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, 175 insertions, 0 deletions

diff --git a/lib/tests/shdi3_kunit.c b/lib/tests/shdi3_kunit.c
new file mode 100644
index 000000000..44f65e665
--- /dev/null
+++ b/lib/tests/shdi3_kunit.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR Apache-2.0
+/*
+ * Test cases for __ashldi3(), __ashrdi3(), and __lshrdi3().
+ */
+
+#include <linux/array_size.h>
+#include <linux/module.h>
+#include <linux/libgcc.h>
+#include <kunit/test.h>
+
+struct shdi3_test_entry {
+	long long input;
+	int shift;
+	long long result;
+};
+
+static const struct shdi3_test_entry ashldi3_testdata[] = {
+	/* https://github.com/llvm/llvm-project/compiler-rt/test/builtins/Unit/ashldi3_test.c */
+	{ 0x0123456789ABCDEFLL, 0, 0x123456789ABCDEFLL },
+	{ 0x0123456789ABCDEFLL, 1, 0x2468ACF13579BDELL },
+	{ 0x0123456789ABCDEFLL, 2, 0x48D159E26AF37BCLL },
+	{ 0x0123456789ABCDEFLL, 3, 0x91A2B3C4D5E6F78LL },
+	{ 0x0123456789ABCDEFLL, 4, 0x123456789ABCDEF0LL },
+	{ 0x0123456789ABCDEFLL, 28, 0x789ABCDEF0000000LL },
+	{ 0x0123456789ABCDEFLL, 29, 0xF13579BDE0000000LL },
+	{ 0x0123456789ABCDEFLL, 30, 0xE26AF37BC0000000LL },
+	{ 0x0123456789ABCDEFLL, 31, 0xC4D5E6F780000000LL },
+	{ 0x0123456789ABCDEFLL, 32, 0x89ABCDEF00000000LL },
+	{ 0x0123456789ABCDEFLL, 33, 0x13579BDE00000000LL },
+	{ 0x0123456789ABCDEFLL, 34, 0x26AF37BC00000000LL },
+	{ 0x0123456789ABCDEFLL, 35, 0x4D5E6F7800000000LL },
+	{ 0x0123456789ABCDEFLL, 36, 0x9ABCDEF000000000LL },
+	{ 0x0123456789ABCDEFLL, 60, 0xF000000000000000LL },
+	{ 0x0123456789ABCDEFLL, 61, 0xE000000000000000LL },
+	{ 0x0123456789ABCDEFLL, 62, 0xC000000000000000LL },
+	{ 0x0123456789ABCDEFLL, 63, 0x8000000000000000LL },
+};
+
+static void shdi3_test_ashldi3(struct kunit *test)
+{
+	const struct shdi3_test_entry *e;
+	long long ret;
+
+	for (e = ashldi3_testdata;
+	     e < ashldi3_testdata + ARRAY_SIZE(ashldi3_testdata); e++) {
+		ret = __ashldi3(e->input, e->shift);
+		KUNIT_EXPECT_EQ_MSG(test, ret, e->result,
+				    "    when evaluating __ashldi3(%lld, %d)",
+				    e->input, e->shift);
+	}
+}
+
+static const struct shdi3_test_entry ashrdi3_testdata[] = {
+	/* https://github.com/llvm/llvm-project/compiler-rt/test/builtins/Unit/ashrdi3_test.c */
+	{ 0x0123456789ABCDEFLL, 0, 0x123456789ABCDEFLL },
+	{ 0x0123456789ABCDEFLL, 1, 0x91A2B3C4D5E6F7LL },
