From mboxrd@z Thu Jan 1 00:00:00 1970 From: Masami Hiramatsu Subject: Re: [PATCH -tip v6 06/22] [BUGFIX] x86: Prohibit probing on memcpy/memset Date: Fri, 20 Dec 2013 13:42:38 +0900 Message-ID: <52B3CABE.1080903@hitachi.com> References: <20131219090353.14309.15496.stgit@kbuild-fedora.novalocal> <20131219090409.14309.25677.stgit@kbuild-fedora.novalocal> <52B3AD7D.2020104@hitachi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail7.hitachi.co.jp ([133.145.228.42]:44608 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752088Ab3LTEmq (ORCPT ); Thu, 19 Dec 2013 23:42:46 -0500 In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Jovi Zhangwei 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" (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. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com