From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932258Ab1LENR5 (ORCPT ); Mon, 5 Dec 2011 08:17:57 -0500 Received: from terminus.zytor.com ([198.137.202.10]:57367 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932124Ab1LENR4 (ORCPT ); Mon, 5 Dec 2011 08:17:56 -0500 Date: Mon, 5 Dec 2011 05:17:34 -0800 From: tip-bot for Mitsuo Hayasaka Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, rdunlap@xenotime.net, tglx@linutronix.de, mingo@elte.hu, mitsuo.hayasaka.hu@hitachi.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, rdunlap@xenotime.net, mitsuo.hayasaka.hu@hitachi.com, mingo@elte.hu In-Reply-To: <20111129060821.11076.55315.stgit@ltc219.sdl.hitachi.co.jp> References: <20111129060821.11076.55315.stgit@ltc219.sdl.hitachi.co.jp> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/debug] x86: Add user_mode_vm check in stack_overflow_check Git-Commit-ID: 69682b625a043b567873e6cda397969b502f0054 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Mon, 05 Dec 2011 05:17:40 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 69682b625a043b567873e6cda397969b502f0054 Gitweb: http://git.kernel.org/tip/69682b625a043b567873e6cda397969b502f0054 Author: Mitsuo Hayasaka AuthorDate: Tue, 29 Nov 2011 15:08:21 +0900 Committer: Ingo Molnar CommitDate: Mon, 5 Dec 2011 11:28:25 +0100 x86: Add user_mode_vm check in stack_overflow_check The kernel stack overflow is checked in stack_overflow_check(), which may wrongly detect the overflow if the stack pointer in user space points to the kernel stack intentionally or accidentally. So, the actual overflow is never detected after this misdetection because WARN_ONCE() is used on the detection of it. This patch adds user-mode-vm checking before it to avoid this problem and bails out early if the user stack is used. Signed-off-by: Mitsuo Hayasaka Cc: yrl.pp-manager.tt@hitachi.com Cc: Randy Dunlap Link: http://lkml.kernel.org/r/20111129060821.11076.55315.stgit@ltc219.sdl.hitachi.co.jp Signed-off-by: Ingo Molnar Cc: "H. Peter Anvin" --- arch/x86/kernel/irq_64.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c index acf8fbf..69bca46 100644 --- a/arch/x86/kernel/irq_64.c +++ b/arch/x86/kernel/irq_64.c @@ -38,6 +38,9 @@ static inline void stack_overflow_check(struct pt_regs *regs) #ifdef CONFIG_DEBUG_STACKOVERFLOW u64 curbase = (u64)task_stack_page(current); + if (user_mode_vm(regs)) + return; + WARN_ONCE(regs->sp >= curbase && regs->sp <= curbase + THREAD_SIZE && regs->sp < curbase + sizeof(struct thread_info) +