* \brief General Asterisk locking.
*/
+/*** MODULEINFO
+ <support_level>core</support_level>
+ ***/
+
#include "asterisk.h"
ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+#include "asterisk/utils.h"
#include "asterisk/lock.h"
/* Allow direct use of pthread_mutex_* / pthread_cond_* */
#undef pthread_cond_wait
#undef pthread_cond_timedwait
+#if defined(DEBUG_THREADS) && defined(HAVE_BKTR)
+static void __dump_backtrace(struct ast_bt *bt, int canlog)
+{
+ char **strings;
+ ssize_t i;
+
+ strings = backtrace_symbols(bt->addresses, bt->num_frames);
+
+ for (i = 0; i < bt->num_frames; i++) {
+ __ast_mutex_logger("%s\n", strings[i]);
+ }
+
+ ast_std_free(strings);
+}
+#endif /* defined(DEBUG_THREADS) && defined(HAVE_BKTR) */
+
int __ast_pthread_mutex_init(int tracking, const char *filename, int lineno, const char *func,
const char *mutex_name, ast_mutex_t *t)
{
int res;
pthread_mutexattr_t attr;
- t->track = NULL;
#ifdef DEBUG_THREADS
+ t->track = NULL;
#if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) && defined(CAN_COMPARE_MUTEX_TO_INIT_VALUE)
if ((t->mutex) != ((pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER)) {
/*
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->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 /* DEBUG_THREADS */
+ ast_assert(res == 0);/*!< \todo BUGBUG Test to ensure that lock/unlock does not fail. */
return res;
}
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->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);
__ast_mutex_logger("%s line %d (%s): Error: mutex '%s' is uninitialized and unable to initialize.\n",
filename, lineno, func, mutex_name);
}
+ ast_assert(res == 0);/*!< \todo BUGBUG Test to ensure that lock/unlock does not fail. */
return res;
}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */
}
#endif /* DEBUG_THREADS */
+ ast_assert(res == 0);/*!< \todo BUGBUG Test to ensure that lock/unlock does not fail. */
return res;
}
#ifdef DEBUG_THREADS
struct ast_lock_track *lt;
+ struct ast_lock_track lt_orig;
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)) {
__dump_backtrace(<->backtrace[ROFFSET], canlog);
#endif
DO_THREAD_CRASH;
+ } else if (lt->reentrancy <= 0) {
+ __ast_mutex_logger("%s line %d (%s): attempted to wait on an unlocked mutex '%s'\n",
+ filename, lineno, func, mutex_name);
+ 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 = <->backtrace[lt->reentrancy - 1];
- }
-#endif
+ /* Waiting on a condition completely suspends a recursive mutex,
+ * even if it's been recursively locked multiple times. Make a
+ * copy of the lock tracking, and reset reentrancy to zero */
+ lt_orig = *lt;
+ lt->reentrancy = 0;
ast_reentrancy_unlock(lt);
-#ifdef HAVE_BKTR
- ast_remove_lock_info(t, bt);
-#else
- ast_remove_lock_info(t);
-#endif
+ ast_suspend_lock_info(t);
}
#endif /* DEBUG_THREADS */
filename, lineno, func, strerror(res));
DO_THREAD_CRASH;
} else if (t->tracking) {
+ pthread_mutex_t reentr_mutex_orig;
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(<->backtrace[lt->reentrancy]);
- bt = <->backtrace[lt->reentrancy];
-#endif
- lt->reentrancy++;
- } else {
- __ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
- filename, lineno, func, mutex_name);
- }
+ /* Restore lock tracking to what it was prior to the wait */
+ reentr_mutex_orig = lt->reentr_mutex;
+ *lt = lt_orig;
+ /* un-trash the mutex we just copied over */
+ lt->reentr_mutex = reentr_mutex_orig;
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
+ ast_restore_lock_info(t);
}
#endif /* DEBUG_THREADS */
#ifdef DEBUG_THREADS
struct ast_lock_track *lt;
+ struct ast_lock_track lt_orig;
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)) {
__dump_backtrace(<->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",
+ } else if (lt->reentrancy <= 0) {
+ __ast_mutex_logger("%s line %d (%s): attempted to wait on an unlocked mutex '%s'\n",
filename, lineno, func, mutex_name);
- lt->reentrancy = 0;
+ DO_THREAD_CRASH;
}
- 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 = <->backtrace[lt->reentrancy - 1];
- }
-#endif
+ /* Waiting on a condition completely suspends a recursive mutex,
+ * even if it's been recursively locked multiple times. Make a
+ * copy of the lock tracking, and reset reentrancy to zero */
+ lt_orig = *lt;
+ lt->reentrancy = 0;
ast_reentrancy_unlock(lt);
-#ifdef HAVE_BKTR
- ast_remove_lock_info(t, bt);
-#else
- ast_remove_lock_info(t);
-#endif
+ ast_suspend_lock_info(t);
}
#endif /* DEBUG_THREADS */
filename, lineno, func, strerror(res));
DO_THREAD_CRASH;
} else if (t->tracking) {
+ pthread_mutex_t reentr_mutex_orig;
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(<->backtrace[lt->reentrancy]);
- bt = <->backtrace[lt->reentrancy];
-#endif
- lt->reentrancy++;
- } else {
- __ast_mutex_logger("%s line %d (%s): '%s' really deep reentrancy!\n",
- filename, lineno, func, mutex_name);
- }
+ /* Restore lock tracking to what it was prior to the wait */
+ reentr_mutex_orig = lt->reentr_mutex;
+ *lt = lt_orig;
+ /* un-trash the mutex we just copied over */
+ lt->reentr_mutex = reentr_mutex_orig;
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
+ ast_suspend_lock_info(t);
}
#endif /* DEBUG_THREADS */
__ast_mutex_logger("%s line %d (%s): Error destroying rwlock %s: %s\n",
filename, lineno, func, rwlock_name, strerror(res));
}
- if (t->tracking) {
+ if (t->tracking && lt) {
ast_reentrancy_lock(lt);
lt->file[0] = filename;
lt->lineno[0] = lineno;
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->backtrace[lt->reentrancy];
}
ast_reentrancy_unlock(lt);
+
ast_store_lock_info(AST_RDLOCK, filename, line, func, name, t, bt);
#else
ast_store_lock_info(AST_RDLOCK, filename, line, func, name, t);
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->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);
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->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);
res = pthread_rwlock_timedrdlock(&t->lock, abs_timeout);
#else
do {
- struct timeval _start = ast_tvnow(), _diff;
+ struct timeval _now;
for (;;) {
if (!(res = pthread_rwlock_tryrdlock(&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)) {
+ _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);
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->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);
res = pthread_rwlock_timedwrlock(&t->lock, abs_timeout);
#else
do {
- struct timeval _start = ast_tvnow(), _diff;
+ struct timeval _now;
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)) {
+ _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);
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->backtrace[lt->reentrancy];
}
ast_reentrancy_unlock(lt);
+
ast_store_lock_info(AST_RDLOCK, filename, line, func, name, t, bt);
#else
ast_store_lock_info(AST_RDLOCK, filename, line, func, name, t);
if (t->tracking) {
#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) {
- ast_bt_get_addresses(<->backtrace[lt->reentrancy]);
+ lt->backtrace[lt->reentrancy] = tmp;
bt = <->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);
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