linux-kernel - Re: [PATCH] hw_random: don't wait on add_early

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Message-ID: <20190917124018.GA32437@gondor.apana.org.au>
Date:   Tue, 17 Sep 2019 22:40:18 +1000
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Laurent Vivier <lvivier@...hat.com>
Cc:     linux-kernel@...r.kernel.org, Amit Shah <amit@...nel.org>,
        linux-crypto@...r.kernel.org, Matt Mackall <mpm@...enic.com>
Subject: Re: [PATCH] hw_random: don't wait on add_early_randomness()

On Tue, Sep 17, 2019 at 11:54:50AM +0200, Laurent Vivier wrote:
> add_early_randomness() is called by hwrng_register() when the
> hardware is added. If this hardware and its module are present
> at boot, and if there is no data available the boot hangs until
> data are available and can't be interrupted.
> 
> To avoid that, call rng_get_data() in non-blocking mode (wait=0)
> from add_early_randomness().
> 
> Signed-off-by: Laurent Vivier <lvivier@...hat.com>
> ---
>  drivers/char/hw_random/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Please provide more context in your patch description such as which
driver actually causes a hang here.

Thanks,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt