linux-kernel - Re: random: /dev/random often returns short reads

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Message-ID: <CAK1hOcOwSph_P6EXGWde_MLwQSbqwh1dE-pc8PTHGPpG6yRtLg@mail.gmail.com>
Date:   Mon, 16 Jan 2017 19:52:04 +0100
From:   Denys Vlasenko <vda.linux@...glemail.com>
To:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Theodore Ts'o" <tytso@....edu>,
        "H. Peter Anvin" <hpa@...ux.intel.com>,
        Denys Vlasenko <dvlasenk@...hat.com>
Subject: Re: random: /dev/random often returns short reads

> # while ./eat_dev_random; do ./eat_dev_random; done; ./eat_dev_random
> read of 32 returns 32
> read of 32 returns 32
> read of 32 returns 28
> read of 32 returns 24
>
> Just two few first requests worked, and then ouch...
>
> I think this is what happens here:
> we transfer 4 bytes of entrophy to /dev/random pool:


erm... 32 bytes, of course.