Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753180AbaA1Gwn (ORCPT ); Tue, 28 Jan 2014 01:52:43 -0500 Received: from mga09.intel.com ([134.134.136.24]:54949 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750816AbaA1Gwm (ORCPT ); Tue, 28 Jan 2014 01:52:42 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.95,734,1384329600"; d="scan'208";a="445649524" Message-ID: <52E75261.5030307@intel.com> Date: Tue, 28 Jan 2014 14:46:57 +0800 From: Ren Qiaowei User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 To: Andy Lutomirski CC: "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , X86 ML , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v3 2/4] x86, mpx: hook #BR exception handler to allocate bound tables References: <1390727338-20487-1-git-send-email-qiaowei.ren@intel.com> <1390727338-20487-3-git-send-email-qiaowei.ren@intel.com> <52E6C33C.8050706@amacapital.net> <52E72573.9090108@intel.com> <52E742A0.8000209@intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/28/2014 02:42 PM, Andy Lutomirski wrote: > I just read it. do_trap_no_signal presumably calls fixup_exception > because #UD uses it and #UD needs that handling. (I'm guessing that > there is actually a legitimate use for a kernel fixup on #UD somewhere > -- there's probably something that isn't covered by cpuid.) > > There should not be a #BR from the kernel using the fixup mechanism. > IMO if the exception comes from the kernel, it should unconditionally > call die. > Oh. I agree with you, and if a #BR from the kernel it should unconditionally call die. if (!user_mode(regs)) die("bounds", regs, error_code); Thanks, Qiaowei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/