From: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Date: Fri, 19 Oct 2007 06:40:13 +0000 (-0700)
Subject: pid namespaces: allow signalling cgroup-init
X-Git-Tag: v2.6.24-rc1~210
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0fbc26a6cfab9f377e82e28225f2c0c6b4661e5c;p=linux-2.6

pid namespaces: allow signalling cgroup-init

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

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

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/signal.c b/kernel/signal.c
index 8214ffad54..98923882ba 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1835,11 +1835,9 @@ 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)) {