From: Mike Frysinger Subject: Re: [PATCH] hwrng: do not warn when there are no devices Date: Fri, 12 May 2017 02:41:53 -0400 Message-ID: References: <20170512041734.31945-1-vapier@gentoo.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Mike Frysinger , Matt Mackall , Herbert Xu , linux-crypto@vger.kernel.org To: PrasannaKumar Muralidharan Return-path: Received: from mail-ua0-f170.google.com ([209.85.217.170]:34372 "EHLO mail-ua0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750796AbdELGmZ (ORCPT ); Fri, 12 May 2017 02:42:25 -0400 Received: by mail-ua0-f170.google.com with SMTP id g49so41631069uaa.1 for ; Thu, 11 May 2017 23:42:25 -0700 (PDT) In-Reply-To: Sender: linux-crypto-owner@vger.kernel.org List-ID: On Fri, May 12, 2017 at 2:15 AM, PrasannaKumar Muralidharan wrote: > On 12 May 2017 at 09:47, Mike Frysinger wrote: > > From: Mike Frysinger > > > > If you build in hwrng & tpm-rng, but boot on a system that doesn't > > have a tpm (like via KVM), hwrng will spam the logs every 10 seconds > > with the line: > > hwrng: no data available > > > > This isn't terribly useful, so squelch the error in the ENODEV case. > > For all other errors, we still warn, and include the actual error. > > This patch removes the logging but does not fix the real problem. > Better method would be to start the hwrng_fillfn thread when first rng > provider registers and stop it when the last rng provider unregisters. what you describe is already implemented in the hw random code. the kthread only starts up when a registration happens, and will stop it when the last rng unregisters itself. the issue is that tpm-rng has registered itself here, but there aren't any tpm devices available. so it returns ENODEV. -mike