File: [local] / prex / usr / test / deadlock / deadlock.c (download)
Revision 1.1.1.1 (vendor branch), Tue Aug 19 12:47:01 2008 UTC (16 years ago) by nbrk
Branch: MAIN, KOHSUKE
CVS Tags: PREX_0_8_BASE, HEAD Changes since 1.1: +0 -0 lines
Initial import of Prex, Portable Real-time Embedded POSIX microkernel system.
I have totally new directions in my development (more focused on real hardware, not virtual one).
Old hacks are available in prex-old module. They will be carefully re-designed and merged soon.
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/*-
* Copyright (c) 2005, Kohsuke Ohtani
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* deadlock.c - test program for a kernel deadlock detection.
*/
/*
* Prex kernel has the feature of deadlock detection. The following
* senario is tested with this program.
*
* 1) Thread-2 locks mutex-A.
* 2) Thread-1 locks mutex-B.
* 3) Thread-1 locks mutex-A.
* 4) Thread-2 locks mutex-B.
*
* The deadlock occurs at 4) because mutex-B has been already locked by
* thread-1 and thread-1 is waiting for thread-2 (mutex-A).
* The kernel will detect this condition, and the mutex_lock() system
* call will return EDEADLK error code.
*/
#include <prex/prex.h>
#include <stdio.h>
#include <errno.h>
static char stack[2][1024];
static thread_t th_1, th_2;
static mutex_t mtx_A, mtx_B;
thread_t
thread_run(void (*start)(void), void *stack)
{
thread_t th;
int err;
err = thread_create(task_self(), &th);
if (err)
panic("thread_create is failed");
err = thread_load(th, start, stack);
if (err)
panic("thread_load is failed");
return th;
}
/*
* Thread 1 - Priority = 100
*/
static void
thread_1(void)
{
int err;
printf("thread_1: starting\n");
/*
* 2) Lock mutex B
*/
printf("thread_1: 2) lock B\n");
err = mutex_lock(&mtx_B);
if (err) printf("err=%d\n", err);
/*
* 3) Lock mutex A
*
* Switch to thread 1.
*/
printf("thread_1: 3) lock A\n");
err = mutex_lock(&mtx_A);
if (err) printf("err=%d\n", err);
printf("thread_1: exit\n");
thread_terminate(th_1);
}
/*
* Thread 2 - Priority = 101
*/
static void
thread_2(void)
{
int err;
printf("thread_2: starting\n");
/*
* 1) Lock mutex A
*/
printf("thread_2: 1) lock A\n");
err = mutex_lock(&mtx_A);
if (err) printf("err=%d\n", err);
/*
* Switch to thread 1
*/
thread_resume(th_1);
printf("thread_2: running\n");
/*
* 4) Lock mutex B
*
* Deadlock occurs here!
*/
printf("thread_2: 4) lock B\n");
err = mutex_lock(&mtx_B);
if (err) printf("err=%d\n", err);
if (err == EDEADLK)
printf("**** DEADLOCK!! ****\n");
printf("thread_2: exit\n");
thread_terminate(th_2);
}
int
main(int argc, char *argv[])
{
printf("Deadlock test program\n");
/*
* Boost priority of this thread
*/
thread_setprio(thread_self(), 90);
/*
* Initialize mutexes.
*/
mutex_init(&mtx_A);
mutex_init(&mtx_B);
/*
* Create new threads
*/
th_1 = thread_run(thread_1, stack[0]+1024);
thread_setprio(th_1, 100);
th_2 = thread_run(thread_2, stack[1]+1024);
thread_setprio(th_2, 101);
/*
* Start thread 2
*/
thread_resume(th_2);
/*
* Wait...
*/
thread_suspend(thread_self());
return 0;
}