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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 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 2D829C47082 for ; Mon, 7 Jun 2021 14:52:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 04EB561108 for ; Mon, 7 Jun 2021 14:52:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230217AbhFGOyQ (ORCPT ); Mon, 7 Jun 2021 10:54:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:37184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230254AbhFGOyL (ORCPT ); Mon, 7 Jun 2021 10:54:11 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 F368F60FE5; Mon, 7 Jun 2021 14:52:18 +0000 (UTC) Date: Mon, 7 Jun 2021 10:52:17 -0400 From: Steven Rostedt To: Mark-PK Tsai Cc: , , , , , , , Subject: Re: [PATCH] arm64: ftrace: don't dereference a probably invalid address Message-ID: <20210607105217.772214e5@oasis.local.home> In-Reply-To: <20210607141522.3281-1-mark-pk.tsai@mediatek.com> References: <20210607095518.12694437@oasis.local.home> <20210607141522.3281-1-mark-pk.tsai@mediatek.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 7 Jun 2021 22:15:22 +0800 Mark-PK Tsai wrote: > And the crash is becuase kernel trying to read *rec->ip in print_ip_ins() if > ftrace_bug() get error code -EINVAL. Right, so the actual fix should be something like this: [ not tested, nor even compiled ] -- Steve diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2e8a3fde7104..72ef4dccbcc4 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1967,12 +1967,18 @@ static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, static void print_ip_ins(const char *fmt, const unsigned char *p) { + char ins[MCOUNT_INSN_SIZE]; int i; + if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) { + printk(KERN_CONT "%s[FAULT](%px)", fmt, p); + return; + } + printk(KERN_CONT "%s", fmt); for (i = 0; i < MCOUNT_INSN_SIZE; i++) - printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); + printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]); } enum ftrace_bug_type ftrace_bug_type;