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/drivers/input/joystick/interact.c b/drivers/input/joystick/interact.c
new file mode 100644
index 000000000..507cec36b
--- /dev/null
+++ b/drivers/input/joystick/interact.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (c) 2001 Vojtech Pavlik
+ *
+ *  Based on the work of:
+ *	Toby Deshane
+ */
+
+/*
+ * InterAct digital gamepad/joystick driver for Linux
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/gameport.h>
+#include <linux/input.h>
+#include <linux/jiffies.h>
+
+#define DRIVER_DESC	"InterAct digital joystick driver"
+
+MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+#define INTERACT_MAX_START	600	/* 400 us */
+#define INTERACT_MAX_STROBE	60	/* 40 us */
+#define INTERACT_MAX_LENGTH	32	/* 32 bits */
+
+#define INTERACT_TYPE_HHFX	0	/* HammerHead/FX */
+#define INTERACT_TYPE_PP8D	1	/* ProPad 8 */
+
+struct interact {
+	struct gameport *gameport;
+	struct input_dev *dev;
+	int bads;
+	int reads;
+	unsigned char type;
+	unsigned char length;
+	char phys[32];
+};
+
+static short interact_abs_hhfx[] =
+	{ ABS_RX, ABS_RY, ABS_X, ABS_Y, ABS_HAT0X, ABS_HAT0Y, -1 };
+static short interact_abs_pp8d[] =
+	{ ABS_X, ABS_Y, -1 };
+
+static short interact_btn_hhfx[] =
+	{ BTN_TR, BTN_X, BTN_Y, BTN_Z, BTN_A, BTN_B, BTN_C, BTN_TL, BTN_TL2, BTN_TR2, BTN_MODE, BTN_SELECT, -1 };
+static short interact_btn_pp8d[] =
+	{ BTN_C, BTN_TL, BTN_TR, BTN_A, BTN_B, BTN_Y, BTN_Z, BTN_X, -1 };
+
+struct interact_type {
+	int id;
+	short *abs;
+	short *btn;
+	char *name;
+	unsigned char length;
+	unsigned char b8;
+};
+
+static struct interact_type interact_type[] = {
+	{ 0x6202, interact_abs_hhfx, interact_btn_hhfx, "InterAct HammerHead/FX",    32, 4 },
+	{ 0x53f8, interact_abs_pp8d, interact_btn_pp8d, "InterAct ProPad 8 Digital", 16, 0 },
+	{ 0 }};
+
+/*
+ * interact_read_packet() reads and InterAct joystick data.
+ */
+
+static int interact_read_packet(struct gameport *gameport, int length, u32 *data)
+{
+	unsigned long flags;
+	unsigned char u, v;
+	unsigned int t, s;
+	int i;
+
+	i = 0;
+	data[0] = data[1] = data[2] = 0;
+	t = gameport_time(gameport, INTERACT_MAX_START);
+	s = gameport_time(gameport, INTERACT_MAX_STROBE);
+
+	local_irq_save(flags);
+	gameport_trigger(gameport);
+	v = gameport_read(gameport);
+
+	while (t > 0 && i < length) {
+		t--;
+		u = v; v = gameport_read(gameport);
+		if (v & ~u & 0x40) {
+			data[0] = (data[0] << 1) | ((v >> 4) & 1);
+			data[1] = (data[1] << 1) | ((v >> 5) & 1);
+			data[2] = (data[2] << 1) | ((v >> 7) & 1);
+			i++;
+			t = s;
+		}
+	}
+
+	local_irq_restore(flags);
+
+	return i;
+}
+
+/*
+ * interact_poll() reads and analyzes InterAct joystick data.
+ */
+
+static void interact_poll(struct gameport *gameport)
+{
+	struct interact *interact = gameport_get_drvdata(gameport);
+	struct input_dev *dev = interact->dev;
+	u32 data[3];
+	int i;
+
+	interact->reads++;
+
+	if (interact_read_packet(interact->gameport, interact->length, data) < interact->length) {
+		interact->bads++;
+	} else {
+
+		for (i = 0; i < 3; i++)
+			data[i] <<= INTERACT_MAX_LENGTH - interact->length;
+
+		switch (interact->type) {
+
+			case INTERACT_TYPE_HHFX:
+
+				for (i = 0; i < 4; i++)
+					input_report_abs(dev, interact_abs_hhfx[i], (data[i & 1] >> ((i >> 1) << 3)) & 0xff);
+
+				for (i = 0; i < 2; i++)
+					input_report_abs(dev, ABS_HAT0Y - i,
+						((data[1] >> ((i << 1) + 17)) & 1)  - ((data[1] >> ((i << 1) + 16)) & 1));
+
+				for (i = 0; i < 8; i++)
+					input_report_key(dev, interact_btn_hhfx[i], (data[0] >> (i + 16)) & 1);
+
+				for (i = 0; i < 4; i++)
+					input_report_key(dev, interact_btn_hhfx[i + 8], (data[1] >> (i + 20)) & 1);
+
+				break;
+
+			case INTERACT_TYPE_PP8D:
+
+				for (i = 0; i < 2; i++)
+					input_report_abs(dev, interact_abs_pp8d[i],
+						((data[0] >> ((i << 1) + 20)) & 1)  - ((data[0] >> ((i << 1) + 21)) & 1));
+
+				for (i = 0; i < 8; i++)
+					input_report_key(dev, interact_btn_pp8d[i], (data[1] >> (i + 16)) & 1);
+
+				break;
+		}
+	}
+
+	input_sync(dev);
+}
+
+/*
+ * interact_open() is a callback from the input open routine.
