static int skcipher_prepare_alg(struct skcipher_alg *alg)
{
	struct crypto_alg *base = &alg->base;

	if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8 ||
	    alg->walksize > PAGE_SIZE / 8)
		return -EINVAL;

	if (!alg->chunksize)
		alg->chunksize = base->cra_blocksize;
	if (!alg->walksize)
		alg->walksize = alg->chunksize;

	base->cra_type = &crypto_skcipher_type2;
	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
	base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;

	return 0;
}

The product dereferences a pointer that it expects to be valid but is NULL.