From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Weber Date: Tue, 19 May 2020 17:08:23 -0500 Subject: [Buildroot] [PATCH] package/rng-tools: make jitterentropy conditional In-Reply-To: <20200518094817.3996c1b1@windsurf.home> References: <20200205182608.22695-1-matthew.weber@rockwellcollins.com> <20200205203257.48877881@windsurf> <87wo8wuc3z.fsf@dell.be.48ers.dk> <20200518094817.3996c1b1@windsurf.home> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Thomas, On Mon, May 18, 2020 at 2:49 AM Thomas Petazzoni wrote: > > Hello Matt, > > On Thu, 13 Feb 2020 11:07:36 -0600 > Matthew Weber wrote: > > > > We had similar issue today with am335x (kernel 5.4.x). Bumping > > > rng-tools to v6.9 helped. > > > > Thank you for that feedback, I'll make this patch is superseded as the > > bump resolved the bug. I'll add a note with this patchwork thread in > > the bug report as well. > > As I was going through open bug reports, I looked again at > https://bugs.busybox.net/show_bug.cgi?id=12511, and I disagree with the > conclusion of discarding this patch "package/rng-tools: make > jitterentropy conditional". > > If I understand correctly: > > - If you have a hardware RNG, the jitterentropy library is not > necessary. > Right, jitterentropy is a fall back if there isn't a hardware RNG setup. The performance impacts of having it enabled when there is a hardware RNG were improved between versions and that was the motivation to drop this patch as it didn't seem to still be a bug (having it enabled when it isn't really needed). > - If you don't have a hardware RNG, rng-tools will error out, unless > jitterentropy support is enabled. Correct. > > So, we really want to make the jitterentropy support in rng-tools > optional, and leave it up to the user to enable it if (s)he has no > hardware RNG available. And if there's no hardware RNG and no > jitterentropy support, rng-tools will error out, the service will fail > to start, and that's good. So the trick with the special 66 return code > is not necessary. > > Do you agree ? I agree, we should drop that rngd.service change but still keep the option where a user could add the jitterentropy library if they need it. Regards, Matt