pid namespaces: rework forget_original_parent()

[firefly-linux-kernel-4.4.55.git] / kernel / exit.c

diff --git a/kernel/exit.c b/kernel/exit.c
index 179ac74bf9115c4f6889b1b03b4ee3fdfc96482a..3f2182ccf1875818c22ddc9395591769413fb54c 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -666,10 +666,14 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
  * the child reaper process (ie "init") in our pid
  * space.
  */
-static void
-forget_original_parent(struct task_struct *father, struct list_head *to_release)
+static void forget_original_parent(struct task_struct *father)
 {
        struct task_struct *p, *n, *reaper = father;
+       struct list_head ptrace_dead;
+
+       INIT_LIST_HEAD(&ptrace_dead);
+
+       write_lock_irq(&tasklist_lock);
 
        do {
                reaper = next_thread(reaper);
@@ -677,7 +681,7 @@ forget_original_parent(struct task_struct *father, struct list_head *to_release)
                        reaper = task_child_reaper(father);
                        break;
                }
-       } while (reaper->exit_state);
+       } while (reaper->flags & PF_EXITING);
 
        /*
         * There are only two places where our children can be:
@@ -714,12 +718,23 @@ forget_original_parent(struct task_struct *father, struct list_head *to_release)
                 * while it was being traced by us, to be able to see it in wait4.
                 */
                if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
-                       list_add(&p->ptrace_list, to_release);
+                       list_add(&p->ptrace_list, &ptrace_dead);
        }
+
        list_for_each_entry_safe(p, n, &father->ptrace_children, ptrace_list) {
                p->real_parent = reaper;
                reparent_thread(p, father, 1);
        }
+
+       write_unlock_irq(&tasklist_lock);
+       BUG_ON(!list_empty(&father->children));
+       BUG_ON(!list_empty(&father->ptrace_children));
+
+       list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_list) {
+               list_del_init(&p->ptrace_list);
+               release_task(p);
+       }
+
 }
 
 /*
@@ -730,7 +745,6 @@ static void exit_notify(struct task_struct *tsk)
 {
        int state;
        struct task_struct *t;
-       struct list_head ptrace_dead, *_p, *_n;
        struct pid *pgrp;
 
        if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
@@ -751,8 +765,6 @@ static void exit_notify(struct task_struct *tsk)
                spin_unlock_irq(&tsk->sighand->siglock);
        }
 
-       write_lock_irq(&tasklist_lock);
-
        /*
         * This does two things:
         *
@@ -761,12 +773,9 @@ static void exit_notify(struct task_struct *tsk)
         *      as a result of our exiting, and if they have any stopped
         *      jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
         */
+       forget_original_parent(tsk);
 
-       INIT_LIST_HEAD(&ptrace_dead);
-       forget_original_parent(tsk, &ptrace_dead);
-       BUG_ON(!list_empty(&tsk->children));
-       BUG_ON(!list_empty(&tsk->ptrace_children));
-
+       write_lock_irq(&tasklist_lock);
        /*
         * Check to see if any process groups have become orphaned
         * as a result of our exiting, and if they have any stopped
@@ -831,12 +840,6 @@ static void exit_notify(struct task_struct *tsk)
 
        write_unlock_irq(&tasklist_lock);
 
-       list_for_each_safe(_p, _n, &ptrace_dead) {
-               list_del_init(_p);
-               t = list_entry(_p, struct task_struct, ptrace_list);
-               release_task(t);
-       }
-
        /* If the process is dead, release it - nobody will wait for it */
        if (state == EXIT_DEAD)
                release_task(tsk);