+	{ 0x0123456789ABCDEFLL, 2, 0x48D159E26AF37BLL },
+	{ 0x0123456789ABCDEFLL, 3, 0x2468ACF13579BDLL },
+	{ 0x0123456789ABCDEFLL, 4, 0x123456789ABCDELL },
+	{ 0x0123456789ABCDEFLL, 28, 0x12345678LL },
+	{ 0x0123456789ABCDEFLL, 29, 0x91A2B3CLL },
+	{ 0x0123456789ABCDEFLL, 30, 0x48D159ELL },
+	{ 0x0123456789ABCDEFLL, 31, 0x2468ACFLL },
+	{ 0x0123456789ABCDEFLL, 32, 0x1234567LL },
+	{ 0x0123456789ABCDEFLL, 33, 0x91A2B3LL },
+	{ 0x0123456789ABCDEFLL, 34, 0x48D159LL },
+	{ 0x0123456789ABCDEFLL, 35, 0x2468ACLL },
+	{ 0x0123456789ABCDEFLL, 36, 0x123456LL },
+	{ 0x0123456789ABCDEFLL, 60, 0 },
+	{ 0x0123456789ABCDEFLL, 61, 0 },
+	{ 0x0123456789ABCDEFLL, 62, 0 },
+	{ 0x0123456789ABCDEFLL, 63, 0 },
+	{ 0xFEDCBA9876543210LL, 0, 0xFEDCBA9876543210LL },
+	{ 0xFEDCBA9876543210LL, 1, 0xFF6E5D4C3B2A1908LL },
+	{ 0xFEDCBA9876543210LL, 2, 0xFFB72EA61D950C84LL },
+	{ 0xFEDCBA9876543210LL, 3, 0xFFDB97530ECA8642LL },
+	{ 0xFEDCBA9876543210LL, 4, 0xFFEDCBA987654321LL },
+	{ 0xFEDCBA9876543210LL, 28, 0xFFFFFFFFEDCBA987LL },
+	{ 0xFEDCBA9876543210LL, 29, 0xFFFFFFFFF6E5D4C3LL },
+	{ 0xFEDCBA9876543210LL, 30, 0xFFFFFFFFFB72EA61LL },
+	{ 0xFEDCBA9876543210LL, 31, 0xFFFFFFFFFDB97530LL },
+	{ 0xFEDCBA9876543210LL, 32, 0xFFFFFFFFFEDCBA98LL },
+	{ 0xFEDCBA9876543210LL, 33, 0xFFFFFFFFFF6E5D4CLL },
+	{ 0xFEDCBA9876543210LL, 34, 0xFFFFFFFFFFB72EA6LL },
+	{ 0xFEDCBA9876543210LL, 35, 0xFFFFFFFFFFDB9753LL },
+	{ 0xFEDCBA9876543210LL, 36, 0xFFFFFFFFFFEDCBA9LL },
+	{ 0xAEDCBA9876543210LL, 60, 0xFFFFFFFFFFFFFFFALL },
+	{ 0xAEDCBA9876543210LL, 61, 0xFFFFFFFFFFFFFFFDLL },
+	{ 0xAEDCBA9876543210LL, 62, 0xFFFFFFFFFFFFFFFELL },
+	{ 0xAEDCBA9876543210LL, 63, 0xFFFFFFFFFFFFFFFFLL },
+};
+
+static void shdi3_test_ashrdi3(struct kunit *test)
+{
+	const struct shdi3_test_entry *e;
+	long long ret;
+
+	for (e = ashrdi3_testdata;
+	     e < ashrdi3_testdata + ARRAY_SIZE(ashrdi3_testdata); e++) {
+		ret = __ashrdi3(e->input, e->shift);
+		KUNIT_EXPECT_EQ_MSG(test, ret, e->result,
+				    "    when evaluating __ashrdi3(%lld, %d)",
+				    e->input, e->shift);
+	}
+}
+
+static const struct shdi3_test_entry lshrdi3_testdata[] = {
+	/* https://github.com/llvm/llvm-project/compiler-rt/test/builtins/Unit/lshrdi3_test.c */
+	{ 0x0123456789ABCDEFLL, 0, 0x123456789ABCDEFLL },
+	{ 0x0123456789ABCDEFLL, 1, 0x91A2B3C4D5E6F7LL },
