From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16539 invoked by alias); 22 Nov 2013 11:46:28 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 16528 invoked by uid 89); 22 Nov 2013 11:46:28 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=0.6 required=5.0 tests=AWL,BAYES_50,RDNS_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no version=3.3.2 X-HELO: mail7.hitachi.co.jp Received: from Unknown (HELO mail7.hitachi.co.jp) (133.145.228.42) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 22 Nov 2013 11:46:26 +0000 Received: from mlsv3.hitachi.co.jp (unknown [133.144.234.166]) by mail7.hitachi.co.jp (Postfix) with ESMTP id DE0AE37AC6; Fri, 22 Nov 2013 20:46:18 +0900 (JST) Received: from mfilter06.hitachi.co.jp by mlsv3.hitachi.co.jp (8.13.1/8.13.1) id rAMBkIZd021731; Fri, 22 Nov 2013 20:46:18 +0900 Received: from vshuts02.hitachi.co.jp (vshuts02.hitachi.co.jp [10.201.6.84]) by mfilter06.hitachi.co.jp (Switch-3.3.4/Switch-3.3.4) with ESMTP id rAMBkHeY003659; Fri, 22 Nov 2013 20:46:18 +0900 Received: from gmml27.itg.hitachi.co.jp (unknown [158.213.165.130]) by vshuts02.hitachi.co.jp (Postfix) with ESMTP id 3AE91490041; Fri, 22 Nov 2013 20:46:17 +0900 (JST) Received: from [10.198.208.126] by gmml27.itg.hitachi.co.jp (AIX5.2/8.11.6p2/8.11.0) id rAMBkG66836364; Fri, 22 Nov 2013 20:46:16 +0900 Message-ID: <528F4406.3090309@hitachi.com> Date: Fri, 22 Nov 2013 11:46:00 -0000 From: Masami Hiramatsu User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Ingo Molnar Cc: "Frank Ch. Eigler" , linux-arch@vger.kernel.org, Ananth N Mavinakayanahalli , Sandeepa Prabhu , x86@kernel.org, lkml , "Steven Rostedt (Red Hat)" , virtualization@lists.linux-foundation.org, systemtap@sourceware.org, "David S. Miller" Subject: Re: Re: Re: [PATCH -tip v3 00/23] kprobes: introduce NOKPROBE_SYMBOL() and general cleaning of kprobe blacklist References: <20131120042148.15296.88360.stgit@kbuild-fedora.novalocal> <20131120153801.GA9743@gmail.com> <20131120173600.GK8993@redhat.com> <528D6C9F.8050809@hitachi.com> <20131121072938.GA16912@gmail.com> <528EC2FF.30301@hitachi.com> In-Reply-To: <528EC2FF.30301@hitachi.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2013-q4/txt/msg00264.txt.bz2 (2013/11/22 11:35), Masami Hiramatsu wrote: > (2013/11/21 16:29), Ingo Molnar wrote: >> >> * Masami Hiramatsu wrote: >> >>> (2013/11/21 2:36), Frank Ch. Eigler wrote: >> >> [ ... ] >>>> one needs to resort to something like: >>>> >>>> # cat /proc/kallsyms | grep ' [tT] ' | while read addr type symbol; do >>>> perf probe $symbol >>>> done >>>> >>>> then wait for a few hours for that to finish. Then, or while the loop >>>> is still running, run >>>> >>>> # perf record -e 'probe:*' -aR sleep 1 >>>> >>>> to take a kernel down. >>> >>> Um, indeed, current blacklist is not perfect. [...] >> >> Then it needs to be fixed ASAP! > > OK, I see. At least the two patches included this series > should be fixed. :) > > And more, I need to test all symbols and drills down. OK, what I've found was; - The functions which can be ftraced look good. (see tracing/available_filter_functions) - following functions should not be able to be probed. - memcpy, memset - native_load_sp0 and some other native functions (need to be clear) - restore - trace_graph_return - trace_hardirqs_off_thunk, trace_hardirqs_on_thunk - This list still be not perfect. I just enabled/disabled kprobes one by one. There might be combined bugs (combination of several kprobes). - Some of them are hard to specify by NOKPROBE_SYMBOL because they are defined in assembly file. Anyway, to fix all of them, I think we need file-based blacklist especially for assembler symbols. For example, we can get all text symbols by below command; nm some-file.o | grep -i " t " | cut -f3 -d" " so that we can make a blacklisted-symbol list for the file. I need to look the Kbuild for how I can do that in Makefile. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com