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>

1 files changed, 294 insertions, 0 deletions

diff --git a/lib/tests/base64_kunit.c b/lib/tests/base64_kunit.c
new file mode 100644
index 000000000..f7252070c
--- /dev/null
+++ b/lib/tests/base64_kunit.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * base64_kunit_test.c - KUnit tests for base64 encoding and decoding functions
+ *
+ * Copyright (c) 2025, Guan-Chun Wu <409411716@gms.tku.edu.tw>
+ */
+
+#include <kunit/test.h>
+#include <linux/base64.h>
+
+/* ---------- Benchmark helpers ---------- */
+static u64 bench_encode_ns(const u8 *data, int len, char *dst, int reps,
+			   enum base64_variant variant)
+{
+	u64 t0, t1;
+
+	t0 = ktime_get_ns();
+	for (int i = 0; i < reps; i++)
+		base64_encode(data, len, dst, true, variant);
+	t1 = ktime_get_ns();
+
+	return div64_u64(t1 - t0, (u64)reps);
+}
+
+static u64 bench_decode_ns(const char *data, int len, u8 *dst, int reps,
+			   enum base64_variant variant)
+{
+	u64 t0, t1;
+
+	t0 = ktime_get_ns();
+	for (int i = 0; i < reps; i++)
+		base64_decode(data, len, dst, true, variant);
+	t1 = ktime_get_ns();
+
+	return div64_u64(t1 - t0, (u64)reps);
+}
+
+static void run_perf_and_check(struct kunit *test, const char *label, int size,
+			       enum base64_variant variant)
+{
+	const int reps = 1000;
+	size_t outlen = DIV_ROUND_UP(size, 3) * 4;
+	u8 *in = kmalloc(size, GFP_KERNEL);
+	char *enc = kmalloc(outlen, GFP_KERNEL);
+	u8 *decoded = kmalloc(size, GFP_KERNEL);
+
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, in);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, enc);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, decoded);
+
+	get_random_bytes(in, size);
+	int enc_len = base64_encode(in, size, enc, true, variant);
+	int dec_len = base64_decode(enc, enc_len, decoded, true, variant);
+
+	/* correctness sanity check */
+	KUNIT_EXPECT_EQ(test, dec_len, size);
+	KUNIT_EXPECT_MEMEQ(test, decoded, in, size);
+
+	/* benchmark encode */
+
+	u64 t1 = bench_encode_ns(in, size, enc, reps, variant);
+
+	kunit_info(test, "[%s] encode run : %lluns", label, t1);
+
+	u64 t2 = bench_decode_ns(enc, enc_len, decoded, reps, variant);
+
+	kunit_info(test, "[%s] decode run : %lluns", label, t2);
+
+	kfree(in);
+	kfree(enc);
+	kfree(decoded);
+}
+
+static void base64_performance_tests(struct kunit *test)
+{
+	/* run on STD variant only */
+	run_perf_and_check(test, "64B", 64, BASE64_STD);
+	run_perf_and_check(test, "1KB", 1024, BASE64_STD);
+}
+
+/* ---------- Helpers for encode ---------- */
+static void expect_encode_ok(struct kunit *test, const u8 *src, int srclen,
+			     const char *expected, bool padding,
+			     enum base64_variant variant)
+{
+	char buf[128];
+	int encoded_len = base64_encode(src, srclen, buf, padding, variant);
+
+	buf[encoded_len] = '\0';
+
+	KUNIT_EXPECT_EQ(test, encoded_len, strlen(expected));
+	KUNIT_EXPECT_STREQ(test, buf, expected);
+}
+
+/* ---------- Helpers for decode ---------- */
+static void expect_decode_ok(struct kunit *test, const char *src,
+			     const u8 *expected, int expected_len, bool padding,
+			     enum base64_variant variant)
+{
+	u8 buf[128];
+	int decoded_len = base64_decode(src, strlen(src), buf, padding, variant);
+
+	KUNIT_EXPECT_EQ(test, decoded_len, expected_len);
+	KUNIT_EXPECT_MEMEQ(test, buf, expected, expected_len);
+}
+
+static void expect_decode_err(struct kunit *test, const char *src,
+			      int srclen, bool padding,
+			      enum base64_variant variant)
+{
+	u8 buf[64];
+	int decoded_len = base64_decode(src, srclen, buf, padding, variant);
+
+	KUNIT_EXPECT_EQ(test, decoded_len, -1);
+}
+
+/* ---------- Encode Tests ---------- */
