Annotation of prex-old/usr/test/deadlock/deadlock.c, Revision 1.1
1.1 ! nbrk 1: /*-
! 2: * Copyright (c) 2005, Kohsuke Ohtani
! 3: * All rights reserved.
! 4: *
! 5: * Redistribution and use in source and binary forms, with or without
! 6: * modification, are permitted provided that the following conditions
! 7: * are met:
! 8: * 1. Redistributions of source code must retain the above copyright
! 9: * notice, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice, this list of conditions and the following disclaimer in the
! 12: * documentation and/or other materials provided with the distribution.
! 13: * 3. Neither the name of the author nor the names of any co-contributors
! 14: * may be used to endorse or promote products derived from this software
! 15: * without specific prior written permission.
! 16: *
! 17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
! 18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
! 21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 27: * SUCH DAMAGE.
! 28: */
! 29:
! 30: /*
! 31: * deadlock.c - test program for a kernel deadlock detection.
! 32: */
! 33:
! 34: /*
! 35: * Prex kernel has the feature of deadlock detection. The following
! 36: * senario is tested with this program.
! 37: *
! 38: * 1) Thread-2 locks mutex-A.
! 39: * 2) Thread-1 locks mutex-B.
! 40: * 3) Thread-1 locks mutex-A.
! 41: * 4) Thread-2 locks mutex-B.
! 42: *
! 43: * The deadlock occurs at 4) because mutex-B has been already locked by
! 44: * thread-1 and thread-1 is waiting for thread-2 (mutex-A).
! 45: * The kernel will detect this condition, and the mutex_lock() system
! 46: * call will return EDEADLK error code.
! 47: */
! 48:
! 49: #include <prex/prex.h>
! 50: #include <stdio.h>
! 51: #include <errno.h>
! 52:
! 53: static char stack[2][1024];
! 54: static thread_t th_1, th_2;
! 55: static mutex_t mtx_A, mtx_B;
! 56:
! 57: thread_t
! 58: thread_run(void (*start)(void), void *stack)
! 59: {
! 60: thread_t th;
! 61: int err;
! 62:
! 63: err = thread_create(task_self(), &th);
! 64: if (err)
! 65: panic("thread_create is failed");
! 66:
! 67: err = thread_load(th, start, stack);
! 68: if (err)
! 69: panic("thread_load is failed");
! 70:
! 71: return th;
! 72: }
! 73:
! 74: /*
! 75: * Thread 1 - Priority = 100
! 76: */
! 77: static void
! 78: thread_1(void)
! 79: {
! 80: int err;
! 81:
! 82: printf("thread_1: starting\n");
! 83:
! 84: /*
! 85: * 2) Lock mutex B
! 86: */
! 87: printf("thread_1: 2) lock B\n");
! 88: err = mutex_lock(&mtx_B);
! 89: if (err) printf("err=%d\n", err);
! 90:
! 91: /*
! 92: * 3) Lock mutex A
! 93: *
! 94: * Switch to thread 1.
! 95: */
! 96: printf("thread_1: 3) lock A\n");
! 97: err = mutex_lock(&mtx_A);
! 98: if (err) printf("err=%d\n", err);
! 99:
! 100: printf("thread_1: exit\n");
! 101: thread_terminate(th_1);
! 102: }
! 103:
! 104: /*
! 105: * Thread 2 - Priority = 101
! 106: */
! 107: static void
! 108: thread_2(void)
! 109: {
! 110: int err;
! 111:
! 112: printf("thread_2: starting\n");
! 113:
! 114: /*
! 115: * 1) Lock mutex A
! 116: */
! 117: printf("thread_2: 1) lock A\n");
! 118: err = mutex_lock(&mtx_A);
! 119: if (err) printf("err=%d\n", err);
! 120:
! 121: /*
! 122: * Switch to thread 1
! 123: */
! 124: thread_resume(th_1);
! 125:
! 126: printf("thread_2: running\n");
! 127: /*
! 128: * 4) Lock mutex B
! 129: *
! 130: * Deadlock occurs here!
! 131: */
! 132: printf("thread_2: 4) lock B\n");
! 133: err = mutex_lock(&mtx_B);
! 134: if (err) printf("err=%d\n", err);
! 135: if (err == EDEADLK)
! 136: printf("**** DEADLOCK!! ****\n");
! 137:
! 138: printf("thread_2: exit\n");
! 139: thread_terminate(th_2);
! 140: }
! 141:
! 142: int
! 143: main(int argc, char *argv[])
! 144: {
! 145: printf("Deadlock test program\n");
! 146:
! 147: /*
! 148: * Boost priority of this thread
! 149: */
! 150: thread_setprio(thread_self(), 90);
! 151:
! 152: /*
! 153: * Initialize mutexes.
! 154: */
! 155: mutex_init(&mtx_A);
! 156: mutex_init(&mtx_B);
! 157:
! 158: /*
! 159: * Create new threads
! 160: */
! 161: th_1 = thread_run(thread_1, stack[0]+1024);
! 162: thread_setprio(th_1, 100);
! 163:
! 164: th_2 = thread_run(thread_2, stack[1]+1024);
! 165: thread_setprio(th_2, 101);
! 166:
! 167: /*
! 168: * Start thread 2
! 169: */
! 170: thread_resume(th_2);
! 171:
! 172: /*
! 173: * Wait...
! 174: */
! 175: thread_suspend(thread_self());
! 176:
! 177: return 0;
! 178: }
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