Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753962AbbBZPOX (ORCPT ); Thu, 26 Feb 2015 10:14:23 -0500 Received: from mail-lb0-f179.google.com ([209.85.217.179]:33530 "EHLO mail-lb0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753423AbbBZPOV (ORCPT ); Thu, 26 Feb 2015 10:14:21 -0500 MIME-Version: 1.0 In-Reply-To: <1424931315-44482-1-git-send-email-wangnan0@huawei.com> References: <1424931315-44482-1-git-send-email-wangnan0@huawei.com> From: Andy Lutomirski Date: Thu, 26 Feb 2015 07:14:00 -0800 Message-ID: Subject: Re: [PATCH] x86, traps: install gates using IST after cpu_init(). To: Wang Nan Cc: Masami Hiramatsu , Steven Rostedt , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , X86 ML , Oleg Nesterov , Dave Hansen , "linux-kernel@vger.kernel.org" , Li Zefan Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1042 Lines: 26 On Wed, Feb 25, 2015 at 10:15 PM, Wang Nan wrote: > X86_TRAP_NMI, X86_TRAP_DF and X86_TRAP_MC use their own stack. Those > stacks are invalid until cpu_init() installs TSS. > > This patch moves setting of the 3 gates after cpu_init(). > > Signed-off-by: Wang Nan > --- > > If I understand correctly, logically speaking the original code is > incorrect. However, there is no real bug caused by it for serval years. > I'm not sure whether this fix is practical or not. Fix them only for > logical correctness. Acked-by: Andy Lutomirski That being said, I'm pretty sure you're not fixing a bug here. Delivery of an exception with no handler is every bit as fatal as delivery of an exception with a non-working IST handler. --Andy -- 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/