Esempio n. 1
0
int __ast_rwlock_trywrlock(const char *filename, int line, const char *func, ast_rwlock_t *t, const char *name)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt = NULL;
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

	if (t->tracking) {
		lt = ast_get_reentrancy(&t->track);
	}

	if (lt) {
#ifdef HAVE_BKTR
		struct ast_bt tmp;

		/* The implementation of backtrace() may have its own locks.
		 * Capture the backtrace outside of the reentrancy lock to
		 * avoid deadlocks. See ASTERISK-22455. */
		ast_bt_get_addresses(&tmp);

		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->backtrace[lt->reentrancy] = tmp;
			bt = &lt->backtrace[lt->reentrancy];
		}
		ast_reentrancy_unlock(lt);

		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t, bt);
#else
		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t);
#endif
	}
#endif /* DEBUG_THREADS */

	res = pthread_rwlock_trywrlock(&t->lock);

#ifdef DEBUG_THREADS
	if (!res && lt) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = line;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
			lt->reentrancy++;
		}
		ast_reentrancy_unlock(lt);
		ast_mark_lock_acquired(t);
	} else if (lt) {
		ast_mark_lock_failed(t);
	}
#endif /* DEBUG_THREADS */

	return res;
}
Esempio n. 2
0
struct ast_bt *__ast_bt_create(void)
{
    struct ast_bt *bt = ast_std_calloc(1, sizeof(*bt));

    if (!bt) {
        return NULL;
    }
    bt->alloced = 1;

    ast_bt_get_addresses(bt);

    return bt;
}
Esempio n. 3
0
int __ast_rwlock_wrlock(const char *filename, int line, const char *func, ast_rwlock_t *t, const char *name)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt;
	int canlog = strcmp(filename, "logger.c") & t->tracking;
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) && defined(CAN_COMPARE_MUTEX_TO_INIT_VALUE)
	if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
		 /* Don't warn abount uninitialized lock.
		  * Simple try to initialize it.
		  * May be not needed in linux system.
		  */
		res = __ast_rwlock_init(t->tracking, filename, line, func, name, t);
		if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
			__ast_mutex_logger("%s line %d (%s): Error: rwlock '%s' is uninitialized and unable to initialize.\n",
					filename, line, func, name);
			return res;
		}
	}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

	if (t->tracking && !t->track) {
		ast_reentrancy_init(&t->track);
	}
	lt = t->track;

	if (t->tracking) {
#ifdef HAVE_BKTR
		ast_reentrancy_lock(lt);
		if (lt->reentrancy != AST_MAX_REENTRANCY) {
			ast_bt_get_addresses(&lt->backtrace[lt->reentrancy]);
			bt = &lt->backtrace[lt->reentrancy];
		}
		ast_reentrancy_unlock(lt);
		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t, bt);
#else
		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t);
#endif
	}
#endif /* DEBUG_THREADS */

#if defined(DETECT_DEADLOCKS) && defined(DEBUG_THREADS)
	{
		time_t seconds = time(NULL);
		time_t wait_time, reported_wait = 0;
		do {
			res = pthread_rwlock_trywrlock(&t->lock);
			if (res == EBUSY) {
				wait_time = time(NULL) - seconds;
				if (wait_time > reported_wait && (wait_time % 5) == 0) {
					__ast_mutex_logger("%s line %d (%s): Deadlock? waited %d sec for writelock '%s'?\n",
						filename, line, func, (int)wait_time, name);
					if (t->tracking) {
						ast_reentrancy_lock(lt);
#ifdef HAVE_BKTR
						__dump_backtrace(&lt->backtrace[lt->reentrancy], canlog);
#endif
						__ast_mutex_logger("%s line %d (%s): '%s' was locked  here.\n",
								lt->file[lt->reentrancy-1], lt->lineno[lt->reentrancy-1],
								lt->func[lt->reentrancy-1], name);
#ifdef HAVE_BKTR
						__dump_backtrace(&lt->backtrace[lt->reentrancy-1], canlog);
#endif
						ast_reentrancy_unlock(lt);
					}
					reported_wait = wait_time;
				}
				usleep(200);
			}
		} while (res == EBUSY);
	}
#else /* !DETECT_DEADLOCKS || !DEBUG_THREADS */
	res = pthread_rwlock_wrlock(&t->lock);
#endif /* !DETECT_DEADLOCKS || !DEBUG_THREADS */

