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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 D1660C433E0 for ; Thu, 4 Jun 2020 16:47:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC9C72072E for ; Thu, 4 Jun 2020 16:47:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JKDlcDid" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729909AbgFDQrj (ORCPT ); Thu, 4 Jun 2020 12:47:39 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:54453 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728587AbgFDQrj (ORCPT ); Thu, 4 Jun 2020 12:47:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591289257; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0Ar15+z0tlu8GE0Wg5KZSeq2GZEzeqWT+aUmm+wx7x4=; b=JKDlcDidL2Gw8r+tRUM3Q1eDKDdgbwOHBOW+NFJWNDo2S2UHrwVUFtcBllNb1uqXQPWiFj mjgwom8Px1AZNOAVZP6vEXTxij7e4+Y1OKg8hZJzN4rLxAPOwmI19135gmq9PLP7JUSX1C b4UqU9gz6EdGUTanr84/QSQPYNuvTi4= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-205-X1YOkOV6OlqrVF6jr_Psbw-1; Thu, 04 Jun 2020 12:47:35 -0400 X-MC-Unique: X1YOkOV6OlqrVF6jr_Psbw-1 Received: by mail-wm1-f69.google.com with SMTP id y202so1972524wmd.0 for ; Thu, 04 Jun 2020 09:47:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=0Ar15+z0tlu8GE0Wg5KZSeq2GZEzeqWT+aUmm+wx7x4=; b=jxjwZCJFnTPYWm7qQX/qQx09ksQnpo1QgsY1WIfeRnBbjIB2+rXh2aPEa9+IuL0Lqi rn2nWg+enOYc4edl/iqfh4QVpK1PFeXR+wJ+uus6NsCSA0llrQW778SUmK44e3BhKS9i sv9OrDB7KhGiKIXe6BqlRhWfvpi4VahQaz4z0MHLyh24A0dPH9JZ19/8dSW/oZ2cxoak ndg4A9Oy/tYguILi5vqprJBqFTl8hpz2qx3ennc+9v4XldbvkH/kjCo3nqf11GXGV9u3 L+zYvTbMukDPXiSPSQUljTOrRRQrqGer0wj3w0Ug65hiptG8qm+yrAq0I9W29lNt0tHE jazw== X-Gm-Message-State: AOAM532eeO0NlvfV9uz0d5/eiJztCMYiP3cwURkObgJnf3OnBKAhCAKI PmYxdMLTstQ/NqpITQoqXzRlAPs/j8fwXLXgxQNrOSGytK2LSxUKWH0wQpyxLwF7T9I3FvQpQG+ CyIO0AzkpwG76q3o6 X-Received: by 2002:a5d:40d0:: with SMTP id b16mr5209774wrq.218.1591289254184; Thu, 04 Jun 2020 09:47:34 -0700 (PDT) X-Google-Smtp-Source: ABdhPJz/oB1XkJnvn++j/58MNAY5P5qdvPGtsdrzBj0W/ri36XSP6zrbEREeugPFE4b1qeLilItQwQ== X-Received: by 2002:a5d:40d0:: with SMTP id b16mr5209770wrq.218.1591289254041; Thu, 04 Jun 2020 09:47:34 -0700 (PDT) Received: from redhat.com (bzq-109-64-41-91.red.bezeqint.net. [109.64.41.91]) by smtp.gmail.com with ESMTPSA id v6sm118202wrf.61.2020.06.04.09.47.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jun 2020 09:47:33 -0700 (PDT) Date: Thu, 4 Jun 2020 12:47:31 -0400 From: "Michael S. Tsirkin" To: Al Viro Cc: linux-kernel@vger.kernel.org, Jason Wang , netdev@vger.kernel.org Subject: Re: [PATCH RFC] uaccess: user_access_begin_after_access_ok() Message-ID: <20200604124703-mutt-send-email-mst@kernel.org> References: <20200602084257.134555-1-mst@redhat.com> <20200603014815.GR23230@ZenIV.linux.org.uk> <20200603011810-mutt-send-email-mst@kernel.org> <20200603165205.GU23230@ZenIV.linux.org.uk> <20200604054516-mutt-send-email-mst@kernel.org> <20200604150335.GG23230@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200604150335.GG23230@ZenIV.linux.org.uk> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Jun 04, 2020 at 04:03:35PM +0100, Al Viro wrote: > On Thu, Jun 04, 2020 at 06:10:23AM -0400, Michael S. Tsirkin wrote: > > > stac() > > for (i = 0; i < 64; ++i) { > > get_user(flags, desc[i].flags) > unsafe_get_user(), please. > > smp_rmb() > > if (!(flags & VALID)) > > break; > > copy_from_user(&adesc[i], desc + i, sizeof adesc[i]); > ... and that would raw_copy_from_user() (or unsafe_copy_from_user(), > for wrapper that would take a label to bugger off to) > > } > > clac() Absolutely, that's all just pseudo-code. -- MST