if (group_dead)
kill_orphaned_pgrp(tsk->group_leader, NULL);
- /* Let father know we died
- *
- * Thread signals are configurable, but you aren't going to use
- * that to send signals to arbitrary processes.
- * That stops right now.
- *
- * If the parent exec id doesn't match the exec id we saved
- * when we started then we know the parent has changed security
- * domain.
- *
- * If our self_exec id doesn't match our parent_exec_id then
- * we have changed execution domain as these two values started
- * the same after a fork.
- */
- if (thread_group_leader(tsk) && tsk->exit_signal != SIGCHLD &&
- (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
- tsk->self_exec_id != tsk->parent_exec_id))
- tsk->exit_signal = SIGCHLD;
-
if (unlikely(tsk->ptrace)) {
int sig = thread_group_leader(tsk) &&
thread_group_empty(tsk) &&
preempt_disable();
exit_rcu();
+
+ /*
+ * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
+ * when the following two conditions become true.
+ * - There is race condition of mmap_sem (It is acquired by
+ * exit_mm()), and
+ * - SMI occurs before setting TASK_RUNINNG.
+ * (or hypervisor of virtual machine switches to other guest)
+ * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
+ *
+ * To avoid it, we have to wait for releasing tsk->pi_lock which
+ * is held by try_to_wake_up()
+ */
+ smp_mb();
+ raw_spin_unlock_wait(&tsk->pi_lock);
+
/* causes final put_task_struct in finish_task_switch(). */
tsk->state = TASK_DEAD;
schedule();
}
/* dead body doesn't have much to contribute */
- if (p->exit_state == EXIT_DEAD)
+ if (unlikely(p->exit_state == EXIT_DEAD)) {
+ /*
+ * But do not ignore this task until the tracer does
+ * wait_task_zombie()->do_notify_parent().
+ */
+ if (likely(!ptrace) && unlikely(ptrace_reparented(p)))
+ wo->notask_error = 0;
return 0;
+ }
/* slay zombie? */
if (p->exit_state == EXIT_ZOMBIE) {