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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 A26C6C3F2CD for ; Mon, 23 Mar 2020 14:00:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 775F020753 for ; Mon, 23 Mar 2020 14:00:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584972033; bh=exgRrTmUoY/hOqEmhXYfHo51IME1kdaFE/gpQs547BQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=m8NohP/NCbPKO57kdm1jFb1y/6zkiJ+pPPlcpcszBHXVIMN5lRnWF2HzBHB2hkfj/ 1dpQYWWVMVXz+4y0B+Y4RLGjtDTcZXesWZOaidAVpIn/QtaLctc3YfDXMrzxR0fRbX xYLpC8aZkrDwqQrNc8s3d91y/3hll9VV/Z9YFjMI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728607AbgCWOAc (ORCPT ); Mon, 23 Mar 2020 10:00:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:33692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728446AbgCWOAc (ORCPT ); Mon, 23 Mar 2020 10:00:32 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 9D4B62076A; Mon, 23 Mar 2020 14:00:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584972031; bh=exgRrTmUoY/hOqEmhXYfHo51IME1kdaFE/gpQs547BQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=hnN9lgoAuW0Z0z4uYsyccACHjB7hMDgg0zDpdxxyjn+4FQjkPt6C0mkYPRdZJptVx xIVFqCMvP6ZmfZPVCFlrpwd3cppNwBn1MsB4+J+MxhaCaA3v/HOvYmqmsJukLTlwFX A9l318vlJup0XGMIYVxwdQTcG+nAbad5kTN0i0b4= Date: Mon, 23 Mar 2020 23:00:25 +0900 From: Masami Hiramatsu To: Thomas Gleixner Cc: LKML , x86@kernel.org, Paul McKenney , Josh Poimboeuf , "Joel Fernandes (Google)" , "Steven Rostedt (VMware)" , Masami Hiramatsu , Alexei Starovoitov , Frederic Weisbecker , Mathieu Desnoyers , Brian Gerst , Juergen Gross , Alexandre Chartre , Peter Zijlstra , Tom Lendacky , Paolo Bonzini , kvm@vger.kernel.org Subject: Re: [patch V3 04/23] kprobes: Prevent probes in .noinstr.text section Message-Id: <20200323230025.a24f949a2143dbd5f208f00c@kernel.org> In-Reply-To: <20200320180032.799569116@linutronix.de> References: <20200320175956.033706968@linutronix.de> <20200320180032.799569116@linutronix.de> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, On Fri, 20 Mar 2020 19:00:00 +0100 Thomas Gleixner wrote: > Instrumentation is forbidden in the .noinstr.text section. Make kprobes > respect this. > > This lacks support for .noinstr.text sections in modules, which is required > to handle VMX and SVM. > Would you have any plan to list or mark the noinstr symbols on some debugfs interface? I need a blacklist of those symbols so that user (and perf-probe) can check which function can not be probed. It is just calling kprobe_add_area_blacklist() like below. diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 2625c241ac00..4835b644bd2b 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2212,6 +2212,10 @@ static int __init populate_kprobe_blacklist(unsigned long *start, ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start, (unsigned long)__kprobes_text_end); + /* Symbols in noinstr section are blacklisted */ + ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start, + (unsigned long)__noinstr_text_end); + return ret ? : arch_populate_kprobe_blacklist(); } Thank you, > Signed-off-by: Thomas Gleixner > --- > kernel/kprobes.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1443,10 +1443,21 @@ static bool __within_kprobe_blacklist(un > return false; > } > > +/* Functions in .noinstr.text must not be probed */ > +static bool within_noinstr_text(unsigned long addr) > +{ > + /* FIXME: Handle module .noinstr.text */ > + return addr >= (unsigned long)__noinstr_text_start && > + addr < (unsigned long)__noinstr_text_end; > +} > + > bool within_kprobe_blacklist(unsigned long addr) > { > char symname[KSYM_NAME_LEN], *p; > > + if (within_noinstr_text(addr)) > + return true; > + > if (__within_kprobe_blacklist(addr)) > return true; > > -- Masami Hiramatsu