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=-1.1 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 402C9C3A5A2 for ; Tue, 10 Sep 2019 11:33:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12C6D20872 for ; Tue, 10 Sep 2019 11:33:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568115213; bh=623fYzFI8D1TaKyw1isaYldtSwGOQuKm+nvPmA7M2/c=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=o3Xw17LCnzsn17cM2sQkiWGQ1mdLAa+LF4IqYlLfrkwjrWAAEKj5IbvjKCm4+V337 kk60eydEK2Q84+CBEobiP4cT7zDFwm405sCWggVjsi6HuIJxkTX1cXydXgmAPlPX0V S68tHZZqq78Wpm1WJArG7+z8RDLiD+Die7KZBgVk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729170AbfIJLdc (ORCPT ); Tue, 10 Sep 2019 07:33:32 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:43294 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728537AbfIJLdc (ORCPT ); Tue, 10 Sep 2019 07:33:32 -0400 Received: by mail-lj1-f193.google.com with SMTP id d5so16047386lja.10 for ; Tue, 10 Sep 2019 04:33:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=/87kLUWhA8VGKwQ9ReDVfft5SDHkATRiA6uskomi3Do=; b=VPec9JRv8Tfx9xEc4r84woloylMuGNHPDiClO6km+SMR4SlGOn2EWxH8paATQU4SYk EdX0wUykyyflt8+WFj/VGKXZi/CVm+7AEyvwhPWJkWLBihBks9G66wETZBSNT1pzq08G a35JZGXi1OKWxuE5XkZCOuOYghEjdjQryubYo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=/87kLUWhA8VGKwQ9ReDVfft5SDHkATRiA6uskomi3Do=; b=bzJguR5+2mWZ7tg7Of5Q4qhIjiqIk0xqmfbpSTCsju2p4EqeP8cYQ0qGZuajsQL1Gr TF9DVJQTW3ZEyRJhfccQmY5juJgBfN/ZlD43y8I2ZLUI+CdVDOEBHtha3dxPE1/HupJ9 wrAJhgf9lrtnlr50qolU/yFGJ1nE5MWNV+/fXAjEyVmmuz4eZp693+HgjhcTDf4HVKo9 XXsC8MS7HhYmS4GF75A2Fb6lQyfKV7JiBpbKPdmGBY6VgnkYTFYxw3ZW2Mwg7pbi9k0k BAPf0JoJ+KU31AIGAo4fTMrFpSuTpEOd0sl+eCYQ91aZgoW55u59zo6kctnTF/ZrbK9G lpfw== X-Gm-Message-State: APjAAAWLG7C79FeqazrBiE8NkCunU4uejtaEX+UQZ4cgej8BpF7Ozqx4 Nj3NiRXO1/9mzjkTkwgdIYC4DLECv3ZtXg== X-Google-Smtp-Source: APXvYqxszH7hz0Hr38fm/MEjo+S1ejDXzqg5Z23iFovu5SPMdpFE/Yvbf0zMeUOBBdp/xxcL0l/FSA== X-Received: by 2002:a2e:8611:: with SMTP id a17mr15767865lji.130.1568115209723; Tue, 10 Sep 2019 04:33:29 -0700 (PDT) Received: from mail-lj1-f179.google.com (mail-lj1-f179.google.com. [209.85.208.179]) by smtp.gmail.com with ESMTPSA id d8sm3775371ljj.59.2019.09.10.04.33.28 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Sep 2019 04:33:28 -0700 (PDT) Received: by mail-lj1-f179.google.com with SMTP id a22so16090537ljd.0 for ; Tue, 10 Sep 2019 04:33:28 -0700 (PDT) X-Received: by 2002:a2e:3c14:: with SMTP id j20mr18756186lja.84.1568115208066; Tue, 10 Sep 2019 04:33:28 -0700 (PDT) MIME-Version: 1.0 References: <20190910042107.GA1517@darwi-home-pc> In-Reply-To: <20190910042107.GA1517@darwi-home-pc> From: Linus Torvalds Date: Tue, 10 Sep 2019 12:33:12 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: Linux 5.3-rc8 To: "Ahmed S. Darwish" Cc: "Theodore Ts'o" , Andreas Dilger , Jan Kara , zhangjs , linux-ext4@vger.kernel.org, Linux List Kernel Mailing Content-Type: text/plain; charset="UTF-8" Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Sep 10, 2019 at 5:21 AM Ahmed S. Darwish wrote: > > The commit b03755ad6f33 (ext4: make __ext4_get_inode_loc plug), [1] > which was merged in v5.3-rc1, *always* leads to a blocked boot on my > system due to low entropy. Exactly what is it that blocks on entropy? Nobody should do that during boot, because on some systems entropy is really really low (think flash memory with polling IO etc). That said, I would have expected that any PC gets plenty of entropy. Are you sure it's entropy that is blocking, and not perhaps some odd "forgot to unplug" situation? > Can this even be considered a user-space breakage? I'm honestly not > sure. On my modern RDRAND-capable x86, just running rng-tools rngd(8) > early-on fixes the problem. I'm not sure about the status of older > CPUs though. It's definitely breakage, although rather odd. I would have expected us to have other sources of entropy than just the disk. Did we stop doing low bits of TSC from timer interrupts etc? Ted, either way - ext4 IO patterns or random number entropy - this is your code. Comments? Linus