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

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Message-ID: <20180427000013.GH5965@thunk.org>
Date:   Thu, 26 Apr 2018 20:00:13 -0400
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Christian Brauner <christian.brauner@...onical.com>
Cc:     Sultan Alsawaf <sultanxda@...il.com>, linux-kernel@...r.kernel.org,
        Jann Horn <jannh@...gle.com>
Subject: Re: Linux messages full of `random: get_random_u32 called from`

On Thu, Apr 26, 2018 at 10:47:49PM +0200, Christian Brauner wrote:
> 
> We have observed a similiar problem  with libvirt. As soon as entropy is
> provided the boot finishes otherwise it hangs for a long time.
> This is not happening with v4.17-rc1 afaict.

For libvirt there is at least an easy workaround.  Make surue the
guest kernel has CONFIG_HW_RANDOM_VIRTIO enabled, and then make sure
qemu is started with the options:

	-object rng-random,filename=/dev/urandom,id=rng0 \
	-device virtio-rng-pci,rng=rng0

Cheers,

					- Ted