Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754308Ab3GXOeY (ORCPT ); Wed, 24 Jul 2013 10:34:24 -0400 Received: from mga01.intel.com ([192.55.52.88]:31327 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753696Ab3GXOdi (ORCPT ); Wed, 24 Jul 2013 10:33:38 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,735,1367996400"; d="scan'208";a="375285837" Message-ID: <51EFE5A8.1060109@linux.intel.com> Date: Wed, 24 Jul 2013 07:33:12 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, jkosina@suse.cz, masami.hiramatsu.pt@hitachi.com, rostedt@goodmis.org, tglx@linutronix.de, hpa@linux.intel.com, fengguang.wu@intel.com CC: tip-bot for Jiri Kosina , linux-tip-commits@vger.kernel.org Subject: Re: [tip:perf/core] kprobes/x86: Call out into INT3 handler directly instead of using notifier References: In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1307 Lines: 32 On 07/23/2013 08:55 PM, tip-bot for Jiri Kosina wrote: > Commit-ID: 17f41571bb2c4a398785452ac2718a6c5d77180e > Gitweb: http://git.kernel.org/tip/17f41571bb2c4a398785452ac2718a6c5d77180e > Author: Jiri Kosina > AuthorDate: Tue, 23 Jul 2013 10:09:28 +0200 > Committer: Ingo Molnar > CommitDate: Tue, 23 Jul 2013 10:12:57 +0200 > > kprobes/x86: Call out into INT3 handler directly instead of using notifier > > In fd4363fff3d96 ("x86: Introduce int3 (breakpoint)-based > instruction patching"), the mechanism that was introduced for > notifying alternatives code from int3 exception handler that and > exception occured was die_notifier. > > This is however problematic, as early code might be using jump > labels even before the notifier registration has been performed, > which will then lead to an oops due to unhandled exception. One > of such occurences has been encountered by Fengguang: > Please note that putting this patch in perf/core means x86/jumplabel is completely nonfunctional by itself. -hpa -- 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/