#ifdef DEBUG_THREADS
	if (!res && t->tracking) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = line;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
			lt->reentrancy++;
		}
		ast_reentrancy_unlock(lt);
		if (t->tracking) {
			ast_mark_lock_acquired(t);
		}
	} else if (t->tracking) {
#ifdef HAVE_BKTR
		if (lt->reentrancy) {
			ast_reentrancy_lock(lt);
			bt = &lt->backtrace[lt->reentrancy-1];
			ast_reentrancy_unlock(lt);
		} else {
			bt = NULL;
		}
		if (t->tracking) {
			ast_remove_lock_info(t, bt);
		}
#else
		if (t->tracking) {
			ast_remove_lock_info(t);
		}
#endif
	}
	if (res) {
		__ast_mutex_logger("%s line %d (%s): Error obtaining write lock: %s\n",
				filename, line, func, strerror(res));
		DO_THREAD_CRASH;
	}
#endif /* DEBUG_THREADS */

	return res;
}
Esempio n. 4
0
int __ast_cond_timedwait(const char *filename, int lineno, const char *func,
				       const char *cond_name, const char *mutex_name, ast_cond_t *cond,
				       ast_mutex_t *t, const struct timespec *abstime)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt;
	int canlog = strcmp(filename, "logger.c") & t->tracking;
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) && defined(CAN_COMPARE_MUTEX_TO_INIT_VALUE)
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
		__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized.\n",
				   filename, lineno, func, mutex_name);
		res = __ast_pthread_mutex_init(t->tracking, filename, lineno, func, mutex_name, t);
		if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
			__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized and unable to initialize.\n",
					 filename, lineno, func, mutex_name);
		}
		return res;
	}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

	if (t->tracking && !t->track) {
		ast_reentrancy_init(&t->track);
	}
	lt = t->track;

	if (t->tracking) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy && (lt->thread[ROFFSET] != pthread_self())) {
			__ast_mutex_logger("%s line %d (%s): attempted unlock mutex '%s' without owning it!\n",
					   filename, lineno, func, mutex_name);
			__ast_mutex_logger("%s line %d (%s): '%s' was locked here.\n",
					   lt->file[ROFFSET], lt->lineno[ROFFSET], lt->func[ROFFSET], mutex_name);
#ifdef HAVE_BKTR
			__dump_backtrace(&lt->backtrace[ROFFSET], canlog);
#endif
			DO_THREAD_CRASH;
		}

		if (--lt->reentrancy < 0) {
			__ast_mutex_logger("%s line %d (%s): mutex '%s' freed more times than we've locked!\n",
					   filename, lineno, func, mutex_name);
			lt->reentrancy = 0;
		}

		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = NULL;
			lt->lineno[lt->reentrancy] = 0;
			lt->func[lt->reentrancy] = NULL;
			lt->thread[lt->reentrancy] = 0;
		}
#ifdef HAVE_BKTR
		if (lt->reentrancy) {
			bt = &lt->backtrace[lt->reentrancy - 1];
		}
#endif
		ast_reentrancy_unlock(lt);

#ifdef HAVE_BKTR
		ast_remove_lock_info(t, bt);
#else
		ast_remove_lock_info(t);
#endif
	}
#endif /* DEBUG_THREADS */

	res = pthread_cond_timedwait(cond, &t->mutex, abstime);

#ifdef DEBUG_THREADS
	if (res && (res != ETIMEDOUT)) {
		__ast_mutex_logger("%s line %d (%s): Error waiting on condition mutex '%s'\n",
				   filename, lineno, func, strerror(res));
		DO_THREAD_CRASH;
	} else if (t->tracking) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = lineno;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
#ifdef HAVE_BKTR
			ast_bt_get_addresses(&lt->backtrace[lt->reentrancy]);
			bt = &lt->backtrace[lt->reentrancy];
#endif
			lt->reentrancy++;
		} else {
			__ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
							   filename, lineno, func, mutex_name);
		}
		ast_reentrancy_unlock(lt);

