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, 532 insertions, 0 deletions

diff --git a/drivers/hid/hid-appletb-kbd.c b/drivers/hid/hid-appletb-kbd.c
new file mode 100644
index 000000000..5cc27066f
--- /dev/null
+++ b/drivers/hid/hid-appletb-kbd.c
@@ -0,0 +1,532 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Apple Touch Bar Keyboard Mode Driver
+ *
+ * Copyright (c) 2017-2018 Ronald Tschalär
+ * Copyright (c) 2022-2023 Kerem Karabay <kekrby@gmail.com>
+ * Copyright (c) 2024-2025 Aditya Garg <gargaditya08@live.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/hid.h>
+#include <linux/usb.h>
+#include <linux/input.h>
+#include <linux/sysfs.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/backlight.h>
+#include <linux/workqueue.h>
+#include <linux/input/sparse-keymap.h>
+
+#include "hid-ids.h"
+
+#define APPLETB_KBD_MODE_ESC	0
+#define APPLETB_KBD_MODE_FN	1
+#define APPLETB_KBD_MODE_SPCL	2
+#define APPLETB_KBD_MODE_OFF	3
+#define APPLETB_KBD_MODE_MAX	APPLETB_KBD_MODE_OFF
+
+#define APPLETB_DEVID_KEYBOARD	1
+#define APPLETB_DEVID_TRACKPAD	2
+
+#define HID_USAGE_MODE		0x00ff0004
+
+static int appletb_tb_def_mode = APPLETB_KBD_MODE_SPCL;
+module_param_named(mode, appletb_tb_def_mode, int, 0444);
+MODULE_PARM_DESC(mode, "Default touchbar mode:\n"
+			 "    0 - escape key only\n"
+			 "    1 - function-keys\n"
+			 "    [2] - special keys");
+
+static bool appletb_tb_fn_toggle = true;
+module_param_named(fntoggle, appletb_tb_fn_toggle, bool, 0644);
+MODULE_PARM_DESC(fntoggle, "Switch between Fn and media controls on pressing Fn key");
+
+static bool appletb_tb_autodim = true;
+module_param_named(autodim, appletb_tb_autodim, bool, 0644);
+MODULE_PARM_DESC(autodim, "Automatically dim and turn off the Touch Bar after some time");
+
+static int appletb_tb_dim_timeout = 60;
+module_param_named(dim_timeout, appletb_tb_dim_timeout, int, 0644);
+MODULE_PARM_DESC(dim_timeout, "Dim timeout in sec");
+
+static int appletb_tb_idle_timeout = 15;
+module_param_named(idle_timeout, appletb_tb_idle_timeout, int, 0644);
+MODULE_PARM_DESC(idle_timeout, "Idle timeout in sec");
+
+struct appletb_kbd {
+	struct hid_field *mode_field;
+	struct input_handler inp_handler;
+	struct input_handle kbd_handle;
+	struct input_handle tpd_handle;
+	struct backlight_device *backlight_dev;
+	struct delayed_work inactivity_work;
+	struct work_struct restore_brightness_work;
+	bool has_dimmed;
+	bool has_turned_off;
+	u8 saved_mode;
+	u8 current_mode;
+};
+
+static const struct key_entry appletb_kbd_keymap[] = {
+	{ KE_KEY, KEY_ESC, { KEY_ESC } },
+	{ KE_KEY, KEY_F1,  { KEY_BRIGHTNESSDOWN } },
+	{ KE_KEY, KEY_F2,  { KEY_BRIGHTNESSUP } },
+	{ KE_KEY, KEY_F3,  { KEY_RESERVED } },
+	{ KE_KEY, KEY_F4,  { KEY_RESERVED } },
+	{ KE_KEY, KEY_F5,  { KEY_KBDILLUMDOWN } },
+	{ KE_KEY, KEY_F6,  { KEY_KBDILLUMUP } },
+	{ KE_KEY, KEY_F7,  { KEY_PREVIOUSSONG } },
+	{ KE_KEY, KEY_F8,  { KEY_PLAYPAUSE } },
+	{ KE_KEY, KEY_F9,  { KEY_NEXTSONG } },
+	{ KE_KEY, KEY_F10, { KEY_MUTE } },
+	{ KE_KEY, KEY_F11, { KEY_VOLUMEDOWN } },
+	{ KE_KEY, KEY_F12, { KEY_VOLUMEUP } },
+	{ KE_END, 0 }
+};
+
+static int appletb_kbd_set_mode(struct appletb_kbd *kbd, u8 mode)
+{
+	struct hid_report *report = kbd->mode_field->report;
