From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756003Ab3KMQF3 (ORCPT ); Wed, 13 Nov 2013 11:05:29 -0500 Received: from mail7.hitachi.co.jp ([133.145.228.42]:34059 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751254Ab3KMQF1 (ORCPT ); Wed, 13 Nov 2013 11:05:27 -0500 Message-ID: <5283A343.1000305@hitachi.com> Date: Thu, 14 Nov 2013 01:05:23 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Steven Rostedt Cc: Sandeepa Prabhu , Will Deacon , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "patches@linaro.org" , "linaro-kernel@lists.linaro.org" , Catalin Marinas , "steve.capper@linaro.org" , "nico@linaro.org" , "srikar@linux.vnet.ibm.com" , "dsaxena@linaro.org" , "Vijaya.Kumar@caviumnetworks.com" , Jiang Liu , "yrl.pp-manager.tt@hitachi.com" , Peter Zijlstra , Ingo Molnar Subject: Re: Re: [PATCH RFC 2/6] arm64: Kprobes with single stepping support References: <1382008671-4515-1-git-send-email-sandeepa.prabhu@linaro.org> <1382008671-4515-3-git-send-email-sandeepa.prabhu@linaro.org> <20131108165639.GD15074@mudshark.cambridge.arm.com> <527DFC1C.1020107@hitachi.com> <52808D53.7080904@hitachi.com> <5280B6C8.7050807@hitachi.com> <20131111105812.GC28302@mudshark.cambridge.arm.com> <528114C4.5000506@hitachi.com> <5281D848.7000502@hitachi.com> <52820043.6090107@hitachi.com> <20131112115935.23d05236@gandalf.local.home> In-Reply-To: <20131112115935.23d05236@gandalf.local.home> 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 (2013/11/13 1:59), Steven Rostedt wrote: > On Tue, 12 Nov 2013 16:25:26 +0530 > Sandeepa Prabhu wrote: > > >>> >>> BTW, I'm currently trying a general housecleaning of __kprobes >>> annotations. It may also have impact on your patch. >>> https://lkml.org/lkml/2013/11/8/187 >> Hmm, we can help testing your patchset on arm64 platforms. Also have >> many doubts on the changes you are working [blacklisting probes etc] >> >> Basically I had tried placing kprobe on memcpy() and the model hung >> (insmod never returned back!). Fast-model I have does not have option >> of any debug so no clue what happened!. >> memcpy() is low-level call being used internally within kprobes, so >> probably we cannot handle probe on that routine, but then how to make >> sure all such API are rejected by kprobe sub-system ? > > Working on ports of ftrace, I found that many of the functions in lib/ > are used by several locations that just can't be traced, due to how > low level they are. I just simply blacklisted the entire lib/ > directory (See the top of lib/Makefile) > > I wonder if there's an easy way to blacklist entire directories from > being used by kprobes too. Or at least do it by a file per file basis. Hm, perhaps we can do some magic in post-build script as kallsyms does. 1) make an object file 2) extract symbols from the file 3) put the symbols into data section as a list of strings 4) analyze the list at boot (init) time by using kallsyms how about this? :) Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com