#ifdef HAVE_BKTR
		ast_store_lock_info(AST_MUTEX, filename, lineno, func, mutex_name, t, bt);
#else
		ast_store_lock_info(AST_MUTEX, filename, lineno, func, mutex_name, t);
#endif
	}
#endif /* DEBUG_THREADS */

	return res;
}
Esempio n. 5
0
int __ast_pthread_mutex_trylock(const char *filename, int lineno, const char *func,
                                              const char* mutex_name, ast_mutex_t *t)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt;
	int canlog = strcmp(filename, "logger.c") & t->tracking;
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) && defined(CAN_COMPARE_MUTEX_TO_INIT_VALUE)
	if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
		/* Don't warn abount uninitialized mutex.
		 * Simple try to initialize it.
		 * May be not needed in linux system.
		 */
		res = __ast_pthread_mutex_init(t->tracking, filename, lineno, func, mutex_name, t);
		if ((t->mutex) == ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
			__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized and unable to initialize.\n",
					 filename, lineno, func, mutex_name);
			return res;
		}
	}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

	if (t->tracking && !t->track) {
		ast_reentrancy_init(&t->track);
	}
	lt = t->track;

	if (t->tracking) {
#ifdef HAVE_BKTR
		ast_reentrancy_lock(lt);
		if (lt->reentrancy != AST_MAX_REENTRANCY) {
			ast_bt_get_addresses(&lt->backtrace[lt->reentrancy]);
			bt = &lt->backtrace[lt->reentrancy];
		}
		ast_reentrancy_unlock(lt);
		ast_store_lock_info(AST_MUTEX, filename, lineno, func, mutex_name, t, bt);
#else
		ast_store_lock_info(AST_MUTEX, filename, lineno, func, mutex_name, t);
#endif
	}
#endif /* DEBUG_THREADS */

	res = pthread_mutex_trylock(&t->mutex);

#ifdef DEBUG_THREADS
	if (t->tracking && !res) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = lineno;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
			lt->reentrancy++;
		} else {
			__ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
					   filename, lineno, func, mutex_name);
		}
		ast_reentrancy_unlock(lt);
		if (t->tracking) {
			ast_mark_lock_acquired(t);
		}
	} else if (t->tracking) {
		ast_mark_lock_failed(t);
	}
#endif /* DEBUG_THREADS */

	return res;
}
Esempio n. 6
0
int __ast_rwlock_timedwrlock(const char *filename, int line, const char *func, ast_rwlock_t *t, const char *name,
	const struct timespec *abs_timeout)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt;
	int canlog = strcmp(filename, "logger.c") & t->tracking;
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) && defined(CAN_COMPARE_MUTEX_TO_INIT_VALUE)
	if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
		 /* Don't warn abount uninitialized lock.
		  * Simple try to initialize it.
		  * May be not needed in linux system.
		  */
		res = __ast_rwlock_init(t->tracking, filename, line, func, name, t);
		if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
			__ast_mutex_logger("%s line %d (%s): Error: rwlock '%s' is uninitialized and unable to initialize.\n",
					filename, line, func, name);
			return res;
		}
	}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */

	if (t->tracking && !t->track) {
		ast_reentrancy_init(&t->track);
	}
	lt = t->track;

	if (t->tracking) {
#ifdef HAVE_BKTR
		ast_reentrancy_lock(lt);
		if (lt->reentrancy != AST_MAX_REENTRANCY) {
			ast_bt_get_addresses(&lt->backtrace[lt->reentrancy]);
			bt = &lt->backtrace[lt->reentrancy];
		}
		ast_reentrancy_unlock(lt);
		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t, bt);
#else
		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t);
#endif
	}
#endif /* DEBUG_THREADS */

#ifdef HAVE_PTHREAD_RWLOCK_TIMEDWRLOCK
	res = pthread_rwlock_timedwrlock(&t->lock, abs_timeout);
#else
	do {
		struct timeval _start = ast_tvnow(), _diff;
		for (;;) {
			if (!(res = pthread_rwlock_trywrlock(&t->lock))) {
				break;
			}
			_diff = ast_tvsub(ast_tvnow(), _start);
			if (_diff.tv_sec > abs_timeout->tv_sec || (_diff.tv_sec == abs_timeout->tv_sec && _diff.tv_usec * 1000 > abs_timeout->tv_nsec)) {
				break;
			}
			usleep(1);
		}
	} while (0);
#endif

