From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756622Ab0CCU2V (ORCPT ); Wed, 3 Mar 2010 15:28:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50424 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752877Ab0CCU2G (ORCPT ); Wed, 3 Mar 2010 15:28:06 -0500 Date: Wed, 3 Mar 2010 21:26:50 +0100 From: Oleg Nesterov To: Andrew Morton Cc: Roland McGrath , wylda@volny.cz, gregkh@suse.de, jkosina@suse.cz, Linus Torvalds , Sukadev Bhattiprolu , Serge Hallyn , linux-kernel@vger.kernel.org Subject: [PATCH] pid_ns: zap_pid_ns_processes: use SEND_SIG_NOINFO instead of force_sig() Message-ID: <20100303202650.GA15521@redhat.com> References: <20100302201646.GA10734@redhat.com> <20100303013227.4FFDE89EB@magilla.sf.frob.com> <20100303112343.B89802F@magilla.sf.frob.com> <20100303184412.GA7816@redhat.com> <20100303193003.GA10734@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100303193003.GA10734@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 zap_pid_ns_processes() uses force_sig(SIGKILL) to ensure SIGKILL will be delivered to sub-namespace inits as well. This is correct, but we are going to change force_sig_info() semantics. See http://bugzilla.kernel.org/show_bug.cgi?id=15395#c31 We can use send_sig_info(SEND_SIG_NOINFO) instead, since 614c517d7c00af1b26ded20646b329397d6f51a1 SEND_SIG_NOINFO means "from user" and therefore send_signal() will get the correct from_ancestor_ns = T flag. Signed-off-by: Oleg Nesterov --- kernel/pid_namespace.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- mm/kernel/pid_namespace.c~NS_DONT_ABUSE_FORCE 2010-02-25 15:22:13.000000000 +0100 +++ mm/kernel/pid_namespace.c 2010-03-03 20:58:12.000000000 +0100 @@ -161,13 +161,12 @@ void zap_pid_ns_processes(struct pid_nam rcu_read_lock(); /* - * Use force_sig() since it clears SIGNAL_UNKILLABLE ensuring - * any nested-container's init processes don't ignore the - * signal + * Any nested-container's init processes won't ignore the + * SEND_SIG_NOINFO signal, see send_signal()->si_fromuser(). */ task = pid_task(find_vpid(nr), PIDTYPE_PID); if (task) - force_sig(SIGKILL, task); + send_sig_info(SIGKILL, SEND_SIG_NOINFO, task); rcu_read_unlock();