Re: [PATCH v43 01/15] Linux Random Number Generator

[Stephan Mueller]

Am Montag, 22. November 2021, 11:33:26 CET schrieb kernel test robot:

Hi,

> All errors (new ones prefixed by >>):
> >> drivers/char/lrng/lrng_chacha20.c:32:8: error: structure variable
> >> 'chacha20' with 'latent_entropy' attribute has a non-integer field
> >> 'block'
>       32 | struct chacha20_state chacha20 __latent_entropy;
> 
>          |        ^~~~~~~~~~~~~~
> 
> vim +32 drivers/char/lrng/lrng_chacha20.c

Thanks for the notification.

I think this is a false-positive discussed before. __latent_entropy is 
seemingly allowed for an entire linear buffer as seen in the declaration of 
the variable input_pool_data in driver/char/random.c which is an array of u32.

The struct chacha20_state is a linear buffer of u32 words. 

struct chacha20_block {
        u32 constants[4];
        union {
                u32 u[CHACHA_KEY_SIZE_WORDS];
                u8  b[CHACHA_KEY_SIZE];
        } key;
        u32 counter;
        u32 nonce[3];
};

Therefore it should be identical to the aforementioned example. The 
__latent_entropy marker therefore seems to be appropriate for this structure.

Ciao
Stephan