+	struct hid_device *hdev = report->device;
+	int ret;
+
+	ret = hid_hw_power(hdev, PM_HINT_FULLON);
+	if (ret) {
+		hid_err(hdev, "Device didn't resume (%pe)\n", ERR_PTR(ret));
+		return ret;
+	}
+
+	ret = hid_set_field(kbd->mode_field, 0, mode);
+	if (ret) {
+		hid_err(hdev, "Failed to set mode field to %u (%pe)\n", mode, ERR_PTR(ret));
+		goto power_normal;
+	}
+
+	hid_hw_request(hdev, report, HID_REQ_SET_REPORT);
+
+	kbd->current_mode = mode;
+
+power_normal:
+	hid_hw_power(hdev, PM_HINT_NORMAL);
+
+	return ret;
+}
+
+static ssize_t mode_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct appletb_kbd *kbd = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", kbd->current_mode);
+}
+
+static ssize_t mode_store(struct device *dev,
+			  struct device_attribute *attr,
+			  const char *buf, size_t size)
+{
+	struct appletb_kbd *kbd = dev_get_drvdata(dev);
+	u8 mode;
+	int ret;
+
+	ret = kstrtou8(buf, 0, &mode);
+	if (ret)
+		return ret;
+
+	if (mode > APPLETB_KBD_MODE_MAX)
+		return -EINVAL;
+
+	ret = appletb_kbd_set_mode(kbd, mode);
+
+	return ret < 0 ? ret : size;
+}
+static DEVICE_ATTR_RW(mode);
+
+static struct attribute *appletb_kbd_attrs[] = {
+	&dev_attr_mode.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(appletb_kbd);
+
+static int appletb_tb_key_to_slot(unsigned int code)
+{
+	switch (code) {
+	case KEY_ESC:
+		return 0;
+	case KEY_F1 ... KEY_F10:
+		return code - KEY_F1 + 1;
+	case KEY_F11 ... KEY_F12:
+		return code - KEY_F11 + 11;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static void appletb_inactivity_work(struct work_struct *work)
+{
+	struct appletb_kbd *kbd = container_of(to_delayed_work(work),
+					       struct appletb_kbd,
+					       inactivity_work);
+
+	if (kbd->backlight_dev && appletb_tb_autodim) {
+		if (!kbd->has_dimmed) {
+			backlight_device_set_brightness(kbd->backlight_dev, 1);
+			kbd->has_dimmed = true;
+			mod_delayed_work(system_dfl_wq, &kbd->inactivity_work,
+					 secs_to_jiffies(appletb_tb_idle_timeout));
+		} else if (!kbd->has_turned_off) {
+			backlight_device_set_brightness(kbd->backlight_dev, 0);
+			kbd->has_turned_off = true;
+		}
+	}
+}
+
+static void appletb_restore_brightness_work(struct work_struct *work)
+{
+	struct appletb_kbd *kbd = container_of(work, struct appletb_kbd,
+					       restore_brightness_work);
+
+	if (kbd->backlight_dev)
+		backlight_device_set_brightness(kbd->backlight_dev, 2);
+}
+
+static void reset_inactivity_timer(struct appletb_kbd *kbd)
+{
+	if (kbd->backlight_dev && appletb_tb_autodim) {
+		if (kbd->has_dimmed || kbd->has_turned_off) {
+			kbd->has_dimmed = false;
+			kbd->has_turned_off = false;
+			schedule_work(&kbd->restore_brightness_work);
+		}
+		mod_delayed_work(system_dfl_wq, &kbd->inactivity_work,
+				 secs_to_jiffies(appletb_tb_dim_timeout));
+	}
+}
+
+static int appletb_kbd_hid_event(struct hid_device *hdev, struct hid_field *field,
+				      struct hid_usage *usage, __s32 value)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+	struct key_entry *translation;
+	struct input_dev *input;
+	int slot;
+
+	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_KEYBOARD || usage->type != EV_KEY)
+		return 0;
+
+	input = field->hidinput->input;
+
+	/*
+	 * Skip non-touch-bar keys.
