crypto: testmgr - don't use stack buffer in test_acomp()

With virtually-mapped stacks (CONFIG_VMAP_STACK=y), using the
scatterlist crypto API with stack buffers is not allowed, and with
appropriate debugging options will cause the
'BUG_ON(!virt_addr_valid(buf));' in sg_set_buf() to be triggered.
Use a heap buffer instead.

Fixes: d7db7a88 ("crypto: acomp - update testmgr with support for acomp")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/testmgr.c

@@ -1448,17 +1448,21 @@ static int test_acomp(struct crypto_acomp *tfm, struct comp_testvec *ctemplate,
 {
 	const char *algo = crypto_tfm_alg_driver_name(crypto_acomp_tfm(tfm));
 	unsigned int i;
-	char output[COMP_BUF_SIZE];
+	char *output;
 	int ret;
 	struct scatterlist src, dst;
 	struct acomp_req *req;
 	struct tcrypt_result result;
 
+	output = kmalloc(COMP_BUF_SIZE, GFP_KERNEL);
+	if (!output)
+		return -ENOMEM;
+
 	for (i = 0; i < ctcount; i++) {
 		unsigned int dlen = COMP_BUF_SIZE;
 		int ilen = ctemplate[i].inlen;
 
-		memset(output, 0, sizeof(output));
+		memset(output, 0, dlen);
 		init_completion(&result.completion);
 		sg_init_one(&src, ctemplate[i].input, ilen);
 		sg_init_one(&dst, output, dlen);
@@ -1507,7 +1511,7 @@ static int test_acomp(struct crypto_acomp *tfm, struct comp_testvec *ctemplate,
 		unsigned int dlen = COMP_BUF_SIZE;
 		int ilen = dtemplate[i].inlen;
 
-		memset(output, 0, sizeof(output));
+		memset(output, 0, dlen);
 		init_completion(&result.completion);
 		sg_init_one(&src, dtemplate[i].input, ilen);
 		sg_init_one(&dst, output, dlen);
@@ -1555,6 +1559,7 @@ static int test_acomp(struct crypto_acomp *tfm, struct comp_testvec *ctemplate,
 	ret = 0;
 
 out:
+	kfree(output);
 	return ret;
 }