Merge tag 'pwm/for-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry...

[sfrench/cifs-2.6.git] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index 7d4a9a6df95688027da8236897225f95c7894889..b07adca97ea3d31f5568c97a3580fbf2f3dd178f 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2063,6 +2063,24 @@ static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
 }
 #endif
 
+static int propagate_has_child_subreaper(struct task_struct *p, void *data)
+{
+       /*
+        * If task has has_child_subreaper - all its decendants
+        * already have these flag too and new decendants will
+        * inherit it on fork, skip them.
+        *
+        * If we've found child_reaper - skip descendants in
+        * it's subtree as they will never get out pidns.
+        */
+       if (p->signal->has_child_subreaper ||
+           is_child_reaper(task_pid(p)))
+               return 0;
+
+       p->signal->has_child_subreaper = 1;
+       return 1;
+}
+
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                unsigned long, arg4, unsigned long, arg5)
 {
@@ -2214,6 +2232,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
                break;
        case PR_SET_CHILD_SUBREAPER:
                me->signal->is_child_subreaper = !!arg2;
+               if (!arg2)
+                       break;
+
+               walk_process_tree(me, propagate_has_child_subreaper, NULL);
                break;
        case PR_GET_CHILD_SUBREAPER:
                error = put_user(me->signal->is_child_subreaper,