependency).
- Change http:// for https://.
---
 sysdeps/unix/sysv/linux/Makefile        |   6 +-
 sysdeps/unix/sysv/linux/tst-rseq-nptl.c | 338 ++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/tst-rseq.c      | 108 ++++++++
 3 files changed, 450 insertions(+), 2 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/tst-rseq-nptl.c
 create mode 100644 sysdeps/unix/sysv/linux/tst-rseq.c

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index e3ed374d9e..598c0ecfdd 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -100,7 +100,9 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
 	 test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \
 	 tst-rlimit-infinity tst-ofdlocks tst-gettid tst-gettid-kill \
 	 tst-tgkill
-tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
+
+tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc \
+		  tst-ofdlocks-compat tst-rseq
 
 CFLAGS-tst-sigcontext-get_pc.c = -fasynchronous-unwind-tables
 
@@ -303,5 +305,5 @@ ifeq ($(subdir),nptl)
 tests += tst-align-clone tst-getpid1 \
 	tst-thread-affinity-pthread tst-thread-affinity-pthread2 \
 	tst-thread-affinity-sched
-tests-internal += tst-setgetname
+tests-internal += tst-setgetname tst-rseq-nptl
 endif
diff --git a/sysdeps/unix/sysv/linux/tst-rseq-nptl.c b/sysdeps/unix/sysv/linux/tst-rseq-nptl.c
new file mode 100644
index 0000000000..3e3996d686
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-rseq-nptl.c
@@ -0,0 +1,338 @@
+/* Restartable Sequences NPTL test.
+
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   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
+   <https://www.gnu.org/licenses/>.  */
+
+/* These tests validate that rseq is registered from various execution
+   contexts (main thread, destructor, other threads, other threads created
+   from destructor, forked process (without exec), pthread_atfork handlers,
+   pthread setspecific destructors, C++ thread and process destructors,
+   signal handlers, atexit handlers).
+
+   See the Linux kernel selftests for extensive rseq stress-tests.  */
+
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/xthread.h>
+#include <sys/rseq.h>
+
+#ifdef RSEQ_SIG
+#include <pthread.h>
+#include <syscall.h>
+#include <stdlib.h>
+#include <error.h>
+#include <errno.h>
+#include <string.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <atomic.h>
+
+static pthread_key_t rseq_test_key;
+
+static int
+rseq_thread_registered (void)
+{
+  return (int32_t) atomic_load_relaxed (&__rseq_abi.cpu_id) >= 0;
+}
+
+static void
+atfork_prepare (void)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in pthread atfork prepare\n");
+      support_record_failure ();
+    }
+}
+
+static void
+atfork_parent (void)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in pthread atfork parent\n");
+      support_record_failure ();
+    }
+}
+
+static void
+atfork_child (void)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in pthread atfork child\n");
+      support_record_failure ();
+    }
+}
+
+static void
+rseq_key_destructor (void *arg)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (!rseq_thread_registered ())
+    FAIL_EXIT1 ("rseq not registered in pthread key destructor");
+}
+
+static void
+atexit_handler (void)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (!rseq_thread_registered ())
+    FAIL_EXIT1 ("rseq not registered in atexit handler");
+}
+
+static int
+do_rseq_main_test (void)
+{
+  if (atexit (atexit_handler))
+    FAIL_EXIT1 ("error calling atexit");
+  rseq_test_key = xpthread_key_create (rseq_key_destructor);
+  if (pthread_atfork (atfork_prepare, atfork_parent, atfork_child))
+    FAIL_EXIT1 ("error calling pthread_atfork");
+  if (raise (SIGUSR1))
+    FAIL_EXIT1 ("error raising signal");
+  if (pthread_setspecific (rseq_test_key, (void *) 1l))
+    FAIL_EXIT1 ("error in pthread_setspecific");
+  if (!rseq_thread_registered ())
+    {
+      FAIL_RET ("rseq not registered in main thread");
+    }
+  return 0;
+}
+
+static void
+cancel_routine (void *arg)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in cancel routine\n");
+      support_record_failure ();
+    }
+}
+
+static int cancel_thread_ready;
+
+static void
+test_cancel_thread (void)
+{
+  pthread_cleanup_push (cancel_routine, NULL);
+  atomic_store_release (&cancel_thread_ready, 1);
+  for (;;)
+    usleep (100);
+  pthread_cleanup_pop (0);
+}
+
+static void *
+thread_function (void * arg)
+{
+  int i = (int) (intptr_t) arg;
+
+  if (raise (SIGUSR1))
+    FAIL_EXIT1 ("error raising signal");
+  if (i == 0)
+    test_cancel_thread ();
+  if (pthread_setspecific (rseq_test_key, (void *) 1l))
+    FAIL_EXIT1 ("error in pthread_setspecific");
+  return rseq_thread_registered () ? NULL : (void *) 1l;
+}
+
+static void
+sighandler (int sig)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in signal handler\n");
+      support_record_failure ();
+    }
+}
+
+static void
+setup_signals (void)
+{
+  struct sigaction sa;
+
+  sigemptyset (&sa.sa_mask);
+  sigaddset (&sa.sa_mask, SIGUSR1);
+  sa.sa_flags = 0;
+  sa.sa_handler = sighandler;
+  if (sigaction (SIGUSR1, &sa, NULL) != 0)
+    {
+      FAIL_EXIT1 ("sigaction failure: %s", strerror (errno));
+    }
+}
+
+#define N 7
+static const int t[N] = { 1, 2, 6, 5, 4, 3, 50 };
+
+static int
+do_rseq_threads_test (int nr_threads)
+{
+  pthread_t th[nr_threads];
+  int i;
+  int result = 0;
+
+  cancel_thread_ready = 0;
+  for (i = 0; i < nr_threads; ++i)
+    if (pthread_create (&th[i], NULL, thread_function,
+                        (void *) (intptr_t) i) != 0)
+      {
+        FAIL_EXIT1 ("creation of thread %d failed", i);
+      }
+
+  while (!atomic_load_acquire (&cancel_thread_ready))
+    usleep (100);
+
+  if (pthread_cancel (th[0]))
+    FAIL_EXIT1 ("error in pthread_cancel");
+
+  for (i = 0; i < nr_threads; ++i)
+    {
+      void *v;
+      if (pthread_join (th[i], &v) != 0)
+        {
+          printf ("join of thread %d failed\n", i);
+          result = 1;
+        }
+      else if (i != 0 && v != NULL)
+        {
+          printf ("join %d successful, but child failed\n", i);
+          result = 1;
+        }
+      else if (i == 0 && v == NULL)
+        {
+          printf ("join %d successful, child did not fail as expected\n", i);
+          result = 1;
+        }
+    }
+  return result;
+}
+
+static int
+sys_rseq (struct rseq *rseq_abi, uint32_t rseq_len, int flags, uint32_t sig)
+{
+  return syscall (__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+static int
+rseq_available (void)
+{
+  int rc;
+
+  rc = sys_rseq (NULL, 0, 0, 0);
+  if (rc != -1)
+    FAIL_EXIT1 ("Unexpected rseq return value %d", rc);
+  switch (errno)
+    {
+    case ENOSYS:
+      return 0;
+    case EINVAL:
+      return 1;
+    default:
+      FAIL_EXIT1 ("Unexpected rseq error %s", strerror (errno));
+    }
+}
+
+static int
+do_rseq_fork_test (void)
+{
+  int status;
+  pid_t pid, retpid;
+
+  pid = fork ();
+  switch (pid)
+    {
+      case 0:
+        exit (do_rseq_main_test ());
+      case -1:
+        FAIL_EXIT1 ("Unexpected fork error %s", strerror (errno));
+    }
+  retpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0));
