From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20357 invoked by alias); 20 Dec 2013 08:31:17 -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 20346 invoked by uid 89); 20 Dec 2013 08:31:16 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-qc0-f173.google.com Received: from mail-qc0-f173.google.com (HELO mail-qc0-f173.google.com) (209.85.216.173) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Fri, 20 Dec 2013 08:31:16 +0000 Received: by mail-qc0-f173.google.com with SMTP id m20so1950212qcx.32 for ; Fri, 20 Dec 2013 00:31:14 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.224.32.133 with SMTP id c5mr11363018qad.54.1387528273957; Fri, 20 Dec 2013 00:31:13 -0800 (PST) Received: by 10.229.239.197 with HTTP; Fri, 20 Dec 2013 00:31:13 -0800 (PST) In-Reply-To: <52B3CABE.1080903@hitachi.com> References: <20131219090353.14309.15496.stgit@kbuild-fedora.novalocal> <20131219090409.14309.25677.stgit@kbuild-fedora.novalocal> <52B3AD7D.2020104@hitachi.com> <52B3CABE.1080903@hitachi.com> Date: Fri, 20 Dec 2013 08:31:00 -0000 Message-ID: Subject: Re: [PATCH -tip v6 06/22] [BUGFIX] x86: Prohibit probing on memcpy/memset From: Jovi Zhangwei To: Masami Hiramatsu Cc: Ingo Molnar , linux-arch@vger.kernel.org, Ananth N Mavinakayanahalli , Sandeepa Prabhu , x86@kernel.org, lkml , "Steven Rostedt (Red Hat)" , Ingo Molnar , systemtap@sourceware.org, "H. Peter Anvin" , Thomas Gleixner , "David S. Miller" Content-Type: text/plain; charset=ISO-8859-1 X-SW-Source: 2013-q4/txt/msg00459.txt.bz2 On Fri, Dec 20, 2013 at 12:42 PM, Masami Hiramatsu wrote: > (2013/12/20 12:07), Jovi Zhangwei wrote: >> On Fri, Dec 20, 2013 at 10:37 AM, Masami Hiramatsu >> wrote: >>> Hi Jovi, >>> >>> (2013/12/19 18:37), Jovi Zhangwei wrote: >>>> Hi Masami, >>>> >>>> On Thu, Dec 19, 2013 at 5:04 PM, Masami Hiramatsu >>>> wrote: >>>>> memcpy/memset functions are fundamental functions and >>>>> those are involved in kprobe's exception handling. >>>>> Prohibit probing on them to avoid kernel crash. >>>>> >>>> Would you please let me know the LKML link of that bugfix, I cannot >>>> find it in my LKML fold. >>> >>> Yeah, that was found in my testing environment. >>> >>>> No objection on this patch. :) just want to know more, It seems there >>>> have no problem to probe memcpy in my box, maybe I didn't hit the >>>> crash code path. >>> >>> Ah, I see. Originally the problem happened when I put a probe on >>> __memcpy. And it looks the instances of memcpy and __memcpy are >>> same on x86-64. Thus I decided to blacklist both. (memset/__memset too) >>> Have you ever tried to probe __memcpy on your box? >>> >> Hmm, still no crash, __memcpy and __memset are both tested. >> >> I use below kprobe related config: >> >> CONFIG_KPROBES=y >> CONFIG_JUMP_LABEL=y >> CONFIG_OPTPROBES=y >> CONFIG_KPROBES_ON_FTRACE=y > > Hmm, I've added some debugging options. > > CONFIG_SLUB_DEBUG=y > CONFIG_X86_DEBUGCTLMSR=y > CONFIG_PNP_DEBUG_MESSAGES=y > CONFIG_DEBUG_INFO=y > CONFIG_DEBUG_FS=y > CONFIG_DEBUG_KERNEL=y > CONFIG_DEBUG_STACK_USAGE=y > CONFIG_DEBUG_MEMORY_INIT=y > CONFIG_DEBUG_STACKOVERFLOW=y > CONFIG_DEBUG_SPINLOCK=y > CONFIG_DEBUG_MUTEXES=y > CONFIG_DEBUG_LOCK_ALLOC=y > CONFIG_DEBUG_LOCKDEP=y > CONFIG_DEBUG_BUGVERBOSE=y > CONFIG_DEBUG_RODATA=y > CONFIG_DEBUG_BOOT_PARAMS=y > > I guess some of them might cause it. > I recompiled the kernel with those config enabled, unfortunately still no crash, I tested on 3.13.0-rc4, a fedora kvm box. Jovi