Allow signalling container-init

From: Sukadev Bhattiprolu <[email protected]>

Only the global-init process must be special - any other container-init process must be killable to prevent run-away processes in the system.

TODO: Ideally we should allow killing the container-init only from parent
container and prevent it being killed from within the container. But that is a more complex change and will be addressed by a follow-on patch. For now allow the container-init to be terminated by any process with sufficient privileges.

---

 signal.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

@@ -1861,11 +1861,9 @@ relock:
 			continue;
 
 		/*
-		 * Init of a pid space gets no signals it doesn't want from
-		 * within that pid space. It can of course get signals from
-		 * its parent pid space.
+		 * Global init gets no signals it doesn't want.
 		 */
-		if (current == task_child_reaper(current))
+		if (is_global_init(current))
 			continue;
 
 		if (sig_kernel_stop(signr)) {