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-rw-r--r--kernel/exit.c14
-rw-r--r--kernel/pid_namespace.c20
2 files changed, 33 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index c0277d3..a85efd2 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -64,7 +64,6 @@ static void exit_mm(struct task_struct * tsk);
static void __unhash_process(struct task_struct *p, bool group_dead)
{
nr_threads--;
- detach_pid(p, PIDTYPE_PID);
if (group_dead) {
detach_pid(p, PIDTYPE_PGID);
detach_pid(p, PIDTYPE_SID);
@@ -72,7 +71,20 @@ static void __unhash_process(struct task_struct *p, bool group_dead)
list_del_rcu(&p->tasks);
list_del_init(&p->sibling);
__this_cpu_dec(process_counts);
+ /*
+ * If we are the last child process in a pid namespace to be
+ * reaped, notify the reaper sleeping zap_pid_ns_processes().
+ */
+ if (IS_ENABLED(CONFIG_PID_NS)) {
+ struct task_struct *parent = p->real_parent;
+
+ if ((task_active_pid_ns(p)->child_reaper == parent) &&
+ list_empty(&parent->children) &&
+ (parent->flags & PF_EXITING))
+ wake_up_process(parent);
+ }
}
+ detach_pid(p, PIDTYPE_PID);
list_del_rcu(&p->thread_group);
}
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 16b20e3..b3c7fd5 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -184,11 +184,31 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
}
read_unlock(&tasklist_lock);
+ /* Firstly reap the EXIT_ZOMBIE children we may have. */
do {
clear_thread_flag(TIF_SIGPENDING);
rc = sys_wait4(-1, NULL, __WALL, NULL);
} while (rc != -ECHILD);
+ /*
+ * sys_wait4() above can't reap the TASK_DEAD children.
+ * Make sure they all go away, see __unhash_process().
+ */
+ for (;;) {
+ bool need_wait = false;
+
+ read_lock(&tasklist_lock);
+ if (!list_empty(&current->children)) {
+ __set_current_state(TASK_UNINTERRUPTIBLE);
+ need_wait = true;
+ }
+ read_unlock(&tasklist_lock);
+
+ if (!need_wait)
+ break;
+ schedule();
+ }
+
if (pid_ns->reboot)
current->signal->group_exit_code = pid_ns->reboot;
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