+static void base64_std_encode_tests(struct kunit *test)
+{
+	/* With padding */
+	expect_encode_ok(test, (const u8 *)"", 0, "", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"f", 1, "Zg==", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fo", 2, "Zm8=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foo", 3, "Zm9v", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foob", 4, "Zm9vYg==", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fooba", 5, "Zm9vYmE=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foobar", 6, "Zm9vYmFy", true, BASE64_STD);
+
+	/* Extra cases with padding */
+	expect_encode_ok(test, (const u8 *)"Hello, world!", 13, "SGVsbG8sIHdvcmxkIQ==",
+			 true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26,
+			 "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26,
+			 "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"0123456789+/", 12, "MDEyMzQ1Njc4OSsv",
+			 true, BASE64_STD);
+
+	/* Without padding */
+	expect_encode_ok(test, (const u8 *)"", 0, "", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"f", 1, "Zg", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fo", 2, "Zm8", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foo", 3, "Zm9v", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foob", 4, "Zm9vYg", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fooba", 5, "Zm9vYmE", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foobar", 6, "Zm9vYmFy", false, BASE64_STD);
+
+	/* Extra cases without padding */
+	expect_encode_ok(test, (const u8 *)"Hello, world!", 13, "SGVsbG8sIHdvcmxkIQ",
+			 false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26,
+			 "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26,
+			 "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"0123456789+/", 12, "MDEyMzQ1Njc4OSsv",
+			 false, BASE64_STD);
+}
+
+/* ---------- Decode Tests ---------- */
+static void base64_std_decode_tests(struct kunit *test)
+{
+	/* -------- With padding --------*/
+	expect_decode_ok(test, "", (const u8 *)"", 0, true, BASE64_STD);
+	expect_decode_ok(test, "Zg==", (const u8 *)"f", 1, true, BASE64_STD);
+	expect_decode_ok(test, "Zm8=", (const u8 *)"fo", 2, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9v", (const u8 *)"foo", 3, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYg==", (const u8 *)"foob", 4, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmE=", (const u8 *)"fooba", 5, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmFy", (const u8 *)"foobar", 6, true, BASE64_STD);
+	expect_decode_ok(test, "SGVsbG8sIHdvcmxkIQ==", (const u8 *)"Hello, world!", 13,
+			 true, BASE64_STD);
+	expect_decode_ok(test, "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo=",
+			 (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26, true, BASE64_STD);
+	expect_decode_ok(test, "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo=",
+			 (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26, true, BASE64_STD);
+
+	/* Error cases */
+	expect_decode_err(test, "Zg=!", 4, true, BASE64_STD);
+	expect_decode_err(test, "Zm$=", 4, true, BASE64_STD);
+	expect_decode_err(test, "Z===", 4, true, BASE64_STD);
+	expect_decode_err(test, "Zg", 2, true, BASE64_STD);
+	expect_decode_err(test, "Zm9v====", 8, true, BASE64_STD);
+	expect_decode_err(test, "Zm==A", 5, true, BASE64_STD);
+
+	{
+		char with_nul[4] = { 'Z', 'g', '\0', '=' };
+
+		expect_decode_err(test, with_nul, 4, true, BASE64_STD);
+	}
+
+	/* -------- Without padding --------*/
+	expect_decode_ok(test, "", (const u8 *)"", 0, false, BASE64_STD);
+	expect_decode_ok(test, "Zg", (const u8 *)"f", 1, false, BASE64_STD);
