linux-kernel - Re: [PATCH v2] random32: avoid attempt to late reseed if in the middle of seeding

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Message-ID: <20140327061742.GM22086@order.stressinduktion.org>
Date:	Thu, 27 Mar 2014 07:17:42 +0100
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	Sasha Levin <sasha.levin@...cle.com>
Cc:	davem@...emloft.net, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, tytso@....edu, dborkman@...hat.com
Subject: Re: [PATCH v2] random32: avoid attempt to late reseed if in the middle of seeding

On Thu, Mar 27, 2014 at 02:01:35AM -0400, Sasha Levin wrote:
> Commit 4af712e8df ("random32: add prandom_reseed_late() and call when
> nonblocking pool becomes initialized") has added a late reseed stage
> that happens as soon as the nonblocking pool is marked as initialized.
> 
> This fails in the case that the nonblocking pool gets initialized
> during __prandom_reseed()'s call to get_random_bytes(). In that case
> we'd double back into __prandom_reseed() in an attempt to do a late
> reseed - deadlocking on 'lock' early on in the boot process.
> 
> Instead, just avoid even waiting to do a reseed if a reseed is already
> occuring.
> 
> Signed-off-by: Sasha Levin <sasha.levin@...cle.com>

Thanks for fixing this!

Acked-by: Hannes Frederic Sowa <hannes@...essinduktion.org>

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