ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 143 insertions, 0 deletions

diff --git a/net/rxrpc/tests/Makefile b/net/rxrpc/tests/Makefile
new file mode 100644
index 000000000..4f5100880
--- /dev/null
+++ b/net/rxrpc/tests/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_AF_RXRPC_KUNIT_TEST) += rxrpc_kunit.o
diff --git a/net/rxrpc/tests/rxrpc_kunit.c b/net/rxrpc/tests/rxrpc_kunit.c
new file mode 100644
index 000000000..95fd05a07
--- /dev/null
+++ b/net/rxrpc/tests/rxrpc_kunit.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Unit tests for RxRPC crypto functions
+ *
+ * Copyright 2026 Google LLC
+ */
+#include "../ar-internal.h"
+#include <crypto/des.h>
+#include <kunit/test.h>
+
+struct fcrypt_pcbc_testvec {
+	u8 key[FCRYPT_BSIZE];
+	u8 iv[FCRYPT_BSIZE];
+	const u8 *ptext; /* plaintext */
+	const u8 *ctext; /* ciphertext */
+	size_t nblocks; /* length of ptext and ctext in blocks */
+};
+
+/* FCrypt-PCBC test vectors */
+static const struct fcrypt_pcbc_testvec fcrypt_pcbc_testvecs[] = {
+	{
+		/* http://www.openafs.org/pipermail/openafs-devel/2000-December/005320.html */
+		.key = "\x00\x00\x00\x00\x00\x00\x00\x00",
+		.iv = "\x00\x00\x00\x00\x00\x00\x00\x00",
+		.ptext = "\x00\x00\x00\x00\x00\x00\x00\x00",
+		.ctext = "\x0E\x09\x00\xC7\x3E\xF7\xED\x41",
+		.nblocks = 1,
+	},
+	{
+		.key = "\x11\x44\x77\xAA\xDD\x00\x33\x66",
+		.iv = "\x00\x00\x00\x00\x00\x00\x00\x00",
+		.ptext = "\x12\x34\x56\x78\x9A\xBC\xDE\xF0",
+		.ctext = "\xD8\xED\x78\x74\x77\xEC\x06\x80",
+		.nblocks = 1,
+	},
+	{
+		/* From Arla */
+		.key = "\xf0\xe1\xd2\xc3\xb4\xa5\x96\x87",
+		.iv = "\xfe\xdc\xba\x98\x76\x54\x32\x10",
+		.ptext = "The quick brown fox jumps over the lazy dogs.\0\0",
+		.ctext = "\x00\xf0\x0e\x11\x75\xe6\x23\x82"
+			 "\xee\xac\x98\x62\x44\x51\xe4\x84"
+			 "\xc3\x59\xd8\xaa\x64\x60\xae\xf7"
+			 "\xd2\xd9\x13\x79\x72\xa3\x45\x03"
+			 "\x23\xb5\x62\xd7\x0c\xf5\x27\xd1"
+			 "\xf8\x91\x3c\xac\x44\x22\x92\xef",
+		.nblocks = 6,
+	},
+	{
+		.key = "\xfe\xdc\xba\x98\x76\x54\x32\x10",
+		.iv = "\xf0\xe1\xd2\xc3\xb4\xa5\x96\x87",
+		.ptext = "The quick brown fox jumps over the lazy dogs.\0\0",
+		.ctext = "\xca\x90\xf5\x9d\xcb\xd4\xd2\x3c"
+			 "\x01\x88\x7f\x3e\x31\x6e\x62\x9d"
+			 "\xd8\xe0\x57\xa3\x06\x3a\x42\x58"
+			 "\x2a\x28\xfe\x72\x52\x2f\xdd\xe0"
+			 "\x19\x89\x09\x1c\x2a\x8e\x8c\x94"
+			 "\xfc\xc7\x68\xe4\x88\xaa\xde\x0f",
+		.nblocks = 6,
+	}
+};
+
+static void test_fcrypt_pcbc(struct kunit *test)
+{
+	u8 data[48];
+
+	for (size_t i = 0; i < ARRAY_SIZE(fcrypt_pcbc_testvecs); i++) {
+		const struct fcrypt_pcbc_testvec *tv = &fcrypt_pcbc_testvecs[i];
+		const size_t nblocks = tv->nblocks;
+		const size_t len = nblocks * FCRYPT_BSIZE;
+		struct fcrypt_key key;
+
+		KUNIT_ASSERT_GE(test, sizeof(data), len);
+
+		fcrypt_preparekey(&key, tv->key);
+
+		/* out-of-place encryption */
+		fcrypt_pcbc_encrypt(&key, tv->iv, tv->ptext, data, nblocks);
+		KUNIT_ASSERT_MEMEQ(test, tv->ctext, data, len);
+
+		/* in-place encryption */
+		memcpy(data, tv->ptext, len);
+		fcrypt_pcbc_encrypt(&key, tv->iv, data, data, nblocks);
+		KUNIT_ASSERT_MEMEQ(test, tv->ctext, data, len);
+
+		/* out-of-place decryption */
+		fcrypt_pcbc_decrypt(&key, tv->iv, tv->ctext, data, nblocks);
+		KUNIT_ASSERT_MEMEQ(test, tv->ptext, data, len);
+
+		/* in-place decryption */
+		memcpy(data, tv->ctext, len);
+		fcrypt_pcbc_decrypt(&key, tv->iv, data, data, nblocks);
+		KUNIT_ASSERT_MEMEQ(test, tv->ptext, data, len);
+	}
+}
+
+static void test_des_pcbc(struct kunit *test)
+{
+	/* This was generated from the original pcbc(des) crypto API code. */
+	static const u8 expected_ptext[24] =
+		"\xc8\xe2\x3c\xdf\x80\x61\x8a\xad\xa5\x52\xb4\x20"
+		"\x74\x32\x1f\xe4\x2c\x15\x7d\x21\x57\xda\x3f\x31";
+	u8 key[8];
+	union {
+		__le64 w;
+		u8 b[8];
+	} iv;
+	u8 data[24];
+	struct des_ctx ctx;
+	int err;
+
+	for (int i = 0; i < 8; i++) {
+		key[i] = i;
+		iv.b[i] = 255 - i;
+	}
+	for (int i = 0; i < sizeof(data); i++)
+		data[i] = i;
+
+	err = des_expand_key(&ctx, key, sizeof(key));
+	KUNIT_ASSERT_EQ(test, 0, err);
+
+	des_pcbc_decrypt_inplace(&ctx, iv.w, data, sizeof(data));
+	KUNIT_ASSERT_MEMEQ(test, expected_ptext, data, sizeof(data));
+}
+
+static struct kunit_case rxrpc_test_cases[] = {
+	KUNIT_CASE(test_fcrypt_pcbc),
+	KUNIT_CASE(test_des_pcbc),
+	{},
+};
+
+static struct kunit_suite rxrpc_test_suite = {
+	.name = "rxrpc",
+	.test_cases = rxrpc_test_cases,
+};
+kunit_test_suite(rxrpc_test_suite);
+
+MODULE_DESCRIPTION("Unit tests for RxRPC crypto functions");
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
+MODULE_LICENSE("GPL");