From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756929AbYAPW1Q (ORCPT ); Wed, 16 Jan 2008 17:27:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753563AbYAPWPv (ORCPT ); Wed, 16 Jan 2008 17:15:51 -0500 Received: from mail.suse.de ([195.135.220.2]:55292 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754196AbYAPWPf (ORCPT ); Wed, 16 Jan 2008 17:15:35 -0500 From: Andi Kleen References: <200801161114.239449000@suse.de> In-Reply-To: <200801161114.239449000@suse.de> To: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, jbeulich@novell.com, venkatesh.pallipadi@intel.com Subject: [PATCH] [34/36] CPA: Add a BUG_ON checking for someone setting the kernel text NX Message-Id: <20080116221534.87A44150C8@wotan.suse.de> Date: Wed, 16 Jan 2008 23:15:34 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Someone setting NX on the kernel text tends to result in nasty failures and triple faults, so BUG_ON early for that. Does not cover __inittext. Signed-off-by: Andi Kleen Acked-by: Jan Beulich --- arch/x86/mm/pageattr_32.c | 8 ++++++++ 1 file changed, 8 insertions(+) Index: linux/arch/x86/mm/pageattr_32.c =================================================================== --- linux.orig/arch/x86/mm/pageattr_32.c +++ linux/arch/x86/mm/pageattr_32.c @@ -242,6 +242,14 @@ __change_page_attr(struct page *page, pg BUG_ON(PageLRU(kpte_page)); BUG_ON(PageCompound(kpte_page)); + /* + * Better fail early if someone sets the kernel text to NX. + * Does not cover __inittext + */ + BUG_ON(address >= (unsigned long)&_text && + address < (unsigned long)&_etext && + (pgprot_val(prot) & _PAGE_NX)); + set_tlb_flush(address, cache_attr_changed(*kpte, prot, level), level < 3);