+  if (retpid != pid)
+    {
+      FAIL_EXIT1 ("waitpid returned %ld, expected %ld",
+                  (long int) retpid, (long int) pid);
+    }
+  if (WEXITSTATUS (status))
+    {
+      printf ("rseq not registered in child\n");
+      return 1;
+    }
+  return 0;
+}
+
+static int
+do_rseq_test (void)
+{
+  int i, result = 0;
+
+  if (!rseq_available ())
+    {
+      FAIL_UNSUPPORTED ("kernel does not support rseq, skipping test");
+    }
+  setup_signals ();
+  if (raise (SIGUSR1))
+    FAIL_EXIT1 ("error raising signal");
+  if (do_rseq_main_test ())
+    result = 1;
+  for (i = 0; i < N; i++)
+    {
+      if (do_rseq_threads_test (t[i]))
+        result = 1;
+    }
+  if (do_rseq_fork_test ())
+    result = 1;
+  return result;
+}
+
+static void __attribute__ ((destructor))
+do_rseq_destructor_test (void)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (do_rseq_test ())
+    FAIL_EXIT1 ("rseq not registered within destructor");
+  xpthread_key_delete (rseq_test_key);
+}
+
+/* Test C++ destructor called at thread and process exit.  */
+void
+__call_tls_dtors (void)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (!rseq_thread_registered ())
+    FAIL_EXIT1 ("rseq not registered in C++ thread/process exit destructor");
+}
+#else
+static int
+do_rseq_test (void)
+{
+#ifndef RSEQ_SIG
+  FAIL_UNSUPPORTED ("glibc does not define RSEQ_SIG, skipping test");
+#endif
+  return 0;
+}
+#endif
+
+static int
+do_test (void)
+{
+  return do_rseq_test ();
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/tst-rseq.c b/sysdeps/unix/sysv/linux/tst-rseq.c
new file mode 100644
index 0000000000..48a61f9998
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-rseq.c
@@ -0,0 +1,108 @@
+/* Restartable Sequences single-threaded tests.
+
+   Copyright (C) 2020 Free Software Foundation, Inc.
+
+   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
+   <https://www.gnu.org/licenses/>.  */
+
+/* These tests validate that rseq is registered from main in an executable
+   not linked against libpthread.  */
+
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <sys/rseq.h>
+
+#ifdef RSEQ_SIG
+#include <syscall.h>
+#include <stdlib.h>
+#include <error.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+#include <atomic.h>
+
+static int
+rseq_thread_registered (void)
+{
+  return (int32_t) atomic_load_relaxed (&__rseq_abi.cpu_id) >= 0;
+}
+
+static int
+do_rseq_main_test (void)
+{
+  if (!rseq_thread_registered ())
+    {
+      FAIL_RET ("rseq not registered in main thread");
+    }
+  return 0;
+}
+
+static int
+sys_rseq (struct rseq *rseq_abi, uint32_t rseq_len, int flags, uint32_t sig)
+{
+  return syscall (__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+static int
+rseq_available (void)
+{
+  int rc;
+
+  rc = sys_rseq (NULL, 0, 0, 0);
+  if (rc != -1)
+    FAIL_EXIT1 ("Unexpected rseq return value %d", rc);
+  switch (errno)
+    {
+    case ENOSYS:
+      return 0;
+    case EINVAL:
+      return 1;
+    default:
+      FAIL_EXIT1 ("Unexpected rseq error %s", strerror (errno));
+    }
+}
+
+static int
+do_rseq_test (void)
+{
+  int result = 0;
+
+  if (!rseq_available ())
+    {
+      FAIL_UNSUPPORTED ("kernel does not support rseq, skipping test");
+    }
+  if (do_rseq_main_test ())
+    result = 1;
+  return result;
+}
+#else
+static int
+do_rseq_test (void)
+{
+#ifndef RSEQ_SIG
+  FAIL_UNSUPPORTED ("glibc does not define RSEQ_SIG, skipping test");
+#endif
+  return 0;
+}
+#endif
+
+static int
+do_test (void)
+{
+  return do_rseq_test ();
+}
+
+#include <support/test-driver.c>
-- 
2.17.1