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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 74AC9C3279B for ; Tue, 10 Jul 2018 18:29:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 428112083E for ; Tue, 10 Jul 2018 18:29:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 428112083E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387770AbeGJS33 (ORCPT ); Tue, 10 Jul 2018 14:29:29 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45324 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732245AbeGJS32 (ORCPT ); Tue, 10 Jul 2018 14:29:28 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 28FA2EC2; Tue, 10 Jul 2018 18:29:17 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masami Hiramatsu , Ananth N Mavinakayanahalli , Andrey Ryabinin , Anil S Keshavamurthy , Borislav Petkov , Brian Gerst , "David S . Miller" , Denys Vlasenko , "H. Peter Anvin" , Josh Poimboeuf , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ye Xiaolong , Ingo Molnar , "Steven Rostedt (VMware)" , Alexey Makhalov Subject: [PATCH 4.9 11/52] kprobes/x86: Do not modify singlestep buffer while resuming Date: Tue, 10 Jul 2018 20:24:39 +0200 Message-Id: <20180710182450.615940074@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180710182449.285532226@linuxfoundation.org> References: <20180710182449.285532226@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Masami Hiramatsu commit 804dec5bda9b4fcdab5f67fe61db4a0498af5221 upstream. Do not modify singlestep execution buffer (kprobe.ainsn.insn) while resuming from single-stepping, instead, modifies the buffer to add a jump back instruction at preparing buffer. Signed-off-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Andrey Ryabinin Cc: Anil S Keshavamurthy Cc: Borislav Petkov Cc: Brian Gerst Cc: David S . Miller Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ye Xiaolong Link: http://lkml.kernel.org/r/149076361560.22469.1610155860343077495.stgit@devbox Signed-off-by: Ingo Molnar Reviewed-by: "Steven Rostedt (VMware)" Signed-off-by: Alexey Makhalov Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/kprobes/core.c | 42 +++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 22 deletions(-) --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -414,25 +414,38 @@ void free_insn_page(void *page) module_memfree(page); } +/* Prepare reljump right after instruction to boost */ +static void prepare_boost(struct kprobe *p, int length) +{ + if (can_boost(p->ainsn.insn, p->addr) && + MAX_INSN_SIZE - length >= RELATIVEJUMP_SIZE) { + /* + * These instructions can be executed directly if it + * jumps back to correct address. + */ + synthesize_reljump(p->ainsn.insn + length, p->addr + length); + p->ainsn.boostable = 1; + } else { + p->ainsn.boostable = -1; + } +} + static int arch_copy_kprobe(struct kprobe *p) { - int ret; + int len; set_memory_rw((unsigned long)p->ainsn.insn & PAGE_MASK, 1); /* Copy an instruction with recovering if other optprobe modifies it.*/ - ret = __copy_instruction(p->ainsn.insn, p->addr); - if (!ret) + len = __copy_instruction(p->ainsn.insn, p->addr); + if (!len) return -EINVAL; /* * __copy_instruction can modify the displacement of the instruction, * but it doesn't affect boostable check. */ - if (can_boost(p->ainsn.insn, p->addr)) - p->ainsn.boostable = 0; - else - p->ainsn.boostable = -1; + prepare_boost(p, len); set_memory_ro((unsigned long)p->ainsn.insn & PAGE_MASK, 1); @@ -897,21 +910,6 @@ static void resume_execution(struct kpro break; } - if (p->ainsn.boostable == 0) { - if ((regs->ip > copy_ip) && - (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) { - /* - * These instructions can be executed directly if it - * jumps back to correct address. - */ - synthesize_reljump((void *)regs->ip, - (void *)orig_ip + (regs->ip - copy_ip)); - p->ainsn.boostable = 1; - } else { - p->ainsn.boostable = -1; - } - } - regs->ip += orig_ip - copy_ip; no_change: