Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754742AbbGFLiA (ORCPT ); Mon, 6 Jul 2015 07:38:00 -0400 Received: from mail4.hitachi.co.jp ([133.145.228.5]:34220 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752725AbbGFLh4 (ORCPT ); Mon, 6 Jul 2015 07:37:56 -0400 Message-ID: <559A688D.1040501@hitachi.com> Date: Mon, 06 Jul 2015 20:37:49 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Will Deacon , Pratyush Anand CC: "linux-arm-kernel@lists.infradead.org" , "linux@arm.linux.org.uk" , Catalin Marinas , "linux-kernel@vger.kernel.org" , "wcohen@redhat.com" , "dave.long@linaro.org" , "steve.capper@linaro.org" Subject: Re: [PATCH 1/2] arm64: Blacklist non-kprobe-able symbols References: <9994841a0b0a8194a6dcc1b6af148ba358488c62.1436158027.git.panand@redhat.com> <20150706090323.GB30342@arm.com> In-Reply-To: <20150706090323.GB30342@arm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1249 Lines: 32 On 2015/07/06 18:03, Will Deacon wrote: > On Mon, Jul 06, 2015 at 06:03:21AM +0100, Pratyush Anand wrote: >> Add all function symbols which are called from do_debug_exception under >> NOKPROBE_SYMBOL, as they can not kprobed. > > It's a shame this has to be so manual, but I suppose it's done on a > best-effort basis to catch broken probe placement. Ah, yes. You can use kprobe-tracer in ftrace by feeding all symbols to them and enabling it (and pray). > If we miss a function and somebody probes it, do we just get stuck in a > recursive exception, or could we print something suggesting that a symbol > be annotated as NOKPROBE? For some cases we can detect recursion, but usually, it may reset itself or infinite recursion loop before detecting it. :( Thank you, -- Masami HIRAMATSU Linux Technology Research Center, System Productivity Research Dept. Center for Technology Innovation - Systems Engineering Hitachi, Ltd., Research & Development Group E-mail: masami.hiramatsu.pt@hitachi.com -- 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/