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 264C3C433EF for ; Sun, 1 May 2022 17:26:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352926AbiEAR3k (ORCPT ); Sun, 1 May 2022 13:29:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231484AbiEAR3g (ORCPT ); Sun, 1 May 2022 13:29:36 -0400 Received: from mail-oa1-x2d.google.com (mail-oa1-x2d.google.com [IPv6:2001:4860:4864:20::2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64B82BE12 for ; Sun, 1 May 2022 10:26:10 -0700 (PDT) Received: by mail-oa1-x2d.google.com with SMTP id 586e51a60fabf-ed9ac77cbbso1996862fac.1 for ; Sun, 01 May 2022 10:26:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:message-id:date:mime-version:user-agent:from:subject:to:cc :content-language:content-transfer-encoding; bh=pI+qY9/hirlSNjBDN43HbEPTPB6DnELjIcqxHY4iYSM=; b=lEmg2o4Jcwec6tRJGHz/2fgZaeertWvBPVzXVQ70FoParo6dqwW7L3sMzmqIrisHG9 45JSmVzOLJhGM/2braFZ0LvfTaq8p00M7V4jQ2YxtvKo9RtScTieJCvaJE3jvGmQKnq+ kowSRNHp4D9VAVj6ieVbif0N2SvCvAGyzV/Rl8q9DAJoKC80W37L22mRra1/iZn5bWiV +EYjstV1UEoZuJNHQ8z6Ww07ohOHT5YA9FIky0znIWk2t99sN41dmQAzXiIR/wZ9/u0q OIrNL9CbOe4ih9n3MQ/gx5YL0uLoy2O3QgILH8gMsMdjedLm6Tym4nPXagf7qbhr0tAK KNWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:message-id:date:mime-version:user-agent :from:subject:to:cc:content-language:content-transfer-encoding; bh=pI+qY9/hirlSNjBDN43HbEPTPB6DnELjIcqxHY4iYSM=; b=eGdO0ZsQRiO+EsMoZBu2yVTPqJ27S5YYav3Poo10Ad37i4ecHrXbLTiACFnaZBEZj/ lhXENO8I7tOTcS1OER61vaI38kQeY2K4WAKSLZOdlNuWgfH8WApA/yxXH6XvajNku3hZ seef8dkYq/IOzMrTR+/hUkoG4TjbpEWrkWG3wcbGesFrg1VOR54c3YvpUZmVy1gCCfDV 2+M4YLmmnJ4UxPe3wn/xsNp86YQ7sLtpgiG4dVDzy+jgJrnEahtVIrzfzdak4MVOAQL4 eWhLjTCiKtVtg7NArfWzhywGRoc44jvj0e7X4S2Ogog8iXNC3eAMQLi4Tf+fO2vJk3r5 Vesg== X-Gm-Message-State: AOAM532ntkS28R+iJ+wS12edM4U3AS+vnxgoDJbIHAyFBIyu1mCq9+Wj KT8KLCiF7TVug5Kx7ixrOtmElux0rEsiEg== X-Google-Smtp-Source: ABdhPJzs7W3+fcYn/a9QX4d78CRazvy9tcpwS72hZ2BRJr7wqLCWwclb2QsAIF2KVakLF6IXvNZGFQ== X-Received: by 2002:a05:6871:112:b0:ec:f449:5af8 with SMTP id y18-20020a056871011200b000ecf4495af8mr2991414oab.76.1651425969776; Sun, 01 May 2022 10:26:09 -0700 (PDT) Received: from ?IPV6:2603:8090:2005:39b3::100e? (2603-8090-2005-39b3-0000-0000-0000-100e.res6.spectrum.com. [2603:8090:2005:39b3::100e]) by smtp.gmail.com with ESMTPSA id l2-20020a4ad9c2000000b0035eb4e5a6b7sm3066960oou.13.2022.05.01.10.26.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 01 May 2022 10:26:09 -0700 (PDT) Sender: Larry Finger Message-ID: <7f01221d-f693-adf8-f5a5-d71944b44162@lwfinger.net> Date: Sun, 1 May 2022 12:26:07 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 From: Larry Finger Subject: Changes in kernel 5.18-rc1 leads to crashes in VirtualBox Virtual Machines To: "Jason A. Donenfeld" Cc: LKML Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jason, I maintain VirtualBox for openSUSE. When kernel 5.18-rc1 was released, I fixed the usual set of API changes needed to compile the external kernel modules for VB. Despite a clean compile, I am still getting random crashes in the VMs. For Linux instances, the desktop disappears, but for Windows guests, the VM crashes with unhandled kernel exceptions. As I have no experience tracing such crashes, I decided to bisect the kernel to find the commit that started these problems. Surprisingly, the bisection pointed to commit 6e8ec2552c7d ("random: use computational hash for entropy extraction"). I am very sure of the bisection as the kernel built from the commit that immediately precedes this one, cfb92440ee71 - a tag commit by Linus, runs correctly. Note that I do not believe there is anything wrong with your changes to the random number generators. It seems to be a problem with the way the emulator is accessing them. The VirtualBox code is quite complicated, and I am no expert with C++. Are there changes that would be required to the X86_64 emulator's access to the random number code as a result of your changes? I have found places where the emulator accesses /dev/urandom or /dev/random. There are also places that use the rdrand and reseed instructions. Thanks for reading this, Larry