From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753001Ab1K2GDP (ORCPT ); Tue, 29 Nov 2011 01:03:15 -0500 Received: from mail9.hitachi.co.jp ([133.145.228.44]:43486 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752416Ab1K2GDL (ORCPT ); Tue, 29 Nov 2011 01:03:11 -0500 X-AuditID: b753bd60-a2688ba000000655-f9-4ed4759da794 X-AuditID: b753bd60-a2688ba000000655-f9-4ed4759da794 From: Mitsuo Hayasaka Subject: [PATCH -v2 4/4] x86: cleanup the range of stack overflow checking To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Randy Dunlap Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, yrl.pp-manager.tt@hitachi.com, Mitsuo Hayasaka , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Date: Tue, 29 Nov 2011 15:08:45 +0900 Message-ID: <20111129060845.11076.40916.stgit@ltc219.sdl.hitachi.co.jp> In-Reply-To: <20111129060806.11076.74583.stgit@ltc219.sdl.hitachi.co.jp> References: <20111129060806.11076.74583.stgit@ltc219.sdl.hitachi.co.jp> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The overflow checking of kernel stack checks if the stack pointer points to the available kernel stack range, which is derived from the original overflow checking. It is clear that curbase address is always less than low boundary of available kernel stack. So, this patch removes the first condition that checks if the pointer is higher than curbase. Signed-off-by: Mitsuo Hayasaka Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" --- arch/x86/kernel/irq_64.c | 7 +++---- 1 files changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c index 5448bf6..c8c9a78 100644 --- a/arch/x86/kernel/irq_64.c +++ b/arch/x86/kernel/irq_64.c @@ -46,10 +46,9 @@ static inline void stack_overflow_check(struct pt_regs *regs) if (user_mode_vm(regs)) return; - if (regs->sp >= curbase && - regs->sp <= curbase + THREAD_SIZE && - regs->sp >= curbase + sizeof(struct thread_info) + - sizeof(struct pt_regs) + 128) + if (regs->sp >= curbase + sizeof(struct thread_info) + + sizeof(struct pt_regs) + 128 && + regs->sp <= curbase + THREAD_SIZE) return; irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack);