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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7CC6C433F5 for ; Fri, 20 May 2022 15:53:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351141AbiETPxo (ORCPT ); Fri, 20 May 2022 11:53:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351136AbiETPxd (ORCPT ); Fri, 20 May 2022 11:53:33 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B952166D7E for ; Fri, 20 May 2022 08:53:32 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id n18so7707968plg.5 for ; Fri, 20 May 2022 08:53:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=1ap+LN9xt8LVjDA6xeK3vWW8HvYkM4PsGmSQ2e/Kij0=; b=MugzJCkNjEQi0l6ih/P87UjZTcQUC/C1joaA+SjZDTpH/pYJB0Zh7vIU+k/9xb/7ZJ +9KT4tZgkLdq6OWRm92jC7M6jfNHeZTzZokLLM/saqP2xU5RODpljfuYNbH1YeVZexhH HsX+zFlPKvMnwzazJzc3DZ59x5rhgCU5SzTE56YZfqiaUnKv9LEy/P8ouHNFibhJpuLz LAAGbAT9TJiVSHSVOznyaC9ZvbcvhY/TXt7qje1eizJUM/K9qAZ7Zrv4L8V/EDzfwo13 as+4Q6zL8zqplnfZG7E/+HXoM2PeR4e23wWUpDCZ1BraX3lRsjeO+ZORZzcy43qoRkfA e2ww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=1ap+LN9xt8LVjDA6xeK3vWW8HvYkM4PsGmSQ2e/Kij0=; b=bHmwiCQPZk9MSXbukDyY3GTt8v8y8pO2spdKGCe0igiclelyC0lpr1qe0XqnNEzYfq DHt+H53tADUhzfu3xtIpGOcOgEHDaqgbSgW21SO7x4K6xS42VYFP7ecNqxDAAy/lRnuS jBDcOsdaLv2Iw3NXod132Ori5WtaCgU+r93UdsDO2njaJfxTfVf9K3Ss/JFeTYt7oMYe UZfIugMv3LQai6R2rT7R/QRU9a70a1Nped1zXG8c47YoCE1zFD7X8+hY4e4K6etDK+Gy sSeL2iAsm5pqlcTSoVTQiUv+cfHtxuY+KrUDZIsirpZHGsvcXjpHl+v7dPGIIdnQdijv 4Usg== X-Gm-Message-State: AOAM532KcfTgTdQJE4GZxUOz9DhAye32hblQ0l7dBi5YLnqMyr72bIm7 w84/qTlT6QV+G9rhtMJNVBhVVA== X-Google-Smtp-Source: ABdhPJwabxwPi8iNQy6HWxOrXPm+3cPn1tnBFJXUzMLocq2K/pMJt+MjbmSnwbVh2NIDFH7knNIp8w== X-Received: by 2002:a17:902:7048:b0:15f:34c1:bae0 with SMTP id h8-20020a170902704800b0015f34c1bae0mr10242169plt.71.1653062012098; Fri, 20 May 2022 08:53:32 -0700 (PDT) Received: from [192.168.1.100] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id v62-20020a622f41000000b0051835ccc008sm1940166pfv.115.2022.05.20.08.53.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 20 May 2022 08:53:31 -0700 (PDT) Message-ID: <7e78d6a7-1cc3-2408-fe91-0329f5020e77@kernel.dk> Date: Fri, 20 May 2022 09:53:30 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH v4 0/3] random: convert to using iters, for Al Viro Content-Language: en-US To: Al Viro Cc: "Jason A. Donenfeld" , Theodore Ts'o , Christoph Hellwig , LKML References: <20220520094459.116240-1-Jason@zx2c4.com> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/20/22 9:47 AM, Al Viro wrote: > On Fri, May 20, 2022 at 09:34:46AM -0600, Jens Axboe wrote: > >> I'm very sure, otherwise we're just accepting that we're breaking real >> world applications. > > "Breaking" as in "it used to work with earlier kernels, doesn't work with > recent ones"? Details, please... Yes, as in exactly that. This is what drove this addition of ->read_iter() for urandom. See commit: ommit 36e2c7421f02a22f71c9283e55fdb672a9eb58e7 Author: Christoph Hellwig Date: Thu Sep 3 16:22:34 2020 +0200 fs: don't allow splice read/write without explicit ops related to the set_fs() changes, and now go look for any commit that has: Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") in it and see that this isn't an isolated incident at all. tldr - splice from /dev/urandom used to work, and I recently got a report internally on an application that broke on upgrade from 5.6 to 5.12 exactly because it now just just -EINVAL's instead. -- Jens Axboe