From patchwork Thu Jul 30 12:00:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kirill Tkhai X-Patchwork-Id: 11692853 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6360F913 for ; Thu, 30 Jul 2020 12:00:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51B4020838 for ; Thu, 30 Jul 2020 12:00:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728272AbgG3MAd (ORCPT ); Thu, 30 Jul 2020 08:00:33 -0400 Received: from relay.sw.ru ([185.231.240.75]:56830 "EHLO relay3.sw.ru" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728005AbgG3MA1 (ORCPT ); Thu, 30 Jul 2020 08:00:27 -0400 Received: from [192.168.15.64] (helo=localhost.localdomain) by relay3.sw.ru with esmtp (Exim 4.93) (envelope-from ) id 1k17EI-0002y6-PL; Thu, 30 Jul 2020 15:00:10 +0300 Subject: [PATCH 12/23] user: Free user_ns one RCU grace period after final counter put From: Kirill Tkhai To: viro@zeniv.linux.org.uk, adobriyan@gmail.com, davem@davemloft.net, ebiederm@xmission.com, akpm@linux-foundation.org, christian.brauner@ubuntu.com, areber@redhat.com, serge@hallyn.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, ktkhai@virtuozzo.com Date: Thu, 30 Jul 2020 15:00:24 +0300 Message-ID: <159611042455.535980.12021168777274312453.stgit@localhost.localdomain> In-Reply-To: <159611007271.535980.15362304262237658692.stgit@localhost.localdomain> References: <159611007271.535980.15362304262237658692.stgit@localhost.localdomain> User-Agent: StGit/0.19 MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This is needed to link user_ns into ns_idr in next patch. Signed-off-by: Kirill Tkhai --- include/linux/user_namespace.h | 5 ++++- kernel/user_namespace.c | 9 ++++++++- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 64cf8ebdc4ec..58fede304201 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -79,7 +79,10 @@ struct user_namespace { #ifdef CONFIG_PERSISTENT_KEYRINGS struct key *persistent_keyring_register; #endif - struct work_struct work; + union { + struct work_struct work; + struct rcu_head rcu; + }; #ifdef CONFIG_SYSCTL struct ctl_table_set set; struct ctl_table_header *sysctls; diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 7c2bbe8f3e45..367a942bb484 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -171,6 +171,13 @@ int unshare_userns(unsigned long unshare_flags, struct cred **new_cred) return err; } +static void free_user_ns_rcu(struct rcu_head *head) +{ + struct user_namespace *ns = container_of(head, struct user_namespace, + rcu); + kmem_cache_free(user_ns_cachep, ns); +} + static void free_user_ns(struct work_struct *work) { struct user_namespace *parent, *ns = @@ -194,7 +201,7 @@ static void free_user_ns(struct work_struct *work) retire_userns_sysctls(ns); key_free_user_ns(ns); ns_free_inum(&ns->ns); - kmem_cache_free(user_ns_cachep, ns); + call_rcu(&ns->rcu, free_user_ns_rcu); dec_user_namespaces(ucounts); ns = parent; } while (refcount_dec_and_test(&parent->ns.count));