linux-kernel - Re: [PATCH] lib/test_printf.c: call wait_for_random

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Date:   Wed, 23 May 2018 08:01:40 +1000
From:   "Tobin C . Harding" <me@...in.cc>
To:     Thierry Escande <thierry.escande@...aro.org>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] lib/test_printf.c: call wait_for_random_bytes() before
 plain %p tests

On Tue, May 22, 2018 at 07:41:14PM +0200, Thierry Escande wrote:
> If the test_printf module is loaded before the crng is initialized, the
> plain 'p' tests will fail because the printed address will not be hashed
> and the buffer will contain '(ptrval)' instead.
> This patch adds a call to wait_for_random_bytes() before plain 'p' tests
> to make sure the crng is initialized.
> 
> Signed-off-by: Thierry Escande <thierry.escande@...aro.org>
> ---
>  lib/test_printf.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/lib/test_printf.c b/lib/test_printf.c
> index 71ebfa43ad05..839be9385a8a 100644
> --- a/lib/test_printf.c
> +++ b/lib/test_printf.c
> @@ -260,6 +260,13 @@ plain(void)
>  {
>  	int err;
>  
> +	/*
> +	 * Make sure crng is ready. Otherwise we get "(ptrval)" instead
> +	 * of a hashed address when printing '%p' in plain_hash() and
> +	 * plain_format().
> +	 */
> +	wait_for_random_bytes();
> +
>  	err = plain_hash();
>  	if (err) {
>  		pr_warn("plain 'p' does not appear to be hashed\n");
> -- 
> 2.14.1

Not sure if I'm qualified for this but here goes

Acked-by: Tobin C. Harding <me@...in.cc>

thanks,
Tobin.