/* Access to target the exiting thread with syscalls that use
* its kernel tid is controlled by killlock. For detached threads,
* any use past this point would have undefined behavior, but for
- * joinable threads it's a valid usage that must be handled. */
+ * joinable threads it's a valid usage that must be handled.
+ * Signals must be blocked since pthread_kill must be AS-safe. */
+ __block_app_sigs(&set);
LOCK(self->killlock);
- /* The thread list lock must be AS-safe, and thus requires
- * application signals to be blocked before it can be taken. */
- __block_app_sigs(&set);
+ /* The thread list lock must be AS-safe, and thus depends on
+ * application signals being blocked above. */
__tl_lock();
/* If this is the only thread in the list, don't proceed with
* signal state to prepare for exit to call atexit handlers. */
if (self->next == self) {
__tl_unlock();
- __restore_sigs(&set);
UNLOCK(self->killlock);
+ __restore_sigs(&set);
exit(0);
}
- /* At this point we are committed to thread termination. Unlink
- * the thread from the list. This change will not be visible
- * until the lock is released, which only happens after SYS_exit
- * has been called, via the exit futex address pointing at the lock. */
- libc.threads_minus_1--;
- self->next->prev = self->prev;
- self->prev->next = self->next;
- self->prev = self->next = self;
+ /* At this point we are committed to thread termination. */
/* Process robust list in userspace to handle non-pshared mutexes
* and the detached thread case where the robust list head will
__do_orphaned_stdio_locks();
__dl_thread_cleanup();
+ /* Last, unlink thread from the list. This change will not be visible
+ * until the lock is released, which only happens after SYS_exit
+ * has been called, via the exit futex address pointing at the lock.
+ * This needs to happen after any possible calls to LOCK() that might
+ * skip locking if process appears single-threaded. */
+ if (!--libc.threads_minus_1) libc.need_locks = -1;
+ self->next->prev = self->prev;
+ self->prev->next = self->next;
+ self->prev = self->next = self;
+
/* This atomic potentially competes with a concurrent pthread_detach
* call; the loser is responsible for freeing thread resources. */
int state = a_cas(&self->detach_state, DT_JOINABLE, DT_EXITING);
__wait(&args->control, 0, 2, 1);
if (args->control) {
__syscall(SYS_set_tid_address, &args->control);
- return 0;
+ for (;;) __syscall(SYS_exit, 0);
}
}
__syscall(SYS_rt_sigprocmask, SIG_SETMASK, &args->sig_mask, 0, _NSIG/8);
~(1UL<<((SIGCANCEL-1)%(8*sizeof(long))));
__tl_lock();
- libc.threads_minus_1++;
+ if (!libc.threads_minus_1++) libc.need_locks = 1;
ret = __clone((c11 ? start_c11 : start), stack, flags, args, &new->tid, TP_ADJ(new), &__thread_list_lock);
/* All clone failures translate to EAGAIN. If explicit scheduling
new->next->prev = new;
new->prev->next = new;
} else {
- libc.threads_minus_1--;
+ if (!--libc.threads_minus_1) libc.need_locks = 0;
}
__tl_unlock();
__restore_sigs(&set);