+	 *
+	 * Either the touch bar itself or usbhid generate a slew of key-down
+	 * events for all the meta keys. None of which we're at all interested
+	 * in.
+	 */
+	slot = appletb_tb_key_to_slot(usage->code);
+	if (slot < 0)
+		return 0;
+
+	reset_inactivity_timer(kbd);
+
+	translation = sparse_keymap_entry_from_scancode(input, usage->code);
+
+	if (translation && kbd->current_mode == APPLETB_KBD_MODE_SPCL) {
+		input_event(input, usage->type, translation->keycode, value);
+
+		return 1;
+	}
+
+	return kbd->current_mode == APPLETB_KBD_MODE_OFF;
+}
+
+static void appletb_kbd_inp_event(struct input_handle *handle, unsigned int type,
+			      unsigned int code, int value)
+{
+	struct appletb_kbd *kbd = handle->private;
+
+	reset_inactivity_timer(kbd);
+
+	if (type == EV_KEY && code == KEY_FN && appletb_tb_fn_toggle &&
+		(kbd->current_mode == APPLETB_KBD_MODE_SPCL ||
+		 kbd->current_mode == APPLETB_KBD_MODE_FN)) {
+		if (value == 1) {
+			kbd->saved_mode = kbd->current_mode;
+			appletb_kbd_set_mode(kbd, kbd->current_mode == APPLETB_KBD_MODE_SPCL
+						? APPLETB_KBD_MODE_FN : APPLETB_KBD_MODE_SPCL);
+		} else if (value == 0) {
+			if (kbd->saved_mode != kbd->current_mode)
+				appletb_kbd_set_mode(kbd, kbd->saved_mode);
+		}
+	}
+}
+
+static int appletb_kbd_inp_connect(struct input_handler *handler,
+			       struct input_dev *dev,
+			       const struct input_device_id *id)
+{
+	struct appletb_kbd *kbd = handler->private;
+	struct input_handle *handle;
+	int rc;
+
+	if (id->driver_info == APPLETB_DEVID_KEYBOARD) {
+		handle = &kbd->kbd_handle;
+		handle->name = "tbkbd";
+	} else if (id->driver_info == APPLETB_DEVID_TRACKPAD) {
+		handle = &kbd->tpd_handle;
+		handle->name = "tbtpd";
+	} else {
+		return -ENOENT;
+	}
+
+	if (handle->dev)
+		return -EEXIST;
+
+	handle->open = 0;
+	handle->dev = input_get_device(dev);
+	handle->handler = handler;
+	handle->private = kbd;
+
+	rc = input_register_handle(handle);
+	if (rc)
+		goto err_free_dev;
+
+	rc = input_open_device(handle);
+	if (rc)
+		goto err_unregister_handle;
+
+	return 0;
+
+ err_unregister_handle:
+	input_unregister_handle(handle);
+ err_free_dev:
+	input_put_device(handle->dev);
+	handle->dev = NULL;
+	return rc;
+}
+
+static void appletb_kbd_inp_disconnect(struct input_handle *handle)
+{
+	input_close_device(handle);
+	input_unregister_handle(handle);
+
+	input_put_device(handle->dev);
+	handle->dev = NULL;
+}
+
+static int appletb_kbd_input_configured(struct hid_device *hdev, struct hid_input *hidinput)
+{
+	int idx;
+	struct input_dev *input = hidinput->input;
+
+	/*
+	 * Clear various input capabilities that are blindly set by the hid
+	 * driver (usbkbd.c)
+	 */
+	memset(input->evbit, 0, sizeof(input->evbit));
+	memset(input->keybit, 0, sizeof(input->keybit));
+	memset(input->ledbit, 0, sizeof(input->ledbit));
+
+	__set_bit(EV_REP, input->evbit);
+
