From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752852AbdDKFoW (ORCPT ); Tue, 11 Apr 2017 01:44:22 -0400 Received: from mail.kernel.org ([198.145.29.136]:50234 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751824AbdDKFoV (ORCPT ); Tue, 11 Apr 2017 01:44:21 -0400 Date: Tue, 11 Apr 2017 14:44:13 +0900 From: Masami Hiramatsu To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Thomas Gleixner , "H . Peter Anvin" , Ananth N Mavinakayanahalli , Anil S Keshavamurthy , "David S . Miller" , Andrey Ryabinin , Ye Xiaolong Subject: Re: [RFC PATCH tip/master V3 0/8] kprobes/x86: Make kprobes instruction buffers read-only Message-Id: <20170411144413.7f04cf0ec89de1d3362d8dca@kernel.org> In-Reply-To: <149076333370.22469.11135086121721120819.stgit@devbox> References: <149076333370.22469.11135086121721120819.stgit@devbox> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping? On Wed, 29 Mar 2017 13:55:44 +0900 Masami Hiramatsu wrote: > Hi, > > This is the 3rd version of the series. I just updated 4/8 according > to Ingo's comment. > > This series tries to make kprobes instruction buffers read-only > pages. Since those buffers are used for trampoline code, those > are a part of "text area" and it should be marked as ro for > avoiding unexpected modification. And this actually fix a warning > rodata sanity check reported by lkp-robot. > > https://lkml.org/lkml/2017/2/27/161 > > This change requires changing the kprobe-booster at first > because it can modify the instruction buffer to add a jump while > resuming from single-stepping. Of course after we make the buffer > readonly, we may not be able to modify it while probing. > > So, at first this series checks the current bootable instructions > and fixes a missed instruction (call far), modifies can_boost to > use x86 instruction decoder, and inserts "booster" jump while > preparing instruction buffer instead of resuming from single-stepping. > At last, it makes the buffers for kprobes and optprobe readonly. > > This series also has some cleanup patches related to above > changes. > > Changes from V2: > - [4/8]: Fix imbalanced curly braces and remove unneeded > (void *) cast. > > --- > > Masami Hiramatsu (8): > kprobes/x86: Fix not to boost call far instruction > kprobes/x86: Fix the description of __copy_instruction() > kprobes/x86: Use instruction decoder for booster > kprobes/x86: Do not modify singlestep buffer while resuming > kprobes/x86: Make boostable flag boolean > kprobes/x86: Set kprobes pages readonly > kprobes/x86: Use probe_kernel_read instead of memcpy > kprobes/x86: Consolidate insn decoder users for copying code > > > arch/x86/include/asm/kprobes.h | 7 +- > arch/x86/kernel/kprobes/common.h | 4 + > arch/x86/kernel/kprobes/core.c | 149 +++++++++++++++++++------------------- > arch/x86/kernel/kprobes/ftrace.c | 2 - > arch/x86/kernel/kprobes/opt.c | 13 +++ > 5 files changed, 90 insertions(+), 85 deletions(-) > > -- > Masami Hiramatsu (Linaro) -- Masami Hiramatsu