From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: Re: [PATCH v3 05/13] security/keys: ensure RNG is seeded before use
Date: Tue, 6 Jun 2017 14:23:09 +0200
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Cc: "Theodore Ts'o" <tytso@mit.edu>,
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To: David Howells <dhowells@redhat.com>
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On Tue, Jun 6, 2017 at 12:08 PM, David Howells <dhowells@redhat.com> wrote:
> Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
>> +             key->serial = get_random_u32() >> 1;
>
> If this may sleep, it must be interruptible.

That won't sleep. I could have made it get_random_u32_wait(), but we'd
get into trouble at boottime. So instead, for now, I just use
get_random_u32 rather than get_random_bytes, which can use the
architectural random number generator, when the platform has one,
which is available early on.