Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753414AbZGBMja (ORCPT ); Thu, 2 Jul 2009 08:39:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752043AbZGBMjX (ORCPT ); Thu, 2 Jul 2009 08:39:23 -0400 Received: from mx2.redhat.com ([66.187.237.31]:42693 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751370AbZGBMjX (ORCPT ); Thu, 2 Jul 2009 08:39:23 -0400 Date: Thu, 2 Jul 2009 14:36:26 +0200 From: Oleg Nesterov To: Sukadev Bhattiprolu Cc: Roland McGrath , "Eric W. Biederman" , Oren Laadan , serue@us.ibm.com, Alexey Dobriyan , Containers , linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] Disable CLONE_PARENT for init Message-ID: <20090702123626.GC3552@redhat.com> References: <20090701073140.GA14284@us.ibm.com> <20090701074654.A6C6321D57@magilla.sf.frob.com> <20090701082452.GA3297@redhat.com> <20090701214805.GA25734@us.ibm.com> <20090701215833.876DA404FD@magilla.sf.frob.com> <20090702003520.GA26247@us.ibm.com> <20090702075833.GA14620@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090702075833.GA14620@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1355 Lines: 37 On 07/02, Oleg Nesterov wrote: > > On 07/01, Sukadev Bhattiprolu wrote: > > > > --- linux-mmotm.orig/kernel/fork.c 2009-06-30 23:01:06.000000000 -0700 > > +++ linux-mmotm/kernel/fork.c 2009-07-01 17:29:09.000000000 -0700 > > @@ -974,6 +974,16 @@ static struct task_struct *copy_process( > > 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); > > Acked-by: Oleg Nesterov Thinking more, perhaps it makes sense to disallow CLONE_VM too. If init forks CLONE_VM task, this task can be killed by sig_kernel_coredump signal. In that case init will be killed too and the kernel will crash. But this is minor, we can trust the global init. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/