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, 275 insertions, 0 deletions

diff --git a/drivers/leds/leds-max77705.c b/drivers/leds/leds-max77705.c
new file mode 100644
index 000000000..1e2054c1b
--- /dev/null
+++ b/drivers/leds/leds-max77705.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Based on leds-max77650 driver
+ *
+ * LED driver for MAXIM 77705 PMIC.
+ * Copyright (C) 2025 Dzmitry Sankouski <dsankouski@gmail.org>
+ */
+
+#include <linux/i2c.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/leds.h>
+#include <linux/mfd/max77705-private.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define MAX77705_LED_NUM_LEDS			4
+#define MAX77705_LED_EN_MASK			GENMASK(1, 0)
+#define MAX77705_LED_MAX_BRIGHTNESS		0xff
+#define MAX77705_LED_EN_SHIFT(reg)		(reg * MAX77705_RGBLED_EN_WIDTH)
+#define MAX77705_LED_REG_BRIGHTNESS(reg)	(reg + MAX77705_RGBLED_REG_LED0BRT)
+
+struct max77705_led {
+	struct led_classdev cdev;
+	struct led_classdev_mc mcdev;
+	struct regmap *regmap;
+
+	struct mc_subled *subled_info;
+};
+
+static const struct regmap_config max77705_leds_regmap_config = {
+	.reg_base = MAX77705_RGBLED_REG_BASE,
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX77705_LED_REG_END,
+};
+
+static int max77705_rgb_blink(struct led_classdev *cdev,
+				unsigned long *delay_on,
+				unsigned long *delay_off)
+{
+	struct max77705_led *led = container_of(cdev, struct max77705_led, cdev);
+	int value, on_value, off_value;
+
+	if (*delay_on < MAX77705_RGB_DELAY_100_STEP)
+		on_value = 0;
+	else if (*delay_on < MAX77705_RGB_DELAY_100_STEP_LIM)
+		on_value = *delay_on / MAX77705_RGB_DELAY_100_STEP - 1;
+	else if (*delay_on < MAX77705_RGB_DELAY_250_STEP_LIM)
+		on_value = (*delay_on - MAX77705_RGB_DELAY_100_STEP_LIM) /
+				MAX77705_RGB_DELAY_250_STEP +
+				MAX77705_RGB_DELAY_100_STEP_COUNT;
+	else
+		on_value = 15;
+
+	on_value <<= 4;
+
+	if (*delay_off < 1)
+		off_value = 0;
+	else if (*delay_off < MAX77705_RGB_DELAY_500_STEP)
+		off_value = 1;
+	else if (*delay_off < MAX77705_RGB_DELAY_500_STEP_LIM)
+		off_value = *delay_off / MAX77705_RGB_DELAY_500_STEP;
+	else if (*delay_off < MAX77705_RGB_DELAY_1000_STEP_LIM)
+		off_value = (*delay_off - MAX77705_RGB_DELAY_1000_STEP_LIM) /
+				MAX77705_RGB_DELAY_1000_STEP +
+				MAX77705_RGB_DELAY_500_STEP_COUNT;
+	else if (*delay_off < MAX77705_RGB_DELAY_2000_STEP_LIM)
+		off_value = (*delay_off - MAX77705_RGB_DELAY_2000_STEP_LIM) /
+				MAX77705_RGB_DELAY_2000_STEP +
+				MAX77705_RGB_DELAY_1000_STEP_COUNT;
+	else
+		off_value = 15;
+
+	value = on_value | off_value;
+	return regmap_write(led->regmap, MAX77705_RGBLED_REG_LEDBLNK, value);
+}
+
+static int max77705_led_brightness_set(struct regmap *regmap, struct mc_subled *subled,
+				int num_colors)
+{
+	int ret;
+
+	for (int i = 0; i < num_colors; i++) {
+		unsigned int channel, brightness;
+
+		channel = subled[i].channel;
+		brightness = subled[i].brightness;
+
+		if (brightness == LED_OFF) {
+			/* Flash OFF */
+			ret = regmap_update_bits(regmap,
+					MAX77705_RGBLED_REG_LEDEN,
+					MAX77705_LED_EN_MASK << MAX77705_LED_EN_SHIFT(channel), 0);
+		} else {
+			/* Set current */
+			ret = regmap_write(regmap, MAX77705_LED_REG_BRIGHTNESS(channel),
+					brightness);
+			if (ret < 0)
+				return ret;
+
+			ret = regmap_update_bits(regmap,
+					MAX77705_RGBLED_REG_LEDEN,
+					LED_ON << MAX77705_LED_EN_SHIFT(channel),
+					MAX77705_LED_EN_MASK << MAX77705_LED_EN_SHIFT(channel));
+		}
+	}
+
+	return ret;
+}
+
+static int max77705_led_brightness_set_single(struct led_classdev *cdev,
+					enum led_brightness brightness)
+{
+	struct max77705_led *led = container_of(cdev, struct max77705_led, cdev);
+
+	led->subled_info->brightness = brightness;
+
+	return max77705_led_brightness_set(led->regmap, led->subled_info, 1);
+}
+
+static int max77705_led_brightness_set_multi(struct led_classdev *cdev,
+					enum led_brightness brightness)
+{
+	struct led_classdev_mc *mcdev = lcdev_to_mccdev(cdev);
