x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 73 insertions, 0 deletions

diff --git a/net/mptcp/crypto_test.c b/net/mptcp/crypto_test.c
new file mode 100644
index 000000000..220414e5c
--- /dev/null
+++ b/net/mptcp/crypto_test.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+
+#include "protocol.h"
+
+struct test_case {
+	char *key;
+	char *msg;
+	char *result;
+};
+
+/* we can't reuse RFC 4231 test vectors, as we have constraint on the
+ * input and key size.
+ */
+static struct test_case tests[] = {
+	{
+		.key = "0b0b0b0b0b0b0b0b",
+		.msg = "48692054",
+		.result = "8385e24fb4235ac37556b6b886db106284a1da671699f46db1f235ec622dcafa",
+	},
+	{
+		.key = "aaaaaaaaaaaaaaaa",
+		.msg = "dddddddd",
+		.result = "2c5e219164ff1dca1c4a92318d847bb6b9d44492984e1eb71aff9022f71046e9",
+	},
+	{
+		.key = "0102030405060708",
+		.msg = "cdcdcdcd",
+		.result = "e73b9ba9969969cefb04aa0d6df18ec2fcc075b6f23b4d8c4da736a5dbbc6e7d",
+	},
+};
+
+static void mptcp_crypto_test_basic(struct kunit *test)
+{
+	char hmac[32], hmac_hex[65];
+	u32 nonce1, nonce2;
+	u64 key1, key2;
+	u8 msg[8];
+	int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(tests); ++i) {
+		/* mptcp hmap will convert to be before computing the hmac */
+		key1 = be64_to_cpu(*((__be64 *)&tests[i].key[0]));
+		key2 = be64_to_cpu(*((__be64 *)&tests[i].key[8]));
+		nonce1 = be32_to_cpu(*((__be32 *)&tests[i].msg[0]));
+		nonce2 = be32_to_cpu(*((__be32 *)&tests[i].msg[4]));
+
+		put_unaligned_be32(nonce1, &msg[0]);
+		put_unaligned_be32(nonce2, &msg[4]);
+
+		mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
+		for (j = 0; j < 32; ++j)
+			sprintf(&hmac_hex[j << 1], "%02x", hmac[j] & 0xff);
+		hmac_hex[64] = 0;
+
+		KUNIT_EXPECT_STREQ(test, &hmac_hex[0], tests[i].result);
+	}
+}
+
+static struct kunit_case mptcp_crypto_test_cases[] = {
+	KUNIT_CASE(mptcp_crypto_test_basic),
+	{}
+};
+
+static struct kunit_suite mptcp_crypto_suite = {
+	.name = "mptcp-crypto",
+	.test_cases = mptcp_crypto_test_cases,
+};
+
+kunit_test_suite(mptcp_crypto_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KUnit tests for MPTCP Crypto");