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, 253 insertions, 0 deletions

diff --git a/drivers/firewire/device-attribute-test.c b/drivers/firewire/device-attribute-test.c
new file mode 100644
index 000000000..97478a96d
--- /dev/null
+++ b/drivers/firewire/device-attribute-test.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// device-attribute-test.c - An application of Kunit to test implementation for device attributes.
+//
+// Copyright (c) 2023 Takashi Sakamoto
+//
+// This file can not be built independently since it is intentionally included in core-device.c.
+
+#include <kunit/test.h>
+
+// Configuration ROM for AV/C Devices 1.0 (Dec. 12, 2000, 1394 Trading Association)
+// Annex C:Configuration ROM example(informative)
+// C.1 Simple AV/C device
+//
+// Copied from the documentation.
+static const u32 simple_avc_config_rom[] = {
+	0x0404eabf,
+	0x31333934,
+	0xe0646102,
+	0xffffffff,
+	0xffffffff,
+	0x00063287, // root directory.
+	0x03ffffff,
+	0x8100000a,
+	0x17ffffff,
+	0x8100000e,
+	0x0c0083c0,
+	0xd1000001,
+	0x0004442d, // unit 0 directory.
+	0x1200a02d,
+	0x13010001,
+	0x17ffffff,
+	0x81000007,
+	0x0005c915, // leaf for textual descriptor.
+	0x00000000,
+	0x00000000,
+	0x56656e64,
+	0x6f72204e,
+	0x616d6500,
+	0x00057f16, // leaf for textual descriptor.
+	0x00000000,
+	0x00000000,
+	0x4d6f6465,
+	0x6c204e61,
+	0x6d650000,
+};
+
+// Ibid.
+// Annex A:Consideration for configuration ROM reader design (informative)
+// A.1 Vendor directory
+//
+// Written by hand.
+static const u32 legacy_avc_config_rom[] = {
+	0x04199fe7,
+	0x31333934,
+	0xe0644000,
+	0x00112233,
+	0x44556677,
+	0x0005dace, // root directory.
+	0x03012345,
+	0x0c0083c0,
+	0x8d000009,
+	0xd1000002,
+	0xc3000004,
+	0x0002e107, // unit 0 directory.
+	0x12abcdef,
+	0x13543210,
+	0x0002cb73, // vendor directory.
+	0x17fedcba,
+	0x81000004,
+	0x00026dc1, // leaf for EUI-64.
+	0x00112233,
+	0x44556677,
+	0x00050e84, // leaf for textual descriptor.
+	0x00000000,
+	0x00000000,
+	0x41424344,
+	0x45464748,
+	0x494a0000,
+};
+
+static void device_attr_simple_avc(struct kunit *test)
+{
+	static const struct fw_device node = {
+		.device = {
+			.type = &fw_device_type,
+		},
+		.config_rom = simple_avc_config_rom,
+		.config_rom_length = sizeof(simple_avc_config_rom),
+	};
+	static const struct fw_unit unit0 = {
+		.device = {
+			.type = &fw_unit_type,
+			.parent = (struct device *)&node.device,
+		},
+		.directory = &simple_avc_config_rom[12],
+	};
+	struct device *node_dev = (struct device *)&node.device;
+	struct device *unit0_dev = (struct device *)&unit0.device;
+	static const int unit0_expected_ids[] = {0x00ffffff, 0x00ffffff, 0x0000a02d, 0x00010001};
+	char *buf = kunit_kzalloc(test, PAGE_SIZE, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+	int ids[4] = {0, 0, 0, 0};
+
+	// Ensure associations for node and unit devices.
+
+	KUNIT_ASSERT_TRUE(test, is_fw_device(node_dev));
+	KUNIT_ASSERT_FALSE(test, is_fw_unit(node_dev));
+	KUNIT_ASSERT_PTR_EQ(test, fw_device(node_dev), &node);
+
+	KUNIT_ASSERT_FALSE(test, is_fw_device(unit0_dev));
+	KUNIT_ASSERT_TRUE(test, is_fw_unit(unit0_dev));
+	KUNIT_ASSERT_PTR_EQ(test, fw_parent_device((&unit0)), &node);
+	KUNIT_ASSERT_PTR_EQ(test, fw_unit(unit0_dev), &unit0);
+
+	// For entries in root directory.
+
+	// Vendor immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(node_dev, &config_rom_attributes[0].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0xffffff\n");
+
+	// Model immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(node_dev, &config_rom_attributes[4].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0xffffff\n");
+
+	// Descriptor leaf entry for vendor is found.
+	KUNIT_EXPECT_GT(test, show_text_leaf(node_dev, &config_rom_attributes[5].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "Vendor Name\n");
+
+	// Descriptor leaf entry for model is found.
+	KUNIT_EXPECT_GT(test, show_text_leaf(node_dev, &config_rom_attributes[6].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "Model Name\n");
+
+	// For entries in unit 0 directory.
+
+	// Vendor immediate entry is not found.
