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, 152 insertions, 0 deletions

diff --git a/drivers/firewire/self-id-sequence-helper-test.c b/drivers/firewire/self-id-sequence-helper-test.c
new file mode 100644
index 000000000..eed7a2294
--- /dev/null
+++ b/drivers/firewire/self-id-sequence-helper-test.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// self-id-sequence-helper-test.c - An application of Kunit to test helpers of self ID sequence.
+//
+// Copyright (c) 2024 Takashi Sakamoto
+
+#include <kunit/test.h>
+
+#include "phy-packet-definitions.h"
+
+static void test_self_id_sequence_enumerator_valid(struct kunit *test)
+{
+	static const u32 valid_sequences[] = {
+		0x00000000,
+		0x00000001, 0x00800000,
+		0x00000001, 0x00800001, 0x00900000,
+		0x00000000,
+	};
+	struct self_id_sequence_enumerator enumerator;
+	const u32 *entry;
+	unsigned int quadlet_count;
+
+	enumerator.cursor = valid_sequences;
+	enumerator.quadlet_count = ARRAY_SIZE(valid_sequences);
+
+	entry = self_id_sequence_enumerator_next(&enumerator, &quadlet_count);
+	KUNIT_EXPECT_PTR_EQ(test, entry, &valid_sequences[0]);
+	KUNIT_EXPECT_EQ(test, quadlet_count, 1);
+	KUNIT_EXPECT_EQ(test, enumerator.quadlet_count, 6);
+
+	entry = self_id_sequence_enumerator_next(&enumerator, &quadlet_count);
+	KUNIT_EXPECT_PTR_EQ(test, entry, &valid_sequences[1]);
+	KUNIT_EXPECT_EQ(test, quadlet_count, 2);
+	KUNIT_EXPECT_EQ(test, enumerator.quadlet_count, 4);
+
+	entry = self_id_sequence_enumerator_next(&enumerator, &quadlet_count);
+	KUNIT_EXPECT_PTR_EQ(test, entry, &valid_sequences[3]);
+	KUNIT_EXPECT_EQ(test, quadlet_count, 3);
+	KUNIT_EXPECT_EQ(test, enumerator.quadlet_count, 1);
+
+	entry = self_id_sequence_enumerator_next(&enumerator, &quadlet_count);
+	KUNIT_EXPECT_PTR_EQ(test, entry, &valid_sequences[6]);
+	KUNIT_EXPECT_EQ(test, quadlet_count, 1);
+	KUNIT_EXPECT_EQ(test, enumerator.quadlet_count, 0);
+
+	entry = self_id_sequence_enumerator_next(&enumerator, &quadlet_count);
+	KUNIT_EXPECT_EQ(test, PTR_ERR(entry), -ENODATA);
+}
+
+static void test_self_id_sequence_enumerator_invalid(struct kunit *test)
+{
+	static const u32 invalid_sequences[] = {
+		0x00000001,
+	};
+	struct self_id_sequence_enumerator enumerator;
+	const u32 *entry;
+	unsigned int count;
+
+	enumerator.cursor = invalid_sequences;
+	enumerator.quadlet_count = ARRAY_SIZE(invalid_sequences);
+
+	entry = self_id_sequence_enumerator_next(&enumerator, &count);
+	KUNIT_EXPECT_EQ(test, PTR_ERR(entry), -EPROTO);
+}
+
+static void test_self_id_sequence_get_port_status(struct kunit *test)
+{
+	static const u32 expected[] = {
+		0x000000e5,
+		0x00839e79,
+		0x0091e79d,
+		0x00a279e4,
+	};
+	u32 quadlets [] = {
+		0x00000001,
+		0x00800001,
+		0x00900001,
+		0x00a00000,
+	};
+	enum phy_packet_self_id_port_status port_status[28];
+	unsigned int port_capacity;
+	unsigned int port_index;
+
+	KUNIT_ASSERT_EQ(test, ARRAY_SIZE(expected), ARRAY_SIZE(quadlets));
+
+	// With an extra port.
+	port_capacity = self_id_sequence_get_port_capacity(ARRAY_SIZE(expected)) + 1;
+	KUNIT_ASSERT_EQ(test, port_capacity, ARRAY_SIZE(port_status));
+
+	for (port_index = 0; port_index < port_capacity; ++port_index) {
+		port_status[port_index] =
+			self_id_sequence_get_port_status(expected, ARRAY_SIZE(expected), port_index);
+		self_id_sequence_set_port_status(quadlets, ARRAY_SIZE(quadlets), port_index,
+						 port_status[port_index]);
+	}
+
+	// Self ID zero.
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[0]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[1]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[2]);
+
+	// Self ID one.
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[3]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[4]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[5]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[6]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[7]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[8]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[9]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[10]);
+
+	// Self ID two.
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[11]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[12]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[13]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[14]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[15]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[16]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[17]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[18]);
+
+	// Self ID three.
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[19]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[20]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[21]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[22]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[23]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_CHILD, port_status[24]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_PARENT, port_status[25]);
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NCONN, port_status[26]);
+
+	// Our of order.
+	KUNIT_EXPECT_EQ(test, PHY_PACKET_SELF_ID_PORT_STATUS_NONE, port_status[27]);
+
+	KUNIT_EXPECT_MEMEQ(test, quadlets, expected, sizeof(expected));
+}
+
+static struct kunit_case self_id_sequence_helper_test_cases[] = {
+	KUNIT_CASE(test_self_id_sequence_enumerator_valid),
+	KUNIT_CASE(test_self_id_sequence_enumerator_invalid),
+	KUNIT_CASE(test_self_id_sequence_get_port_status),
+	{}
+};
+
+static struct kunit_suite self_id_sequence_helper_test_suite = {
+	.name = "self-id-sequence-helper",
+	.test_cases = self_id_sequence_helper_test_cases,
+};
+kunit_test_suite(self_id_sequence_helper_test_suite);
+
+MODULE_DESCRIPTION("Unit test suite for helpers of self ID sequence");
+MODULE_LICENSE("GPL");