Commit 123be07b authored Sep 23, 2009 by Sukadev Bhattiprolu Committed by Linus Torvalds Sep 24, 2009

fork(): disable CLONE_PARENT for init



When global or container-init processes use CLONE_PARENT, they create a
multi-rooted process tree.  Besides siblings of global init remain as
zombies on exit since they are not reaped by their parent (swapper).  So
prevent global and container-inits from creating siblings.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Oren Laadan <orenl@cs.columbia.edu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 8d65af78

kernel/fork.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -979,6 +979,16 @@ static struct task_struct *copy_process(unsigned long clone_flags,
		if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
		return ERR_PTR(-EINVAL);

		/*
		* Siblings of global init remain as zombies on exit since they are
		* not reaped by their parent (swapper). To solve this and to avoid
		* multi-rooted process trees, prevent global and container-inits
		* from creating siblings.
		*/
		if ((clone_flags & CLONE_PARENT) &&
		current->signal->flags & SIGNAL_UNKILLABLE)
		return ERR_PTR(-EINVAL);

		retval = security_task_create(clone_flags);
		if (retval)
		goto fork_out;