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 97660C433DF for ; Thu, 4 Jun 2020 16:47:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 691862072E for ; Thu, 4 Jun 2020 16:47:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="c95W5F7V" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729932AbgFDQrm (ORCPT ); Thu, 4 Jun 2020 12:47:42 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:28842 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729856AbgFDQrk (ORCPT ); Thu, 4 Jun 2020 12:47:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591289258; 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=c95W5F7VEA/C633Hto+WBSZsYwLCINSQ5IWspfELy7vqfITu0rxIzrLl6JPCUmhl4QnaiV ft2fLhYpYhgdPHsI+E7hBRmr6rHEyOMjeMtZZNS2HW8mYEygGWg2IWve8rY1ZtYQ/7hvk8 Jen92RRirT9qfIRZ01uB/ort2wSLfmI= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-231-t4N_9AzwMvSWa7F-Ayy4VA-1; Thu, 04 Jun 2020 12:47:35 -0400 X-MC-Unique: t4N_9AzwMvSWa7F-Ayy4VA-1 Received: by mail-wr1-f71.google.com with SMTP id j16so2626016wre.22 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=iGc8S2IaFUaA58zS/ZXioghPQMY3b93cTRVayey54RzwSOMTIiPLYt6VM0vWrqpqTC YgmrBOyQ8nnBfobs+Gy+qe8PAUuHyssPbUUwWT/zo2vn0fIj6x1gfFMogDQ9HgEFotyq KYCQJBKGdEkNe2r422I4Z9/CDxOi30lffLJDHgwMEhOCpOpftC5nMVf/g1Tb1ebHIpz3 1L6Q600RZAVw8RuRDNzmiW6cDopSfTB0WfrbvCpqhafJpImYNRpmq14r7IhEYyc9E9C2 kQP7ZaiJlRhJx8ozBh3rLSB84dfsHRHYA8Nzedrnb92Atcpzr8V4a7eDuTisnwd1+WFt SK7Q== X-Gm-Message-State: AOAM532a/8XcQ0KIrq+eFxfukGtIrYGKPXjXhuYWXcUU1CV/DjGbebD9 S23D/sgVwIYxIe2q9i5eWw3L98JhDn4bX2qABVU77ierYRMdseJavS/HPHrxfCvRr+nm5IRNByU H6CbPQZJjyz9UBaWsoLk55GrY X-Received: by 2002:a5d:40d0:: with SMTP id b16mr5209775wrq.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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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