+	struct max77705_led *led = container_of(mcdev, struct max77705_led, mcdev);
+
+	led_mc_calc_color_components(mcdev, brightness);
+
+	return max77705_led_brightness_set(led->regmap, led->mcdev.subled_info, mcdev->num_colors);
+}
+
+static int max77705_parse_subled(struct device *dev, struct fwnode_handle *np,
+				struct mc_subled *info)
+{
+	u32 color = LED_COLOR_ID_GREEN;
+	u32 reg;
+	int ret;
+
+	ret = fwnode_property_read_u32(np, "reg", &reg);
+	if (ret || !reg || reg >= MAX77705_LED_NUM_LEDS)
+		return dev_err_probe(dev, -EINVAL, "invalid \"reg\" of %pOFn\n", np);
+
+	info->channel = reg;
+
+	ret = fwnode_property_read_u32(np, "color", &color);
+	if (ret < 0 && ret != -EINVAL)
+		return dev_err_probe(dev, ret,
+				     "failed to parse \"color\" of %pOF\n", np);
+
+	info->color_index = color;
+
+	return 0;
+}
+
+static int max77705_add_led(struct device *dev, struct regmap *regmap, struct fwnode_handle *np)
+{
+	int ret, i = 0;
+	unsigned int color, reg;
+	struct max77705_led *led;
+	struct led_classdev *cdev;
+	struct mc_subled *info;
+	struct fwnode_handle *child;
+	struct led_init_data init_data = {};
+
+	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
+	if (!led)
+		return -ENOMEM;
+
+	ret = fwnode_property_read_u32(np, "color", &color);
+	if (ret < 0 && ret != -EINVAL)
+		return dev_err_probe(dev, ret,
+			      "failed to parse \"color\" of %pOF\n", np);
+
+	led->regmap = regmap;
+	init_data.fwnode = np;
+
+	if (color == LED_COLOR_ID_RGB) {
+		int num_channels = of_get_available_child_count(to_of_node(np));
+
+		ret = fwnode_property_read_u32(np, "reg", &reg);
+		if (ret || reg >= MAX77705_LED_NUM_LEDS)
+			return -EINVAL;
+
+		info = devm_kcalloc(dev, num_channels, sizeof(*info), GFP_KERNEL);
+		if (!info)
+			return -ENOMEM;
+
+		cdev = &led->mcdev.led_cdev;
+		cdev->max_brightness = MAX77705_LED_MAX_BRIGHTNESS;
+		cdev->brightness_set_blocking = max77705_led_brightness_set_multi;
+		cdev->blink_set = max77705_rgb_blink;
+
+		fwnode_for_each_child_node(np, child) {
+			ret = max77705_parse_subled(dev, child, &info[i]);
+			if (ret < 0)
+				return ret;
+
+			info[i].intensity = 0;
+			i++;
+		}
+
+		led->mcdev.subled_info = info;
+		led->mcdev.num_colors = num_channels;
+		led->cdev = *cdev;
+
+		ret = devm_led_classdev_multicolor_register_ext(dev, &led->mcdev, &init_data);
+		if (ret)
+			return ret;
+
+		ret = max77705_led_brightness_set_multi(&led->cdev, LED_OFF);
+		if (ret)
+			return ret;
+	} else {
+		info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+		if (!info)
+			return -ENOMEM;
+
+		max77705_parse_subled(dev, np, info);
+
+		led->subled_info = info;
+		led->cdev.brightness_set_blocking = max77705_led_brightness_set_single;
+		led->cdev.blink_set = max77705_rgb_blink;
+		led->cdev.max_brightness = MAX77705_LED_MAX_BRIGHTNESS;
+
+		ret = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
+		if (ret)
+			return ret;
+
+		ret = max77705_led_brightness_set_single(&led->cdev, LED_OFF);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int max77705_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct i2c_client *i2c = to_i2c_client(pdev->dev.parent);
+	struct regmap *regmap;
+	int ret;
+
+	regmap = devm_regmap_init_i2c(i2c, &max77705_leds_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to register LEDs regmap\n");
+
+	device_for_each_child_node_scoped(dev, child) {
+		ret = max77705_add_led(dev, regmap, child);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id max77705_led_of_match[] = {
+	{ .compatible = "maxim,max77705-rgb" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max77705_led_of_match);
+
+static struct platform_driver max77705_led_driver = {
+	.driver = {
+		.name = "max77705-led",
+		.of_match_table = max77705_led_of_match,
+	},
+	.probe = max77705_led_probe,
+};
+module_platform_driver(max77705_led_driver);
+
+MODULE_DESCRIPTION("Maxim MAX77705 LED driver");
+MODULE_AUTHOR("Dzmitry Sankouski <dsankouski@gmail.com>");
+MODULE_LICENSE("GPL");