+ */
+
+static int interact_open(struct input_dev *dev)
+{
+	struct interact *interact = input_get_drvdata(dev);
+
+	gameport_start_polling(interact->gameport);
+	return 0;
+}
+
+/*
+ * interact_close() is a callback from the input close routine.
+ */
+
+static void interact_close(struct input_dev *dev)
+{
+	struct interact *interact = input_get_drvdata(dev);
+
+	gameport_stop_polling(interact->gameport);
+}
+
+/*
+ * interact_connect() probes for InterAct joysticks.
+ */
+
+static int interact_connect(struct gameport *gameport, struct gameport_driver *drv)
+{
+	struct interact *interact;
+	struct input_dev *input_dev;
+	__u32 data[3];
+	int i, t;
+	int err;
+
+	interact = kzalloc_obj(*interact);
+	input_dev = input_allocate_device();
+	if (!interact || !input_dev) {
+		err = -ENOMEM;
+		goto fail1;
+	}
+
+	interact->gameport = gameport;
+	interact->dev = input_dev;
+
+	gameport_set_drvdata(gameport, interact);
+
+	err = gameport_open(gameport, drv, GAMEPORT_MODE_RAW);
+	if (err)
+		goto fail1;
+
+	i = interact_read_packet(gameport, INTERACT_MAX_LENGTH * 2, data);
+
+	if (i != 32 || (data[0] >> 24) != 0x0c || (data[1] >> 24) != 0x02) {
+		err = -ENODEV;
+		goto fail2;
+	}
+
+	for (i = 0; interact_type[i].length; i++)
+		if (interact_type[i].id == (data[2] >> 16))
+			break;
+
+	if (!interact_type[i].length) {
+		printk(KERN_WARNING "interact.c: Unknown joystick on %s. [len %d d0 %08x d1 %08x i2 %08x]\n",
+			gameport->phys, i, data[0], data[1], data[2]);
+		err = -ENODEV;
+		goto fail2;
+	}
+
+	gameport_set_poll_handler(gameport, interact_poll);
+	gameport_set_poll_interval(gameport, 20);
+
+	snprintf(interact->phys, sizeof(interact->phys), "%s/input0", gameport->phys);
+
+	interact->type = i;
+	interact->length = interact_type[i].length;
+
+	input_dev->name = interact_type[i].name;
+	input_dev->phys = interact->phys;
+	input_dev->id.bustype = BUS_GAMEPORT;
+	input_dev->id.vendor = GAMEPORT_ID_VENDOR_INTERACT;
+	input_dev->id.product = interact_type[i].id;
+	input_dev->id.version = 0x0100;
+	input_dev->dev.parent = &gameport->dev;
+
+	input_set_drvdata(input_dev, interact);
+
+	input_dev->open = interact_open;
+	input_dev->close = interact_close;
+
+	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+
+	for (i = 0; (t = interact_type[interact->type].abs[i]) >= 0; i++) {
+		if (i < interact_type[interact->type].b8)
+			input_set_abs_params(input_dev, t, 0, 255, 0, 0);
+		else
+			input_set_abs_params(input_dev, t, -1, 1, 0, 0);
+	}
+
+	for (i = 0; (t = interact_type[interact->type].btn[i]) >= 0; i++)
+		__set_bit(t, input_dev->keybit);
+
+	err = input_register_device(interact->dev);
+	if (err)
+		goto fail2;
+
+	return 0;
+
+fail2:	gameport_close(gameport);
+fail1:  gameport_set_drvdata(gameport, NULL);
+	input_free_device(input_dev);
+	kfree(interact);
+	return err;
+}
+
+static void interact_disconnect(struct gameport *gameport)
+{
+	struct interact *interact = gameport_get_drvdata(gameport);
+
+	input_unregister_device(interact->dev);
+	gameport_close(gameport);
+	gameport_set_drvdata(gameport, NULL);
+	kfree(interact);
+}
+
+static struct gameport_driver interact_drv = {
+	.driver		= {
+		.name	= "interact",
+	},
+	.description	= DRIVER_DESC,
+	.connect	= interact_connect,
+	.disconnect	= interact_disconnect,
+};
+
+module_gameport_driver(interact_drv);