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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 50455C432C0 for ; Sat, 23 Nov 2019 22:53:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E38B2064B for ; Sat, 23 Nov 2019 22:53:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="umVxDiOO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726759AbfKWWxg (ORCPT ); Sat, 23 Nov 2019 17:53:36 -0500 Received: from mail-pj1-f67.google.com ([209.85.216.67]:35393 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726638AbfKWWxg (ORCPT ); Sat, 23 Nov 2019 17:53:36 -0500 Received: by mail-pj1-f67.google.com with SMTP id s8so4735171pji.2 for ; Sat, 23 Nov 2019 14:53:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=jiZxXT1E7B694H4PHITbBBtth5SFMvT8DMla8FvvNB0=; b=umVxDiOOmmPEoOgWTWg1QoOxu19E7sTKKi+33E8Emw2dZn6iGsKfNCry/Zw8QIHptL 15PPpIhzWvg6rmlWKH6b4GYv3/5G35C+BvLP8G5nbdbyrgqQ0bylQy0OgJir1TYBB59O q+mRHTFjk2btwCnbCnBc6VUsuxDdMkrV0Ki/EeT1f4eMQqEDVKeksZPfwNTZfQO9mB/m 2wZQ9JBkmwh77pLzVojZ3nJuFWSfTElcyb9nOWnToaYjTQ8gDrSTYW7hPayC0Pil3EvQ JtkmgCkH4GyrfRYgIN34g11eq21o1BAWpXv6XQlinKvSJm8QEtTQIo1rySkCSiUEisEx +IdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=jiZxXT1E7B694H4PHITbBBtth5SFMvT8DMla8FvvNB0=; b=ckymFS4Hx9ottatqWelhoDMZ1ldrIJqBkU8niYTcwdqAhd7dwuKEbH7t/kWes3qRZ9 bJ3mpxCEs693ZJ+VKsQclMO3DnSjsjyYXJMgl8XlO5QAGaRbNHB2w2pOsIMBvO7u7wKk aQaRNtuJMqqqPFlewO+Y3KiWAXx5ppBeVt8ynt/lSDjKchxBSErL17jVCuxJg7lIKIvE 5yCVZD2OJ4eUGd2LL8/Q54mQiIKbhcIhEMSQ+iGtCXjYqy2dpdeuMqDWKhUSCuQ5iOAk ETIOFYdhR0dZFZx0IdJO8d5gqOc6WF2vZifIPXyLhjrL6ZlWeVnm7drEoi2+68ZMLNzw M7yA== X-Gm-Message-State: APjAAAUzEgNS9Lxy8oN6Y1lORLSTeVs5feC63dzPz5/e7mzQuprYvo6a sesf141tgZMWcqX1waxfeQFaaYk457T+lA== X-Google-Smtp-Source: APXvYqwYFsut1/v433tkRVNruQFY4t555nHfg3f/OSMZ/46HCRHwCt0PhIncfrXZOSSQvu0jnNy3rQ== X-Received: by 2002:a17:902:b945:: with SMTP id h5mr21442545pls.326.1574549615099; Sat, 23 Nov 2019 14:53:35 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.79]) by smtp.gmail.com with ESMTPSA id 21sm2776325pfy.67.2019.11.23.14.53.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 23 Nov 2019 14:53:34 -0800 (PST) Subject: Re: [RFC 0/2] fix in-kernel segfault To: Pavel Begunkov , io-uring@vger.kernel.org References: From: Jens Axboe Message-ID: <6627f75d-2b03-fc6f-997e-15e5700a642a@kernel.dk> Date: Sat, 23 Nov 2019 15:53:33 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 11/23/19 3:49 PM, Pavel Begunkov wrote: > There is a bug hunging my system when run fixed-link with /dev/urandom > instead of /dev/zero (see patch 1/2). > > As for me, the easiest way to fix is to grab mm and use userspace > address for this specific case (as it's done in patches). The other > way is to kmap/vmap, but the first should be short-lived and the > second needs mm anyway. > > Ideas how to do it better way? Suggestions and corrections are welcome. > > P.S. It seems for some reason it fails a bunch of unrelated tests, > that's POC and not meant to be applied yet. I'll take a look at this, but probably not until tomorrow afternoon or Monday. -- Jens Axboe