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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 F10AEC10F01 for ; Mon, 18 Feb 2019 12:26:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B6BD6218AD for ; Mon, 18 Feb 2019 12:26:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550492796; bh=lNKKnPuGUSMkXxUwapbfZcJqhufzShpsAeCuxIyiPyQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=adJ8m6LxUOh/O1/YuROVJwhqdm3nr/zNGPFTii02jCamQWATJPUZ075TPh6seaWZY pKRQwW0o6CZeKIwhW05XTTf09LjQLvOVETSq1/JD3ajmrFaCaMiNEQeNwHPHWDzRSz FTeBfta8B+QnHxBfvDahutEF60aK30OghiMf+Jyo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730866AbfBRM0f (ORCPT ); Mon, 18 Feb 2019 07:26:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:34058 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728874AbfBRM0f (ORCPT ); Mon, 18 Feb 2019 07:26:35 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B8113217F5; Mon, 18 Feb 2019 12:26:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550492794; bh=lNKKnPuGUSMkXxUwapbfZcJqhufzShpsAeCuxIyiPyQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VNic33GpUXkwI72zKwF58dPp8DN99wXqX2hiP2+lRbu6FreFoaHweKA12hvJPyhi0 kUNAoYu7KUKiPi48F3o54fkUmqXrMq0mGByjRpEJRK68NLzUbtupEUkDiHbWrShnP9 bxKfWXyL8XsPi4X64Ktix1IJPtfJMGnmLoowUags= Date: Mon, 18 Feb 2019 13:26:31 +0100 From: Greg KH To: Masami Hiramatsu Cc: Kees Cook , Mathieu Desnoyers , William Cohen , "# 3.4.x" , Laura Abbott , Russell King , linux-kernel , lttng@reliableembeddedsystems.com, lttng-dev Subject: Re: BUG: optimized kprobes illegal instructions in v4.19 stable kernels Message-ID: <20190218122631.GE30260@kroah.com> References: <342740659.2887.1549307721609.JavaMail.zimbra@efficios.com> <20190206134115.baba291e33022a2f6b6ae5f8@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190206134115.baba291e33022a2f6b6ae5f8@kernel.org> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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... thanks, greg k-h