From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753113Ab2KPQgz (ORCPT ); Fri, 16 Nov 2012 11:36:55 -0500 Received: from out03.mta.xmission.com ([166.70.13.233]:33561 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753086Ab2KPQgw (ORCPT ); Fri, 16 Nov 2012 11:36:52 -0500 From: "Eric W. Biederman" To: Linux Containers Cc: , Oleg Nesterov , Serge Hallyn , Gao feng , Andrew Morton , "Eric W. Biederman" Date: Fri, 16 Nov 2012 08:35:45 -0800 Message-Id: <1353083750-3621-6-git-send-email-ebiederm@xmission.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1353083750-3621-1-git-send-email-ebiederm@xmission.com> References: <8739097bkk.fsf@xmission.com> <1353083750-3621-1-git-send-email-ebiederm@xmission.com> X-XM-AID: U2FsdGVkX18hapzv41FhTZje2x4V4HydR00/KnpVoiE= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -0.5 BAYES_05 BODY: Bayes spam probability is 1 to 5% * [score: 0.0137] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject * 0.0 T_TooManySym_02 5+ unique symbols in subject X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Linux Containers X-Spam-Relay-Country: Subject: [PATCH 06/11] pidns: Don't allow new processes in a dead pid namespace. X-SA-Exim-Version: 4.2.1 (built Sun, 08 Jan 2012 03:05:19 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Eric W. Biederman" Set nr_hashed to -1 just before we schedule the work to cleanup proc. Test nr_hashed just before we hash a new pid and if nr_hashed is < 0 fail. This guaranteees that processes never enter a pid namespaces after we have cleaned up the state to support processes in a pid namespace. Currently sending SIGKILL to all of the process in a pid namespace as init exists gives us this guarantee but we need something a little stronger to support unsharing and joining a pid namespace. Acked-by: "Serge E. Hallyn" Signed-off-by: Eric W. Biederman --- kernel/pid.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/kernel/pid.c b/kernel/pid.c index e957f8b..9c21911 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -274,8 +274,10 @@ void free_pid(struct pid *pid) for (i = 0; i <= pid->level; i++) { struct upid *upid = pid->numbers + i; hlist_del_rcu(&upid->pid_chain); - if (--upid->ns->nr_hashed == 0) + if (--upid->ns->nr_hashed == 0) { + upid->ns->nr_hashed = -1; schedule_work(&upid->ns->proc_work); + } } spin_unlock_irqrestore(&pidmap_lock, flags); @@ -321,6 +323,8 @@ struct pid *alloc_pid(struct pid_namespace *ns) upid = pid->numbers + ns->level; spin_lock_irq(&pidmap_lock); + if (ns->nr_hashed < 0) + goto out_unlock; for ( ; upid >= pid->numbers; --upid) { hlist_add_head_rcu(&upid->pid_chain, &pid_hash[pid_hashfn(upid->nr, upid->ns)]); @@ -331,6 +335,8 @@ struct pid *alloc_pid(struct pid_namespace *ns) out: return pid; +out_unlock: + spin_unlock(&pidmap_lock); out_free: while (++i <= ns->level) free_pidmap(pid->numbers + i); -- 1.7.5.4