Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751352AbaGGFvm (ORCPT ); Mon, 7 Jul 2014 01:51:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47578 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750714AbaGGFvk (ORCPT ); Mon, 7 Jul 2014 01:51:40 -0400 Date: Mon, 7 Jul 2014 11:21:07 +0530 From: Amit Shah To: Kees Cook Cc: LKML , Virtualization List , Rusty Russell , Herbert Xu , Jason Cooper , "# 3.4.x" Subject: Re: [PATCH v2 2/2] virtio: rng: ensure reads happen after successful probe Message-ID: <20140707055049.GA27024@grmbl.mre> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (Sun) 06 Jul 2014 [21:38:36], Kees Cook wrote: > On Fri, Jul 4, 2014 at 10:34 PM, Amit Shah wrote: > > The hwrng core asks for random data in the hwrng_register() call itself > > from commit d9e7972619. This doesn't play well with virtio -- the > > DRIVER_OK bit is only set by virtio core on a successful probe, and > > we're not yet out of our probe routine when this call is made. This > > causes the host to not acknowledge any requests we put in the virtqueue, > > and the insmod or kernel boot process just waits for data to arrive from > > the host, which never happens. > > Doesn't this mean that virtio-rng won't ever contribute entropy to the system? The initial randomness? Yes. But it'll start contributing entropy as soon as it's used as the current source. Is this a huge negative? Amit -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/