projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| f21e8f8c | 1 | /* Test rwlock with PREFER_WRITER_NONRECURSIVE_NP (bug 23861). |
| 04277e02 | 2 | Copyright (C) 2018-2019 Free Software Foundation, Inc. |
| f21e8f8c AS |
3 | This file is part of the GNU C Library. |
| 4 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | |
| 6 | modify it under the terms of the GNU Lesser General Public | |
| 7 | License as published by the Free Software Foundation; either | |
| 8 | version 2.1 of the License, or (at your option) any later version. | |
| 9 | ||
| 10 | The GNU C Library is distributed in the hope that it will be useful, | |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 | Lesser General Public License for more details. | |
| 14 | ||
| 15 | You should have received a copy of the GNU Lesser General Public | |
| 16 | License along with the GNU C Library; if not, see | |
| 5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
| f21e8f8c AS |
18 | |
| 19 | #include <stdio.h> | |
| 20 | #include <stdlib.h> | |
| 21 | #include <unistd.h> | |
| 22 | #include <pthread.h> | |
| 23 | #include <support/xthread.h> | |
| 24 | ||
| 25 | /* We choose 10 iterations because this happens to be able to trigger the | |
| 26 | stall on contemporary hardware. */ | |
| 27 | #define LOOPS 10 | |
| 28 | /* We need 3 threads to trigger bug 23861. One thread as a writer, and | |
| 29 | two reader threads. The test verifies that the second-to-last reader | |
| 30 | is able to notify the *last* reader that it should be done waiting. | |
| 31 | If the second-to-last reader fails to notify the last reader or does | |
| 32 | so incorrectly then the last reader may stall indefinitely. */ | |
| 33 | #define NTHREADS 3 | |
| 34 | ||
| 35 | _Atomic int do_exit; | |
| 36 | pthread_rwlockattr_t mylock_attr; | |
| 37 | pthread_rwlock_t mylock; | |
| 38 | ||
| 39 | void * | |
| 40 | run_loop (void *a) | |
| 41 | { | |
| 42 | while (!do_exit) | |
| 43 | { | |
| 44 | if (random () & 1) | |
| 45 | { | |
| 46 | xpthread_rwlock_wrlock (&mylock); | |
| 47 | xpthread_rwlock_unlock (&mylock); | |
| 48 | } | |
| 49 | else | |
| 50 | { | |
| 51 | xpthread_rwlock_rdlock (&mylock); | |
| 52 | xpthread_rwlock_unlock (&mylock); | |
| 53 | } | |
| 54 | } | |
| 55 | return NULL; | |
| 56 | } | |
| 57 | ||
| 58 | int | |
| 59 | do_test (void) | |
| 60 | { | |
| 61 | xpthread_rwlockattr_init (&mylock_attr); | |
| 62 | xpthread_rwlockattr_setkind_np (&mylock_attr, | |
| 63 | PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP); | |
| 64 | xpthread_rwlock_init (&mylock, &mylock_attr); | |
| 65 | ||
| 66 | for (int n = 0; n < LOOPS; n++) | |
| 67 | { | |
| 68 | pthread_t tids[NTHREADS]; | |
| 69 | do_exit = 0; | |
| 70 | for (int i = 0; i < NTHREADS; i++) | |
| 71 | tids[i] = xpthread_create (NULL, run_loop, NULL); | |
| 72 | /* Let the threads run for some time. */ | |
| 73 | sleep (1); | |
| 74 | printf ("Exiting..."); | |
| 75 | fflush (stdout); | |
| 76 | do_exit = 1; | |
| 77 | for (int i = 0; i < NTHREADS; i++) | |
| 78 | xpthread_join (tids[i]); | |
| 79 | printf ("done.\n"); | |
| 80 | } | |
| 81 | pthread_rwlock_destroy (&mylock); | |
| 82 | pthread_rwlockattr_destroy (&mylock_attr); | |
| 83 | return 0; | |
| 84 | } | |
| 85 | ||
| 86 | #define TIMEOUT (DEFAULT_TIMEOUT + 3 * LOOPS) | |
| 87 | #include <support/test-driver.c> |