From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04ED9C33CB1 for ; Tue, 14 Jan 2020 13:04:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA2A624685 for ; Tue, 14 Jan 2020 13:04:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729639AbgANNEl (ORCPT ); Tue, 14 Jan 2020 08:04:41 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:43125 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728748AbgANNCV (ORCPT ); Tue, 14 Jan 2020 08:02:21 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1irLpq-0004bc-EM; Tue, 14 Jan 2020 14:02:18 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 12E111C07F3; Tue, 14 Jan 2020 14:02:15 +0100 (CET) Date: Tue, 14 Jan 2020 13:02:14 -0000 From: "tip-bot2 for Dmitry Safonov" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: timers/core] x86/vdso: Zap vvar pages when switching to a time namespace Cc: Andrei Vagin , Dmitry Safonov , Thomas Gleixner , x86 , LKML In-Reply-To: <20191112012724.250792-27-dima@arista.com> References: <20191112012724.250792-27-dima@arista.com> MIME-Version: 1.0 Message-ID: <157900693486.396.13799366172237092744.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the timers/core branch of tip: Commit-ID: 70ddf65184ec1e8989322f35193e4fde7377f0cc Gitweb: https://git.kernel.org/tip/70ddf65184ec1e8989322f35193e4fde7377f0cc Author: Dmitry Safonov AuthorDate: Tue, 12 Nov 2019 01:27:15 Committer: Thomas Gleixner CommitterDate: Tue, 14 Jan 2020 12:20:59 +01:00 x86/vdso: Zap vvar pages when switching to a time namespace The VVAR page layout depends on whether a task belongs to the root or non-root time namespace. Whenever a task changes its namespace, the VVAR page tables are cleared and then they will be re-faulted with a corresponding layout. Co-developed-by: Andrei Vagin Signed-off-by: Andrei Vagin Signed-off-by: Dmitry Safonov Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20191112012724.250792-27-dima@arista.com --- arch/x86/entry/vdso/vma.c | 27 +++++++++++++++++++++++++++ include/linux/time_namespace.h | 9 +++++++++ kernel/time/namespace.c | 10 ++++++++++ 3 files changed, 46 insertions(+) diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index d2fd8a5..c1b8496 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -51,6 +51,7 @@ void __init init_vdso_image(const struct vdso_image *image) image->alt_len)); } +static const struct vm_special_mapping vvar_mapping; struct linux_binprm; static vm_fault_t vdso_fault(const struct vm_special_mapping *sm, @@ -128,6 +129,32 @@ static struct page *find_timens_vvar_page(struct vm_area_struct *vma) return NULL; } + +/* + * The vvar page layout depends on whether a task belongs to the root or + * non-root time namespace. Whenever a task changes its namespace, the VVAR + * page tables are cleared and then they will re-faulted with a + * corresponding layout. + * See also the comment near timens_setup_vdso_data() for details. + */ +int vdso_join_timens(struct task_struct *task, struct time_namespace *ns) +{ + struct mm_struct *mm = task->mm; + struct vm_area_struct *vma; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + unsigned long size = vma->vm_end - vma->vm_start; + + if (vma_is_special_mapping(vma, &vvar_mapping)) + zap_page_range(vma, vma->vm_start, size); + } + + up_write(&mm->mmap_sem); + return 0; +} #else static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma) { diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h index 6b7767f..04a2ba8 100644 --- a/include/linux/time_namespace.h +++ b/include/linux/time_namespace.h @@ -31,6 +31,9 @@ struct time_namespace { extern struct time_namespace init_time_ns; #ifdef CONFIG_TIME_NS +extern int vdso_join_timens(struct task_struct *task, + struct time_namespace *ns); + static inline struct time_namespace *get_time_ns(struct time_namespace *ns) { kref_get(&ns->kref); @@ -77,6 +80,12 @@ static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim) } #else +static inline int vdso_join_timens(struct task_struct *task, + struct time_namespace *ns) +{ + return 0; +} + static inline struct time_namespace *get_time_ns(struct time_namespace *ns) { return NULL; diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c index d705c15..0732964 100644 --- a/kernel/time/namespace.c +++ b/kernel/time/namespace.c @@ -281,6 +281,7 @@ static void timens_put(struct ns_common *ns) static int timens_install(struct nsproxy *nsproxy, struct ns_common *new) { struct time_namespace *ns = to_time_ns(new); + int err; if (!current_is_single_threaded()) return -EUSERS; @@ -291,6 +292,10 @@ static int timens_install(struct nsproxy *nsproxy, struct ns_common *new) timens_set_vvar_page(current, ns); + err = vdso_join_timens(current, ns); + if (err) + return err; + get_time_ns(ns); put_time_ns(nsproxy->time_ns); nsproxy->time_ns = ns; @@ -305,6 +310,7 @@ int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk) { struct ns_common *nsc = &nsproxy->time_ns_for_children->ns; struct time_namespace *ns = to_time_ns(nsc); + int err; /* create_new_namespaces() already incremented the ref counter */ if (nsproxy->time_ns == nsproxy->time_ns_for_children) @@ -312,6 +318,10 @@ int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk) timens_set_vvar_page(tsk, ns); + err = vdso_join_timens(tsk, ns); + if (err) + return err; + get_time_ns(ns); put_time_ns(nsproxy->time_ns); nsproxy->time_ns = ns;