linux-kernel - [v2 PATCH] crypto: lib/blake2s - Split up test function to halve stack usage

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Date:   Wed, 21 Dec 2022 14:58:08 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Eric Biggers <ebiggers@...nel.org>
Cc:     "Chen, Rong A" <rong.a.chen@...el.com>,
        kernel test robot <lkp@...el.com>,
        "Jason A. Donenfeld" <zx2c4@...nel.org>,
        oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Linux Crypto Mailing List <linux-crypto@...r.kernel.org>
Subject: [v2 PATCH] crypto: lib/blake2s - Split up test function to halve
 stack usage

On Tue, Dec 20, 2022 at 08:34:18PM +0000, Eric Biggers wrote:
>
> Shouldn't these functions have 'noinline_for_stack' added to them?

Indeed they should.  Thanks!

---8<---
Reduce the stack usage further by splitting up the test function.

Also squash blocks and unaligned_blocks into one array.

Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>

diff --git a/lib/crypto/blake2s-selftest.c b/lib/crypto/blake2s-selftest.c
index 7d77dea15587..d0634ed6a937 100644
--- a/lib/crypto/blake2s-selftest.c
+++ b/lib/crypto/blake2s-selftest.c
@@ -545,7 +545,7 @@ static const u8 blake2s_testvecs[][BLAKE2S_HASH_SIZE] __initconst = {
     0xd6, 0x98, 0x6b, 0x07, 0x10, 0x65, 0x52, 0x65, },
 };
 
-bool __init blake2s_selftest(void)
+static bool __init noinline_for_stack blake2s_digest_test(void)
 {
 	u8 key[BLAKE2S_KEY_SIZE];
 	u8 buf[ARRAY_SIZE(blake2s_testvecs)];
@@ -589,11 +589,20 @@ bool __init blake2s_selftest(void)
 		}
 	}
 
+	return success;
+}
+
+static bool __init noinline_for_stack blake2s_random_test(void)
+{
+	struct blake2s_state state;
+	bool success = true;
+	int i, l;
+
 	for (i = 0; i < 32; ++i) {
 		enum { TEST_ALIGNMENT = 16 };
-		u8 unaligned_block[BLAKE2S_BLOCK_SIZE + TEST_ALIGNMENT - 1]
+		u8 blocks[BLAKE2S_BLOCK_SIZE * 2 + TEST_ALIGNMENT - 1]
 					__aligned(TEST_ALIGNMENT);
-		u8 blocks[BLAKE2S_BLOCK_SIZE * 2];
+		u8 *unaligned_block = blocks + BLAKE2S_BLOCK_SIZE;
 		struct blake2s_state state1, state2;
 
 		get_random_bytes(blocks, sizeof(blocks));
@@ -630,3 +639,13 @@ bool __init blake2s_selftest(void)
 
 	return success;
 }
+
+bool __init blake2s_selftest(void)
+{
+	bool success;
+
+	success = blake2s_digest_test();
+	success &= blake2s_random_test();
+
+	return success;
+}
-- 
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