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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_NEOMUTT 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 1407DC072B5 for ; Tue, 21 May 2019 21:00:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5FF3217F9 for ; Tue, 21 May 2019 21:00:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727723AbfEUVAY (ORCPT ); Tue, 21 May 2019 17:00:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52660 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726907AbfEUVAX (ORCPT ); Tue, 21 May 2019 17:00:23 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6C09937EE7; Tue, 21 May 2019 21:00:23 +0000 (UTC) Received: from treble (ovpn-125-173.rdu2.redhat.com [10.10.125.173]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 39180196F6; Tue, 21 May 2019 21:00:19 +0000 (UTC) Date: Tue, 21 May 2019 16:00:14 -0500 From: Josh Poimboeuf To: Joe Lawrence Cc: Johannes Erdfelt , Jessica Yu , Jiri Kosina , Miroslav Benes , Steven Rostedt , Ingo Molnar , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Oops caused by race between livepatch and ftrace Message-ID: <20190521210014.aoew7p7y3jbl7na4@treble> References: <20190520194915.GB1646@sventech.com> <90f78070-95ec-ce49-1641-19d061abecf4@redhat.com> <20190520210905.GC1646@sventech.com> <1802c0d2-702f-08ec-6a85-c7f887eb6d14@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 21 May 2019 21:00:23 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 21, 2019 at 03:27:47PM -0400, Joe Lawrence wrote: > BTW, livepatching folks -- speaking of this window, does it make sense for > klp_init_object_loaded() to unconditionally frob the module section > permissions? Should it only bother iff it's going to apply > relocations/alternatives/paravirt? Yeah, technically there shouldn't be a need to do the frobbing unless there are .klp.rela or .klp.arch sections for the given object. Though I'm not sure it really matters all that much since loading a livepatch is a pretty rare event. -- Josh