+	sparse_keymap_setup(input, appletb_kbd_keymap, NULL);
+
+	for (idx = 0; appletb_kbd_keymap[idx].type != KE_END; idx++)
+		input_set_capability(input, EV_KEY, appletb_kbd_keymap[idx].code);
+
+	return 0;
+}
+
+static const struct input_device_id appletb_kbd_input_devices[] = {
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_BUS |
+			INPUT_DEVICE_ID_MATCH_VENDOR |
+			INPUT_DEVICE_ID_MATCH_KEYBIT,
+		.bustype = BUS_USB,
+		.vendor = USB_VENDOR_ID_APPLE,
+		.keybit = { [BIT_WORD(KEY_FN)] = BIT_MASK(KEY_FN) },
+		.driver_info = APPLETB_DEVID_KEYBOARD,
+	},
+	{
+		.flags = INPUT_DEVICE_ID_MATCH_BUS |
+			INPUT_DEVICE_ID_MATCH_VENDOR |
+			INPUT_DEVICE_ID_MATCH_KEYBIT,
+		.bustype = BUS_USB,
+		.vendor = USB_VENDOR_ID_APPLE,
+		.keybit = { [BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH) },
+		.driver_info = APPLETB_DEVID_TRACKPAD,
+	},
+	{ }
+};
+
+static bool appletb_kbd_match_internal_device(struct input_handler *handler,
+					  struct input_dev *inp_dev)
+{
+	struct device *dev = &inp_dev->dev;
+
+	/* in kernel: dev && !is_usb_device(dev) */
+	while (dev && !(dev->type && dev->type->name &&
+			!strcmp(dev->type->name, "usb_device")))
+		dev = dev->parent;
+
+	/*
+	 * Apple labels all their internal keyboards and trackpads as such,
+	 * instead of maintaining an ever expanding list of product-id's we
+	 * just look at the device's product name.
+	 */
+	if (dev)
+		return !!strstr(to_usb_device(dev)->product, "Internal Keyboard");
+
+	return false;
+}
+
+static int appletb_kbd_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct appletb_kbd *kbd;
+	struct device *dev = &hdev->dev;
+	struct hid_field *mode_field;
+	int ret;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return dev_err_probe(dev, ret, "HID parse failed\n");
+
+	mode_field = hid_find_field(hdev, HID_OUTPUT_REPORT,
+				    HID_GD_KEYBOARD, HID_USAGE_MODE);
+	if (!mode_field)
+		return -ENODEV;
+
+	kbd = devm_kzalloc(dev, sizeof(*kbd), GFP_KERNEL);
+	if (!kbd)
+		return -ENOMEM;
+
+	kbd->mode_field = mode_field;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDINPUT);
+	if (ret)
+		return dev_err_probe(dev, ret, "HID hw start failed\n");
+
+	ret = hid_hw_open(hdev);
+	if (ret) {
+		dev_err_probe(dev, ret, "HID hw open failed\n");
+		goto stop_hw;
+	}
+
+	kbd->backlight_dev = backlight_device_get_by_name("appletb_backlight");
+	if (!kbd->backlight_dev) {
+		dev_err_probe(dev, -ENODEV, "Failed to get backlight device\n");
+	} else {
+		backlight_device_set_brightness(kbd->backlight_dev, 2);
+		INIT_DELAYED_WORK(&kbd->inactivity_work, appletb_inactivity_work);
+		INIT_WORK(&kbd->restore_brightness_work,
+			  appletb_restore_brightness_work);
+		mod_delayed_work(system_dfl_wq, &kbd->inactivity_work,
+				 secs_to_jiffies(appletb_tb_dim_timeout));
+	}
+
+	kbd->inp_handler.event = appletb_kbd_inp_event;
+	kbd->inp_handler.connect = appletb_kbd_inp_connect;