+	{ 0x0123456789ABCDEFLL, 2, 0x48D159E26AF37BLL },
+	{ 0x0123456789ABCDEFLL, 3, 0x2468ACF13579BDLL },
+	{ 0x0123456789ABCDEFLL, 4, 0x123456789ABCDELL },
+	{ 0x0123456789ABCDEFLL, 28, 0x12345678LL },
+	{ 0x0123456789ABCDEFLL, 29, 0x91A2B3CLL },
+	{ 0x0123456789ABCDEFLL, 30, 0x48D159ELL },
+	{ 0x0123456789ABCDEFLL, 31, 0x2468ACFLL },
+	{ 0x0123456789ABCDEFLL, 32, 0x1234567LL },
+	{ 0x0123456789ABCDEFLL, 33, 0x91A2B3LL },
+	{ 0x0123456789ABCDEFLL, 34, 0x48D159LL },
+	{ 0x0123456789ABCDEFLL, 35, 0x2468ACLL },
+	{ 0x0123456789ABCDEFLL, 36, 0x123456LL },
+	{ 0x0123456789ABCDEFLL, 60, 0 },
+	{ 0x0123456789ABCDEFLL, 61, 0 },
+	{ 0x0123456789ABCDEFLL, 62, 0 },
+	{ 0x0123456789ABCDEFLL, 63, 0 },
+	{ 0xFEDCBA9876543210LL, 0, 0xFEDCBA9876543210LL },
+	{ 0xFEDCBA9876543210LL, 1, 0x7F6E5D4C3B2A1908LL },
+	{ 0xFEDCBA9876543210LL, 2, 0x3FB72EA61D950C84LL },
+	{ 0xFEDCBA9876543210LL, 3, 0x1FDB97530ECA8642LL },
+	{ 0xFEDCBA9876543210LL, 4, 0xFEDCBA987654321LL },
+	{ 0xFEDCBA9876543210LL, 28, 0xFEDCBA987LL },
+	{ 0xFEDCBA9876543210LL, 29, 0x7F6E5D4C3LL },
+	{ 0xFEDCBA9876543210LL, 30, 0x3FB72EA61LL },
+	{ 0xFEDCBA9876543210LL, 31, 0x1FDB97530LL },
+	{ 0xFEDCBA9876543210LL, 32, 0xFEDCBA98LL },
+	{ 0xFEDCBA9876543210LL, 33, 0x7F6E5D4CLL },
+	{ 0xFEDCBA9876543210LL, 34, 0x3FB72EA6LL },
+	{ 0xFEDCBA9876543210LL, 35, 0x1FDB9753LL },
+	{ 0xFEDCBA9876543210LL, 36, 0xFEDCBA9LL },
+	{ 0xAEDCBA9876543210LL, 60, 0xALL },
+	{ 0xAEDCBA9876543210LL, 61, 0x5LL },
+	{ 0xAEDCBA9876543210LL, 62, 0x2LL },
+	{ 0xAEDCBA9876543210LL, 63, 0x1LL },
+};
+
+static void shdi3_test_lshrdi3(struct kunit *test)
+{
+	const struct shdi3_test_entry *e;
+	long long ret;
+
+	for (e = lshrdi3_testdata;
+	     e < lshrdi3_testdata + ARRAY_SIZE(lshrdi3_testdata); e++) {
+		ret = __lshrdi3(e->input, e->shift);
+		KUNIT_EXPECT_EQ_MSG(test, ret, e->result,
+				    "    when evaluating __lshrdi3(%lld, %d)",
+				    e->input, e->shift);
+	}
+}
+
+static struct kunit_case shdi3_test_cases[] = {
+	KUNIT_CASE(shdi3_test_ashldi3),
+	KUNIT_CASE(shdi3_test_ashrdi3),
+	KUNIT_CASE(shdi3_test_lshrdi3),
+	{}
+};
+
+static struct kunit_suite shdi3_test_suite = {
+	.name = "shdi3",
+	.test_cases = shdi3_test_cases,
+};
+kunit_test_suite(shdi3_test_suite);
+
+MODULE_DESCRIPTION("Test cases for __ashldi3(), __ashrdi3(), and __lshrdi3()");
+MODULE_LICENSE("GPL");