+	KUNIT_EXPECT_LT(test, show_immediate(unit0_dev, &config_rom_attributes[0].attr, buf), 0);
+
+	// Model immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(unit0_dev, &config_rom_attributes[4].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0xffffff\n");
+
+	// Descriptor leaf entry for vendor is not found.
+	KUNIT_EXPECT_LT(test, show_text_leaf(unit0_dev, &config_rom_attributes[5].attr, buf), 0);
+
+	// Descriptor leaf entry for model is found.
+	KUNIT_EXPECT_GT(test, show_text_leaf(unit0_dev, &config_rom_attributes[6].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "Model Name\n");
+
+	// Specifier_ID immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(unit0_dev, &config_rom_attributes[2].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0x00a02d\n");
+
+	// Version immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(unit0_dev, &config_rom_attributes[3].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0x010001\n");
+
+	kunit_kfree(test, buf);
+
+	get_modalias_ids(&unit0, ids);
+	KUNIT_EXPECT_MEMEQ(test, ids, unit0_expected_ids, sizeof(ids));
+}
+
+static void device_attr_legacy_avc(struct kunit *test)
+{
+	static const struct fw_device node = {
+		.device = {
+			.type = &fw_device_type,
+		},
+		.config_rom = legacy_avc_config_rom,
+		.config_rom_length = sizeof(legacy_avc_config_rom),
+	};
+	static const struct fw_unit unit0 = {
+		.device = {
+			.type = &fw_unit_type,
+			.parent = (struct device *)&node.device,
+		},
+		.directory = &legacy_avc_config_rom[11],
+	};
+	struct device *node_dev = (struct device *)&node.device;
+	struct device *unit0_dev = (struct device *)&unit0.device;
+	static const int unit0_expected_ids[] = {0x00012345, 0x00fedcba, 0x00abcdef, 0x00543210};
+	char *buf = kunit_kzalloc(test, PAGE_SIZE, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+	int ids[4] = {0, 0, 0, 0};
+
+	// Ensure associations for node and unit devices.
+
+	KUNIT_ASSERT_TRUE(test, is_fw_device(node_dev));
+	KUNIT_ASSERT_FALSE(test, is_fw_unit(node_dev));
+	KUNIT_ASSERT_PTR_EQ(test, fw_device((node_dev)), &node);
+
+	KUNIT_ASSERT_FALSE(test, is_fw_device(unit0_dev));
+	KUNIT_ASSERT_TRUE(test, is_fw_unit(unit0_dev));
+	KUNIT_ASSERT_PTR_EQ(test, fw_parent_device((&unit0)), &node);
+	KUNIT_ASSERT_PTR_EQ(test, fw_unit(unit0_dev), &unit0);
+
+	// For entries in root directory.
+
+	// Vendor immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(node_dev, &config_rom_attributes[0].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0x012345\n");
+
+	// Model immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(node_dev, &config_rom_attributes[4].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0xfedcba\n");
+
+	// Descriptor leaf entry for vendor is not found.
+	KUNIT_EXPECT_LT(test, show_text_leaf(node_dev, &config_rom_attributes[5].attr, buf), 0);
+
+	// Descriptor leaf entry for model is found.
+	KUNIT_EXPECT_GT(test, show_text_leaf(node_dev, &config_rom_attributes[6].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "ABCDEFGHIJ\n");
+
+	// For entries in unit 0 directory.
+
+	// Vendor immediate entry is not found.
+	KUNIT_EXPECT_LT(test, show_immediate(unit0_dev, &config_rom_attributes[0].attr, buf), 0);
+
+	// Model immediate entry is not found.
+	KUNIT_EXPECT_LT(test, show_immediate(unit0_dev, &config_rom_attributes[4].attr, buf), 0);
+
+	// Descriptor leaf entry for vendor is not found.
+	KUNIT_EXPECT_LT(test, show_text_leaf(unit0_dev, &config_rom_attributes[5].attr, buf), 0);
+
+	// Descriptor leaf entry for model is not found.
+	KUNIT_EXPECT_LT(test, show_text_leaf(unit0_dev, &config_rom_attributes[6].attr, buf), 0);
+
+	// Specifier_ID immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(unit0_dev, &config_rom_attributes[2].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0xabcdef\n");
+
+	// Version immediate entry is found.
+	KUNIT_EXPECT_GT(test, show_immediate(unit0_dev, &config_rom_attributes[3].attr, buf), 0);
+	KUNIT_EXPECT_STREQ(test, buf, "0x543210\n");
+
+	kunit_kfree(test, buf);
+
+	get_modalias_ids(&unit0, ids);
+	KUNIT_EXPECT_MEMEQ(test, ids, unit0_expected_ids, sizeof(ids));
+}
+
+static struct kunit_case device_attr_test_cases[] = {
+	KUNIT_CASE(device_attr_simple_avc),
+	KUNIT_CASE(device_attr_legacy_avc),
+	{}
+};
+
+static struct kunit_suite device_attr_test_suite = {
+	.name = "firewire-device-attribute",
+	.test_cases = device_attr_test_cases,
+};
+kunit_test_suite(device_attr_test_suite);