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ac30324c67
This test depends on the "last" function being called in a different thread than the "first" function, as "last" posts a semaphore that "first" is waiting on. However, if pthread_create fails - for example, if running in an older container before the clone3()-in-container-EPERM fixes - exit() is called in the same thread as everything else, the semaphore never gets posted, and first hangs. The fix is to pre-post that semaphore before a single-threaded exit. Reviewed-by: Arjun Shankar <arjun@redhat.com>
93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
/* Test for exit/dlclose race (Bug 22180).
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Copyright (C) 2017-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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/* This file must be run from within a directory called "stdlib". */
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/* This test verifies that when dlopen in one thread races against exit
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in another thread, we don't call registered destructor twice.
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Expected result:
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second
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first
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... clean termination
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <semaphore.h>
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#include <support/check.h>
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#include <support/xdlfcn.h>
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#include <support/xthread.h>
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/* Semaphore to ensure we have a happens-before between the first function
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starting and exit being called. */
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sem_t order1;
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/* Semaphore to ensure we have a happens-before between the second function
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starting and the first function returning. */
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sem_t order2;
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void *
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exit_thread (void *arg)
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{
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/* Wait for the dlclose to start... */
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sem_wait (&order1);
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/* Then try to run the exit sequence which should call all
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__cxa_atexit registered functions and in parallel with
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the executing dlclose(). */
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exit (0);
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}
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void
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last (void)
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{
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/* Let dlclose thread proceed. */
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sem_post (&order2);
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}
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int
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main (void)
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{
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int value;
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void *dso;
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pthread_t thread;
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atexit (last);
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dso = xdlopen ("$ORIGIN/test-dlclose-exit-race-helper.so",
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RTLD_NOW|RTLD_GLOBAL);
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if ((value = pthread_create (&thread, NULL, exit_thread, NULL)) != 0)
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{
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/* If pthread_create fails, then exit() is called in the main
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thread instead of a second thread, so the semaphore post that
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would have happened in 'last' gets blocked behind the call to
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first() - which is waiting on the semaphore, and thus
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hangs. */
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sem_post (&order2);
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errno = value;
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FAIL_EXIT1 ("pthread_create: %m");
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}
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xdlclose (dso);
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xpthread_join (thread);
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FAIL_EXIT1 ("Did not terminate via exit(0) in exit_thread() as expected.");
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}
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