From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC261C43381 for ; Mon, 18 Feb 2019 14:55:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ABE8E21479 for ; Mon, 18 Feb 2019 14:55:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="k2f3dj4t" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731138AbfBROzi (ORCPT ); Mon, 18 Feb 2019 09:55:38 -0500 Received: from mail.efficios.com ([167.114.142.138]:37070 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729907AbfBROzh (ORCPT ); Mon, 18 Feb 2019 09:55:37 -0500 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 724BAB1079; Mon, 18 Feb 2019 09:55:36 -0500 (EST) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id wSdFUddev7jS; Mon, 18 Feb 2019 09:55:35 -0500 (EST) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 6ABEAB106B; Mon, 18 Feb 2019 09:55:35 -0500 (EST) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 6ABEAB106B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1550501735; bh=dqICPl8GxPnt3Rpfa7GIh3OrSg7rfOI6RBVqZWpJ6Hw=; h=Date:From:To:Message-ID:MIME-Version; b=k2f3dj4tGsu2PlP+cJd5FOQ9hITSTZLzzx+Pa7qYOeFjssg9WSh9ccw9MUkjFIOft X25/vDix6x95v2PXp9S/Rr5Zku63DUKG4mnyUnPfnFlpgRCk9hKUOmzZLksD+d7DxH ZrmxlyXMblINfcBAHb+vxFUoUKuG8bq5t+cvjBzbr+QzEXfoRP6SbU1cekFJIvQ7dw YqM8g/6rU2mot8EqM5R5/F/kPZrhJxC5GS/5K/l2X0Zfw5A3U0i0XsIMWbzj6cMT4S 45JIs6rfXq0Wp4OlBrSMFJ4m9r/DEVuiON6di7jW+p+7b2sgur73942pUMty/okXgQ kJ83Ds2IMB7sw== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id TE65ajgzXElK; Mon, 18 Feb 2019 09:55:35 -0500 (EST) Received: from mail02.efficios.com (mail02.efficios.com [167.114.142.138]) by mail.efficios.com (Postfix) with ESMTP id 4C1F0B105F; Mon, 18 Feb 2019 09:55:35 -0500 (EST) Date: Mon, 18 Feb 2019 09:55:35 -0500 (EST) From: Mathieu Desnoyers To: Greg Kroah-Hartman , Linus Torvalds Cc: Masami Hiramatsu , Kees Cook , William Cohen , stable , Laura Abbott , Russell King , linux-kernel , lttng , lttng-dev Message-ID: <843587666.153.1550501735273.JavaMail.zimbra@efficios.com> In-Reply-To: <20190218122631.GE30260@kroah.com> References: <342740659.2887.1549307721609.JavaMail.zimbra@efficios.com> <20190206134115.baba291e33022a2f6b6ae5f8@kernel.org> <20190218122631.GE30260@kroah.com> Subject: Re: BUG: optimized kprobes illegal instructions in v4.19 stable kernels MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.142.138] X-Mailer: Zimbra 8.8.10_GA_3758 (ZimbraWebClient - FF65 (Linux)/8.8.10_GA_3745) Thread-Topic: optimized kprobes illegal instructions in v4.19 stable kernels Thread-Index: aysduGqTEJ/aj3gGSgj9LBgUddzFGg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- On Feb 18, 2019, at 7:26 AM, Greg Kroah-Hartman gregkh@linuxfoundation.org wrote: > On Wed, Feb 06, 2019 at 01:41:15PM +0900, Masami Hiramatsu wrote: >> On Tue, 5 Feb 2019 15:06:10 +0000 >> Kees Cook wrote: >> >> > On Mon, Feb 4, 2019 at 7:15 PM Mathieu Desnoyers >> > wrote: >> > > >> > > Hi, >> > > >> > > I notice this commit as a possible culprit of the illegal instructions my lttng >> > > users are noticing on arm32 when using kprobes on a v4.19.13 Linux kernel >> > > in a Yocto environment [1]. They were able to reproduce the issue with perf >> > > as well. >> > > >> > > commit e46daee53bb50bde38805f1823a182979724c229 >> > > Author: Kees Cook >> > > Date: Tue Oct 30 22:12:56 2018 +0100 >> > > >> > > ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE >> > > >> > > I *think* the intent there was to do >> > > >> > > - memcpy(code, &optprobe_template_entry, >> > > + memcpy(code, (unsigned long *)&optprobe_template_entry, >> > > >> > > But if you look at the commit, the "&" seems to have been stripped away, >> > > which happens to change the behavior significantly. >> > >> > Yeah, this was a typo on my part. :( >> >> Ah, I thought it had been fixed as same as x86. >> On x86, all optprobe_template_* are defined as kprobe_opcode_t [], >> but on arm, it still be kprobe_opcode_t. >> >> Hmm, but I think we should use kprobe_opcode_t [] or char[] as asm/sections.h >> does. >> OK, I'll prepare for the change. > > Did this ever get fixed in Linus's tree? If so, what is the git commit > id, I can't seem to find anything... It seems to still be in the arm patch tracking system: https://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=8834/1 If I understand its status correctly, it is applied to the arm tree, but perhaps it has not been pulled by Linus yet ? The code is still broken in Linus' master. It would be important to get this arm kprobes fix upstream before 5.0 final. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com