Re: [PATCH RESEND] lib/test_printf.c: call wait_for_random_bytes() before plain %p tests

From: Thierry Escande <thierry.escande@linaro.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Miller <davem@davemloft.net>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	"Tobin C . Harding" <me@tobin.cc>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RESEND] lib/test_printf.c: call wait_for_random_bytes() before plain %p tests
Date: Fri, 8 Jun 2018 12:32:33 +0200	[thread overview]
Message-ID: <a8ab166e-a2b9-b0fc-9717-ffd8fcbcd386@linaro.org> (raw)
In-Reply-To: <CAHp75Vc5_+Kxsvgws9Oq-hOgbQ8-ocxeKa4AuhC0uJ0oKsu+BA@mail.gmail.com>

On 08/06/2018 11:46, Andy Shevchenko wrote:
> On Fri, Jun 8, 2018 at 12:07 PM, Thierry Escande
> <thierry.escande@linaro.org> wrote:
> 
>> But as I type I realize it's not necessary. I will simply enclose the call
>> to wait_for_random_bytes() by #if IS_MODULE() #endif so it gets called only
>> if built as a module, which is how run_kselftest.sh wants it... If
>> test_printf is compiled built-in and the crng is not yet initialized the
>> test will fail anyway so there is no need to add an extra check.
> 
> Unfortunately I can't support this as is.
> We have environments where crng will be ready minutes after the boot.
> It's unacceptable.
> 
> So, we need to have means to not delay test for so long.

I agree we can't delay test execution for too long. In my case the crng 
is ready only a few seconds after the boot. So we may just skip this 
plain 'p' printf test if crng is not ready then.

Regards,
Thierry