[RFC,v4,5/5] rseq registration tests

  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, and signal handlers).

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

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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: Dave Watson <davejwatson@fb.com>
CC: Paul Turner <pjt@google.com>
CC: libc-alpha@sourceware.org
---
 nptl/Makefile   |   2 +-
 nptl/tst-rseq.c | 346 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 347 insertions(+), 1 deletion(-)
 create mode 100644 nptl/tst-rseq.c
  

----- On Nov 21, 2018, at 1:39 PM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote:

> 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, and signal handlers).
> 
> See the Linux kernel selftests for extensive rseq stress-tests.

In the next round (v5), I'll also add atexit () callback testing,
which is missing here.

Thanks,

Mathieu

> 
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> 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: Dave Watson <davejwatson@fb.com>
> CC: Paul Turner <pjt@google.com>
> CC: libc-alpha@sourceware.org
> ---
> nptl/Makefile   |   2 +-
> nptl/tst-rseq.c | 346 ++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 347 insertions(+), 1 deletion(-)
> create mode 100644 nptl/tst-rseq.c
> 
> diff --git a/nptl/Makefile b/nptl/Makefile
> index 3a5dc80c65..797309f7a8 100644
> --- a/nptl/Makefile
> +++ b/nptl/Makefile
> @@ -323,7 +323,7 @@ tests = tst-attr1 tst-attr2 tst-attr3 tst-default-attr \
> tests-internal := tst-rwlock19 tst-rwlock20 \
> 		  tst-sem11 tst-sem12 tst-sem13 \
> 		  tst-barrier5 tst-signal7 tst-mutex8 tst-mutex8-static \
> -		  tst-mutexpi8 tst-mutexpi8-static
> +		  tst-mutexpi8 tst-mutexpi8-static tst-rseq
> 
> xtests = tst-setuid1 tst-setuid1-static tst-setuid2 \
> 	tst-mutexpp1 tst-mutexpp6 tst-mutexpp10
> diff --git a/nptl/tst-rseq.c b/nptl/tst-rseq.c
> new file mode 100644
> index 0000000000..c55345e44d
> --- /dev/null
> +++ b/nptl/tst-rseq.c
> @@ -0,0 +1,346 @@
> +/* Copyright (C) 2018 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +   Contributed by Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, 2018.
> +
> +   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/>.  */
> +
> +/* 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, and signal 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>
> +
> +#if defined (__linux__) && defined (__NR_rseq)
> +#define HAS_RSEQ
> +#endif
> +
> +#ifdef HAS_RSEQ
> +#include <linux/rseq.h>
> +#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;
> +
> +extern __thread volatile struct rseq __rseq_abi
> +__attribute__ ((tls_model ("initial-exec")));
> +
> +static int
> +rseq_thread_registered (void)
> +{
> +  return __rseq_abi.cpu_id >= 0;
> +}
> +
> +static int
> +do_rseq_main_test (void)
> +{
> +  if (raise (SIGUSR1))
> +    FAIL_EXIT1 ("error raising signal");
> +  return rseq_thread_registered () ? 0 : 1;
> +}
> +
> +static void
> +cancel_routine (void *arg)
> +{
> +  if (!rseq_thread_registered ())
> +    FAIL_EXIT1 ("rseq not registered in cancel routine");
> +}
> +
> +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 ())
> +    FAIL_EXIT1 ("rseq not registered in signal handler");
> +}
> +
> +static int
> +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_RET ("sigaction failure: %s", strerror (errno));
> +    }
> +  return 0;
> +}
> +
> +#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;
> +  pthread_attr_t at;
> +
> +  if (pthread_attr_init (&at) != 0)
> +    {
> +      FAIL_RET ("attr_init failed");
> +    }
> +
> +  if (pthread_attr_setstacksize (&at, 1 * 1024 * 1024) != 0)
> +    {
> +      FAIL_RET ("attr_setstacksize failed");
> +    }
> +
> +  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);
> +      }
> +
> +  if (pthread_attr_destroy (&at) != 0)
> +    {
> +      FAIL_RET ("attr_destroy failed");
> +    }
> +
> +  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 (volatile 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:
> +        if (do_rseq_main_test ())
> +          FAIL_EXIT1 ("rseq not registered in child");
> +        exit (0);
> +      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);
> +    }
> +  return WEXITSTATUS (status);
> +}
> +
> +static int
> +do_rseq_test (void)
> +{
> +  int i, result = 0;
> +
> +  if (!rseq_available ())
> +    {
> +      FAIL_UNSUPPORTED ("kernel does not support rseq, skipping test");
> +    }
> +  if (setup_signals ())
> +    FAIL_EXIT1 ("error setting up signal handler");
> +  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
> +atfork_prepare (void)
> +{
> +  if (!rseq_thread_registered ())
> +    FAIL_EXIT1 ("rseq not registered in pthread atfork prepare");
> +}
> +
> +static void
> +atfork_parent (void)
> +{
> +  if (!rseq_thread_registered ())
> +    FAIL_EXIT1 ("rseq not registered in pthread atfork parent");
> +}
> +
> +static void
> +atfork_child (void)
> +{
> +  if (!rseq_thread_registered ())
> +    FAIL_EXIT1 ("rseq not registered in pthread atfork child");
> +}
> +
> +static void
> +rseq_key_destructor (void *arg)
> +{
> +  if (!rseq_thread_registered ())
> +    FAIL_EXIT1 ("rseq not registered in pthread key destructor");
> +}
> +
> +static void
> +do_rseq_create_key (void)
> +{
> +  if (pthread_key_create (&rseq_test_key, rseq_key_destructor))
> +    FAIL_EXIT1 ("error in pthread_key_create");
> +}
> +
> +static void
> +do_rseq_delete_key (void)
> +{
> +  if (pthread_key_delete (rseq_test_key))
> +    FAIL_EXIT1 ("error in pthread_key_delete");
> +}
> +
> +static void __attribute__ ((constructor))
> +do_rseq_constructor_test (void)
> +{
> +  support_record_failure_init ();
> +  do_rseq_create_key ();
> +  if (pthread_atfork (atfork_prepare, atfork_parent, atfork_child))
> +    FAIL_EXIT1 ("error calling pthread_atfork");
> +  if (do_rseq_test ())
> +    FAIL_EXIT1 ("rseq not registered within constructor");
> +}
> +
> +static void __attribute__ ((destructor))
> +do_rseq_destructor_test (void)
> +{
> +  if (do_rseq_test ())
> +    FAIL_EXIT1 ("rseq not registered within destructor");
> +  do_rseq_delete_key ();
> +}
> +
> +/* Test C++ destructor called at thread and process exit.  */
> +void
> +__call_tls_dtors (void)
> +{
> +  if (!rseq_thread_registered ())
> +    FAIL_EXIT1 ("rseq not registered in C++ thread/process exit destructor");
> +}
> +#else
> +static int
> +do_rseq_test (void)
> +{
> +  FAIL_UNSUPPORTED ("kernel headers do not support rseq, skipping test");
> +  return 0;
> +}
> +#endif
> +
> +static int
> +do_test (void)
> +{
> +  return do_rseq_test ();
> +}
> +
> +#include <support/test-driver.c>
> --
> 2.17.1