+	kbd->inp_handler.disconnect = appletb_kbd_inp_disconnect;
+	kbd->inp_handler.name = "appletb";
+	kbd->inp_handler.id_table = appletb_kbd_input_devices;
+	kbd->inp_handler.match = appletb_kbd_match_internal_device;
+	kbd->inp_handler.private = kbd;
+
+	ret = input_register_handler(&kbd->inp_handler);
+	if (ret) {
+		dev_err_probe(dev, ret, "Unable to register keyboard handler\n");
+		goto close_hw;
+	}
+
+	ret = appletb_kbd_set_mode(kbd, appletb_tb_def_mode);
+	if (ret) {
+		dev_err_probe(dev, ret, "Failed to set touchbar mode\n");
+		goto unregister_handler;
+	}
+
+	hid_set_drvdata(hdev, kbd);
+
+	return 0;
+
+unregister_handler:
+	input_unregister_handler(&kbd->inp_handler);
+close_hw:
+	hid_hw_close(hdev);
+stop_hw:
+	hid_hw_stop(hdev);
+	if (kbd->backlight_dev) {
+		cancel_delayed_work_sync(&kbd->inactivity_work);
+		cancel_work_sync(&kbd->restore_brightness_work);
+		put_device(&kbd->backlight_dev->dev);
+	}
+	return ret;
+}
+
+static void appletb_kbd_remove(struct hid_device *hdev)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+
+	appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
+
+	input_unregister_handler(&kbd->inp_handler);
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+
+	if (kbd->backlight_dev) {
+		cancel_delayed_work_sync(&kbd->inactivity_work);
+		cancel_work_sync(&kbd->restore_brightness_work);
+		put_device(&kbd->backlight_dev->dev);
+	}
+}
+
+static int appletb_kbd_suspend(struct hid_device *hdev, pm_message_t msg)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+
+	kbd->saved_mode = kbd->current_mode;
+	appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
+
+	return 0;
+}
+
+static int appletb_kbd_resume(struct hid_device *hdev)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+
+	appletb_kbd_set_mode(kbd, kbd->saved_mode);
+
+	return 0;
+}
+
+static const struct hid_device_id appletb_kbd_hid_ids[] = {
+	/* MacBook Pro's 2018, 2019, with T2 chip: iBridge Display */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, appletb_kbd_hid_ids);
+
+static struct hid_driver appletb_kbd_hid_driver = {
+	.name = "hid-appletb-kbd",
+	.id_table = appletb_kbd_hid_ids,
+	.probe = appletb_kbd_probe,
+	.remove = appletb_kbd_remove,
+	.event = appletb_kbd_hid_event,
+	.input_configured = appletb_kbd_input_configured,
+	.suspend = pm_ptr(appletb_kbd_suspend),
+	.resume = pm_ptr(appletb_kbd_resume),
+	.reset_resume = pm_ptr(appletb_kbd_resume),
+	.driver.dev_groups = appletb_kbd_groups,
+};
+module_hid_driver(appletb_kbd_hid_driver);
+
+/* The backlight driver should be loaded before the keyboard driver is initialised */
+MODULE_SOFTDEP("pre: hid_appletb_bl");
+
+MODULE_AUTHOR("Ronald Tschalär");
+MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>");
+MODULE_AUTHOR("Aditya Garg <gargaditya08@live.com>");
+MODULE_DESCRIPTION("MacBook Pro Touch Bar Keyboard Mode driver");
+MODULE_LICENSE("GPL");