Am Donnerstag, 15. Juli 2021, 00:55:23 CEST 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
>
> 26
> 27 /*
> 28 * Have a static memory blocks for the ChaCha20 DRNG instance to
> avoid calling 29 * kmalloc too early in the boot cycle. For subsequent
> allocation requests, 30 * such as per-NUMA-node DRNG instances, kmalloc
> will be used. 31 */
>
> > 32 struct chacha20_state chacha20 __latent_entropy;
>
> 33
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