#ifdef DEBUG_THREADS
	if (!res && t->tracking) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = line;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
			lt->reentrancy++;
		}
		ast_reentrancy_unlock(lt);
		if (t->tracking) {
			ast_mark_lock_acquired(t);
		}
	} else if (t->tracking) {
#ifdef HAVE_BKTR
		if (lt->reentrancy) {
			ast_reentrancy_lock(lt);
			bt = &lt->backtrace[lt->reentrancy-1];
			ast_reentrancy_unlock(lt);
		} else {
			bt = NULL;
		}
		if (t->tracking) {
			ast_remove_lock_info(t, bt);
		}
#else
		if (t->tracking) {
			ast_remove_lock_info(t);
		}
#endif
	}
	if (res) {
		__ast_mutex_logger("%s line %d (%s): Error obtaining read lock: %s\n",
				filename, line, func, strerror(res));
		DO_THREAD_CRASH;
	}
#endif /* DEBUG_THREADS */

	return res;
}
Esempio n. 7
0
int __ast_rwlock_wrlock(const char *filename, int line, const char *func, ast_rwlock_t *t, const char *name)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt = NULL;
	int canlog = t->tracking && strcmp(filename, "logger.c");
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

	if (t->tracking) {
		lt = ast_get_reentrancy(&t->track);
	}

	if (lt) {
#ifdef HAVE_BKTR
		struct ast_bt tmp;

		/* The implementation of backtrace() may have its own locks.
		 * Capture the backtrace outside of the reentrancy lock to
		 * avoid deadlocks. See ASTERISK-22455. */
		ast_bt_get_addresses(&tmp);

		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->backtrace[lt->reentrancy] = tmp;
			bt = &lt->backtrace[lt->reentrancy];
		}
		ast_reentrancy_unlock(lt);

		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t, bt);
#else
		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t);
#endif
	}
#endif /* DEBUG_THREADS */

#if defined(DETECT_DEADLOCKS) && defined(DEBUG_THREADS)
	{
		time_t seconds = time(NULL);
		time_t wait_time, reported_wait = 0;
		do {
			res = pthread_rwlock_trywrlock(&t->lock);
			if (res == EBUSY) {
				wait_time = time(NULL) - seconds;
				if (wait_time > reported_wait && (wait_time % 5) == 0) {
					__ast_mutex_logger("%s line %d (%s): Deadlock? waited %d sec for writelock '%s'?\n",
						filename, line, func, (int)wait_time, name);
					if (lt) {
						ast_reentrancy_lock(lt);
#ifdef HAVE_BKTR
						__dump_backtrace(&lt->backtrace[lt->reentrancy], canlog);
#endif
						__ast_mutex_logger("%s line %d (%s): '%s' was locked  here.\n",
								lt->file[lt->reentrancy-1], lt->lineno[lt->reentrancy-1],
								lt->func[lt->reentrancy-1], name);
#ifdef HAVE_BKTR
						__dump_backtrace(&lt->backtrace[lt->reentrancy-1], canlog);
#endif
						ast_reentrancy_unlock(lt);
					}
					reported_wait = wait_time;
				}
				usleep(200);
			}
		} while (res == EBUSY);
	}
#else /* !DETECT_DEADLOCKS || !DEBUG_THREADS */
	res = pthread_rwlock_wrlock(&t->lock);
#endif /* !DETECT_DEADLOCKS || !DEBUG_THREADS */

#ifdef DEBUG_THREADS
	if (!res && lt) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = line;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
			lt->reentrancy++;
		}
		ast_reentrancy_unlock(lt);
		ast_mark_lock_acquired(t);
	} else if (lt) {
#ifdef HAVE_BKTR
		if (lt->reentrancy) {
			ast_reentrancy_lock(lt);
			bt = &lt->backtrace[lt->reentrancy-1];
			ast_reentrancy_unlock(lt);
		} else {
			bt = NULL;
		}
		ast_remove_lock_info(t, bt);
#else
		ast_remove_lock_info(t);
#endif
	}
	if (res) {
		__ast_mutex_logger("%s line %d (%s): Error obtaining write lock: %s\n",
				filename, line, func, strerror(res));
		DO_THREAD_CRASH;
	}
#endif /* DEBUG_THREADS */

	return res;
}
Esempio n. 8
0
int __ast_pthread_mutex_trylock(const char *filename, int lineno, const char *func,
				const char* mutex_name, ast_mutex_t *t)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt = NULL;
	int canlog = t->tracking && strcmp(filename, "logger.c");
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

	if (t->tracking) {
		lt = ast_get_reentrancy(&t->track);
	}

	if (lt) {
#ifdef HAVE_BKTR
		struct ast_bt tmp;

		/* The implementation of backtrace() may have its own locks.
		 * Capture the backtrace outside of the reentrancy lock to
		 * avoid deadlocks. See ASTERISK-22455. */
		ast_bt_get_addresses(&tmp);

		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->backtrace[lt->reentrancy] = tmp;
			bt = &lt->backtrace[lt->reentrancy];
		}
		ast_reentrancy_unlock(lt);

		ast_store_lock_info(AST_MUTEX, filename, lineno, func, mutex_name, t, bt);
#else
		ast_store_lock_info(AST_MUTEX, filename, lineno, func, mutex_name, t);
#endif
	}
#endif /* DEBUG_THREADS */

	res = pthread_mutex_trylock(&t->mutex);

#ifdef DEBUG_THREADS
	if (lt && !res) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = lineno;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
			lt->reentrancy++;
		} else {
			__ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
					   filename, lineno, func, mutex_name);
		}
		ast_reentrancy_unlock(lt);
		ast_mark_lock_acquired(t);
	} else if (lt) {
		ast_mark_lock_failed(t);
	}
#endif /* DEBUG_THREADS */

	return res;
}
Esempio n. 9
0
int __ast_rwlock_timedwrlock(const char *filename, int line, const char *func, ast_rwlock_t *t, const char *name,
	const struct timespec *abs_timeout)
{
	int res;

#ifdef DEBUG_THREADS
	struct ast_lock_track *lt = NULL;
	int canlog = t->tracking && strcmp(filename, "logger.c");
#ifdef HAVE_BKTR
	struct ast_bt *bt = NULL;
#endif

	if (t->tracking) {
		lt = ast_get_reentrancy(&t->track);
	}

	if (lt) {
#ifdef HAVE_BKTR
		struct ast_bt tmp;

		/* The implementation of backtrace() may have its own locks.
		 * Capture the backtrace outside of the reentrancy lock to
		 * avoid deadlocks. See ASTERISK-22455. */
		ast_bt_get_addresses(&tmp);

		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->backtrace[lt->reentrancy] = tmp;
			bt = &lt->backtrace[lt->reentrancy];
		}
		ast_reentrancy_unlock(lt);

		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t, bt);
#else
		ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t);
#endif
	}
#endif /* DEBUG_THREADS */

#ifdef HAVE_PTHREAD_RWLOCK_TIMEDWRLOCK
	res = pthread_rwlock_timedwrlock(&t->lock, abs_timeout);
#else
	do {
		struct timeval _now;
		for (;;) {
			if (!(res = pthread_rwlock_trywrlock(&t->lock))) {
				break;
			}
			_now = ast_tvnow();
			if (_now.tv_sec > abs_timeout->tv_sec || (_now.tv_sec == abs_timeout->tv_sec && _now.tv_usec * 1000 > abs_timeout->tv_nsec)) {
				break;
			}
			usleep(1);
		}
	} while (0);
#endif

#ifdef DEBUG_THREADS
	if (!res && lt) {
		ast_reentrancy_lock(lt);
		if (lt->reentrancy < AST_MAX_REENTRANCY) {
			lt->file[lt->reentrancy] = filename;
			lt->lineno[lt->reentrancy] = line;
			lt->func[lt->reentrancy] = func;
			lt->thread[lt->reentrancy] = pthread_self();
			lt->reentrancy++;
		}
		ast_reentrancy_unlock(lt);
		ast_mark_lock_acquired(t);
	} else if (lt) {
#ifdef HAVE_BKTR
		if (lt->reentrancy) {
			ast_reentrancy_lock(lt);
			bt = &lt->backtrace[lt->reentrancy-1];
			ast_reentrancy_unlock(lt);
		} else {
			bt = NULL;
		}
		ast_remove_lock_info(t, bt);
#else
		ast_remove_lock_info(t);
#endif
	}
	if (res) {
		__ast_mutex_logger("%s line %d (%s): Error obtaining read lock: %s\n",
				filename, line, func, strerror(res));
		DO_THREAD_CRASH;
	}
#endif /* DEBUG_THREADS */

	return res;
}