Re: [PATCH 6/6] nptl: Test case for bug 34546

On 19/08/26 16:35, Florian Weimer wrote:
> Largely auto-generated, using glibc-specific interfaces, and
> following (manually-written) sysdeps/pthread/tst-robust12.c.
> 
> Assisted-by: LLM

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <[email protected]>


> ---
>  nptl/Makefile        |   1 +
>  nptl/tst-mutexpp11.c | 139 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 140 insertions(+)
>  create mode 100644 nptl/tst-mutexpp11.c
> 
> diff --git a/nptl/Makefile b/nptl/Makefile
> index 97a0fb7f65..dc802ae58c 100644
> --- a/nptl/Makefile
> +++ b/nptl/Makefile
> @@ -311,6 +311,7 @@ tests = \
>    tst-mutexpi10 \
>    tst-mutexpi11 \
>    tst-mutexpi12 \
> +  tst-mutexpp11 \
>    tst-once5 \
>    tst-pthread-affinity-inheritance \
>    tst-pthread-attr-affinity \
> diff --git a/nptl/tst-mutexpp11.c b/nptl/tst-mutexpp11.c
> new file mode 100644
> index 0000000000..107a66209a
> --- /dev/null
> +++ b/nptl/tst-mutexpp11.c
> @@ -0,0 +1,139 @@
> +/* Test that PP mutex timedlock timeout restores thread priority (bug 34546).
> +   Copyright (C) 2026 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
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <errno.h>
> +#include <pthread.h>
> +#include <support/check.h>
> +#include <support/timespec.h>
> +#include <support/xthread.h>
> +#include <support/xtime.h>
> +
> +#include "tst-tpp.h"
> +
> +static pthread_mutex_t pp_mutex;
> +static pthread_barrier_t barrier;
> +
> +static void *
> +blocker_thread (void *ignored)
> +{
> +  xpthread_mutex_lock (&pp_mutex);
> +
> +  /* Tell the main thread that the mutex is held.  */
> +  xpthread_barrier_wait (&barrier);
> +
> +  /* Wait for the main thread to finish its test.  */
> +  xpthread_barrier_wait (&barrier);
> +
> +  xpthread_mutex_unlock (&pp_mutex);
> +  return NULL;
> +}
> +
> +/* Used by CHECK_TPP_PRIORITY.  */
> +static int ret;
> +
> +static void
> +test_timedlock (void)
> +{
> +  pthread_t thr = xpthread_create (NULL, blocker_thread, NULL);
> +  xpthread_barrier_wait (&barrier);
> +
> +  CHECK_TPP_PRIORITY (4, 4);
> +
> +  /* Already-expired timeout.  */
> +  static const struct timespec t = { -1, 0 };
> +  TEST_COMPARE (pthread_mutex_timedlock (&pp_mutex, &t), ETIMEDOUT);
> +
> +  /* The timeout error path must restore the thread priority.  */
> +  CHECK_TPP_PRIORITY (4, 4);
> +
> +  xpthread_barrier_wait (&barrier);
> +  xpthread_join (thr);
> +}
> +
> +static void
> +test_clocklock (void)
> +{
> +  pthread_t thr = xpthread_create (NULL, blocker_thread, NULL);
> +  xpthread_barrier_wait (&barrier);
> +
> +  CHECK_TPP_PRIORITY (4, 4);
> +
> +  /* Already-expired timeout, using CLOCK_REALTIME.  */
> +  static const struct timespec t = { -1, 0 };
> +  TEST_COMPARE (pthread_mutex_clocklock (&pp_mutex, CLOCK_REALTIME, &t),
> +                ETIMEDOUT);
> +
> +  CHECK_TPP_PRIORITY (4, 4);
> +
> +  /* Already-expired timeout, using CLOCK_MONOTONIC.  */
> +  TEST_COMPARE (pthread_mutex_clocklock (&pp_mutex, CLOCK_MONOTONIC, &t),
> +                ETIMEDOUT);
> +
> +  CHECK_TPP_PRIORITY (4, 4);
> +
> +  xpthread_barrier_wait (&barrier);
> +  xpthread_join (thr);
> +}
> +
> +static void
> +test_timedlock_late (void)
> +{
> +  pthread_t thr = xpthread_create (NULL, blocker_thread, NULL);
> +  xpthread_barrier_wait (&barrier);
> +
> +  CHECK_TPP_PRIORITY (4, 4);
> +
> +  /* Timeout in the near future: blocks in the kernel before timing out.  */
> +  struct timespec t;
> +  xclock_gettime (CLOCK_REALTIME, &t);
> +  t = timespec_add (t, make_timespec (0, 50 * 1000 * 1000));
> +  TEST_COMPARE (pthread_mutex_timedlock (&pp_mutex, &t), ETIMEDOUT);
> +
> +  CHECK_TPP_PRIORITY (4, 4);
> +
> +  xpthread_barrier_wait (&barrier);
> +  xpthread_join (thr);
> +}
> +
> +static int
> +do_test (void)
> +{
> +  init_tpp_test ();
> +
> +  /* Create the PP mutex.  */
> +  {
> +    pthread_mutexattr_t ma;
> +    xpthread_mutexattr_init (&ma);
> +    xpthread_mutexattr_setprotocol (&ma, PTHREAD_PRIO_PROTECT);
> +    TEST_COMPARE (pthread_mutexattr_setprioceiling (&ma, 6), 0);
> +    xpthread_mutex_init (&pp_mutex, &ma);
> +    xpthread_mutexattr_destroy (&ma);
> +  }
> +
> +  xpthread_barrier_init (&barrier, NULL, 2);
> +  test_timedlock ();
> +  test_clocklock ();
> +  test_timedlock_late ();
> +  xpthread_barrier_destroy (&barrier);
> +
> +  xpthread_mutex_destroy (&pp_mutex);
> +
> +  return ret;
> +}
> +
> +#include <support/test-driver.c>