+	expect_decode_ok(test, "Zm8", (const u8 *)"fo", 2, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9v", (const u8 *)"foo", 3, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYg", (const u8 *)"foob", 4, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmE", (const u8 *)"fooba", 5, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmFy", (const u8 *)"foobar", 6, false, BASE64_STD);
+	expect_decode_ok(test, "TWFu", (const u8 *)"Man", 3, false, BASE64_STD);
+	expect_decode_ok(test, "SGVsbG8sIHdvcmxkIQ", (const u8 *)"Hello, world!", 13,
+			 false, BASE64_STD);
+	expect_decode_ok(test, "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo",
+			 (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26, false, BASE64_STD);
+	expect_decode_ok(test, "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo",
+			 (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26, false, BASE64_STD);
+	expect_decode_ok(test, "MDEyMzQ1Njc4OSsv", (const u8 *)"0123456789+/", 12,
+			 false, BASE64_STD);
+
+	/* Error cases */
+	expect_decode_err(test, "Zg=!", 4, false, BASE64_STD);
+	expect_decode_err(test, "Zm$=", 4, false, BASE64_STD);
+	expect_decode_err(test, "Z===", 4, false, BASE64_STD);
+	expect_decode_err(test, "Zg=", 3, false, BASE64_STD);
+	expect_decode_err(test, "Zm9v====", 8, false, BASE64_STD);
+	expect_decode_err(test, "Zm==v", 4, false, BASE64_STD);
+
+	{
+		char with_nul[4] = { 'Z', 'g', '\0', '=' };
+
+		expect_decode_err(test, with_nul, 4, false, BASE64_STD);
+	}
+}
+
+/* ---------- Variant tests (URLSAFE / IMAP) ---------- */
+static void base64_variant_tests(struct kunit *test)
+{
+	const u8 sample1[] = { 0x00, 0xfb, 0xff, 0x7f, 0x80 };
+	char std_buf[128], url_buf[128], imap_buf[128];
+	u8 back[128];
+	int n_std, n_url, n_imap, m;
+	int i;
+
+	n_std = base64_encode(sample1, sizeof(sample1), std_buf, false, BASE64_STD);
+	n_url = base64_encode(sample1, sizeof(sample1), url_buf, false, BASE64_URLSAFE);
+	std_buf[n_std] = '\0';
+	url_buf[n_url] = '\0';
+
+	for (i = 0; i < n_std; i++) {
+		if (std_buf[i] == '+')
+			std_buf[i] = '-';
+		else if (std_buf[i] == '/')
+			std_buf[i] = '_';
+	}
+	KUNIT_EXPECT_STREQ(test, std_buf, url_buf);
+
+	m = base64_decode(url_buf, n_url, back, false, BASE64_URLSAFE);
+	KUNIT_EXPECT_EQ(test, m, (int)sizeof(sample1));
+	KUNIT_EXPECT_MEMEQ(test, back, sample1, sizeof(sample1));
+
+	n_std  = base64_encode(sample1, sizeof(sample1), std_buf, false, BASE64_STD);
+	n_imap = base64_encode(sample1, sizeof(sample1), imap_buf, false, BASE64_IMAP);
+	std_buf[n_std]   = '\0';
+	imap_buf[n_imap] = '\0';
+
+	for (i = 0; i < n_std; i++)
+		if (std_buf[i] == '/')
+			std_buf[i] = ',';
+	KUNIT_EXPECT_STREQ(test, std_buf, imap_buf);
+
+	m = base64_decode(imap_buf, n_imap, back, false, BASE64_IMAP);
+	KUNIT_EXPECT_EQ(test, m, (int)sizeof(sample1));
+	KUNIT_EXPECT_MEMEQ(test, back, sample1, sizeof(sample1));
+
+	{
+		const char *bad = "Zg==";
+		u8 tmp[8];
+
+		m = base64_decode(bad, strlen(bad), tmp, false, BASE64_URLSAFE);
+		KUNIT_EXPECT_EQ(test, m, -1);
+
+		m = base64_decode(bad, strlen(bad), tmp, false, BASE64_IMAP);
+		KUNIT_EXPECT_EQ(test, m, -1);
+	}
+}
+
+/* ---------- Test registration ---------- */
+static struct kunit_case base64_test_cases[] = {
+	KUNIT_CASE(base64_performance_tests),
+	KUNIT_CASE(base64_std_encode_tests),
+	KUNIT_CASE(base64_std_decode_tests),
+	KUNIT_CASE(base64_variant_tests),
+	{}
+};
+
+static struct kunit_suite base64_test_suite = {
+	.name = "base64",
+	.test_cases = base64_test_cases,
+};
+
+kunit_test_suite(base64_test_suite);
+
+MODULE_AUTHOR("Guan-Chun Wu <409411716@gms.tku.edu.tw>");
+MODULE_DESCRIPTION("KUnit tests for Base64 encoding/decoding, including performance checks");
+MODULE_LICENSE("GPL");