From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amit Shah Subject: Re: [PATCH v2 2/2] virtio: rng: ensure reads happen after successful probe Date: Thu, 10 Jul 2014 14:22:15 +0530 Message-ID: <20140710085215.GD3375@grmbl.mre> References: <20140709161836.GQ13433@titan.lakedaemon.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20140709161836.GQ13433@titan.lakedaemon.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jason Cooper Cc: herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Virtualization List , keescook@chromium.org List-Id: virtualization@lists.linuxfoundation.org On (Wed) 09 Jul 2014 [12:18:36], Jason Cooper wrote: > On Sat, Jul 05, 2014 at 11:04:53AM +0530, 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. > > > > CC: Kees Cook > > CC: Jason Cooper > > CC: Herbert Xu > > CC: # For v3.15+ > > Signed-off-by: Amit Shah > > --- > > drivers/char/hw_random/core.c | 6 ++++++ > > drivers/char/hw_random/virtio-rng.c | 10 ++++++++++ > > 2 files changed, 16 insertions(+) > > Yeah, I don't think there's any viable way to get random data out of > virtio-rng at probe time... :-( > > Reviewed-by: Jason Cooper Thanks! Amit