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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 295A6C43387 for ; Mon, 17 Dec 2018 18:31:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 008532086C for ; Mon, 17 Dec 2018 18:31:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388131AbeLQSbv (ORCPT ); Mon, 17 Dec 2018 13:31:51 -0500 Received: from mga04.intel.com ([192.55.52.120]:15532 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388003AbeLQSbv (ORCPT ); Mon, 17 Dec 2018 13:31:51 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Dec 2018 10:31:51 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,366,1539673200"; d="scan'208";a="108080947" Received: from quwen-mobl.ccr.corp.intel.com (HELO localhost) ([10.249.254.215]) by fmsmga007.fm.intel.com with ESMTP; 17 Dec 2018 10:31:45 -0800 Date: Mon, 17 Dec 2018 20:31:44 +0200 From: Jarkko Sakkinen To: Dave Hansen Cc: x86@kernel.org, platform-driver-x86@vger.kernel.org, linux-sgx@vger.kernel.org, sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@linux.intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, mark.shanahan@intel.com, luto@amacapital.net, Suresh Siddha , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Darren Hart , Andy Shevchenko , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH v17 18/23] platform/x86: Intel SGX driver Message-ID: <20181217183144.GA26507@linux.intel.com> References: <20181116010412.23967-1-jarkko.sakkinen@linux.intel.com> <20181116010412.23967-19-jarkko.sakkinen@linux.intel.com> <7d5cde02-4649-546b-0f03-2d6414bb80b5@intel.com> <20181217180102.GA12560@linux.intel.com> <2f2bef3d-c0e5-1bea-fc9d-58cd367a982d@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2f2bef3d-c0e5-1bea-fc9d-58cd367a982d@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, Dec 17, 2018 at 10:07:08AM -0800, Dave Hansen wrote: > On 12/17/18 10:01 AM, Jarkko Sakkinen wrote: > >>> + encl->mm = current->mm; <---------------------------------> + encl->base = secs->base; > >>> + encl->size = secs->size; > >>> + encl->ssaframesize = secs->ssa_frame_size; > >>> + encl->backing = backing; > >>> + > >>> + return encl; > >>> +} > >> How is this OK without taking a reference on the mm? > >> > >> I have a feeling a bunch of your bugs with the mmu notifiers and so > >> forth are because the refcounting is wrong here. > >> > >> Sean's SGX_ENCL_MM_RELEASED would, I think be unnecessary if you just > >> take a refcount here and release it when the enclave is destroyed. > > Right, atomic_inc(encl->mm->count) here and once when releasing. > > > > The we would not even need the whole mmu notifier in the first place. > > Please use mmget()/mmput(). There's now a patch to test on top of the master. /Jarkko