linux-kernel - Re: Linux messages full of `random: get_random

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Message-ID: <2add15cb-2113-0504-a732-81255ea61bf5@gmail.com>
Date:   Thu, 26 Apr 2018 13:22:02 -0700
From:   Sultan Alsawaf <sultanxda@...il.com>
To:     "Theodore Y. Ts'o" <tytso@....edu>, linux-kernel@...r.kernel.org,
        Jann Horn <jannh@...gle.com>
Subject: Re: Linux messages full of `random: get_random_u32 called from`

> Hmm, it looks like the multiuser startup is getting blocked on snapd:
>
>          29.060s snapd.service
>
> graphical.target @1min 32.145s
> └─multi-user.target @1min 32.145s
>   └─hddtemp.service @6.512s +28ms
>     └─network-online.target @6.508s
>       └─NetworkManager-wait-online.service @2.428s +4.079s
>         └─NetworkManager.service @2.016s +404ms
>           └─dbus.service @1.869s
>             └─basic.target @1.824s
>               └─sockets.target @1.824s
>                 └─snapd.socket @1.821s +1ms
>                   └─sysinit.target @1.812s
>                     └─apparmor.service @587ms +1.224s
>                       └─local-fs.target @585ms
>                         └─local-fs-pre.target @585ms
>                           └─keyboard-setup.service @235ms +346ms
>                             └─systemd-journald.socket @226ms
>                               └─system.slice @225ms
>                                 └─-.slice @220ms
>
> This appears to be some kind of new package management system for
> Ubuntu:
>
> Description-en: Tool to interact with Ubuntu Core Snappy.
>  Install, configure, refresh and remove snap packages. Snaps are
>  'universal' packages that work across many different Linux systems,
>  enabling secure distribution of the latest apps and utilities for
>  cloud, servers, desktops and the internet of things.
>
> Why it the Ubuntu package believes it needs to be fully started before
> the login screen can display is unclear to me.  It might be worth
> using systemctl to disable snapd.serivce and see if that makes things
> work better for you.
>
> 				- Ted

I removed snapd completely which did nothing.

Here are new logs:
systemd-analyze blame: https://hastebin.com/edehikuyeb.css
systemd-analyze critical-chain: https://hastebin.com/vedufafema.pl
dmesg: https://hastebin.com/zuwuwoxadu.vbs

I should also note that leaving the system untouched does not result in it booting: I must
provide a source of entropy, otherwise it just stays stuck. In both of the dmesgs I've given, I
manually provided entropy to the system after about 5 minutes of waiting.

Also, regardless of what's hanging on CRNG init, CRNG should be able to init on its own in a timely
manner without the need for user-provided entropy. Userspace was working fine before the recent CRNG
kernel changes, so I don't think this is a userspace bug.

-Sultan