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, 217 insertions, 0 deletions

diff --git a/drivers/extcon/extcon-intel-int3496.c b/drivers/extcon/extcon-intel-int3496.c
new file mode 100644
index 000000000..7d16d5b7d
--- /dev/null
+++ b/drivers/extcon/extcon-intel-int3496.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel INT3496 ACPI device extcon driver
+ *
+ * Copyright (c) 2016 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Based on android x86 kernel code which is:
+ *
+ * Copyright (c) 2014, Intel Corporation.
+ * Author: David Cohen <david.a.cohen@linux.intel.com>
+ */
+
+#include <linux/acpi.h>
+#include <linux/devm-helpers.h>
+#include <linux/extcon-provider.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define INT3496_GPIO_USB_ID	0
+#define INT3496_GPIO_VBUS_EN	1
+#define INT3496_GPIO_USB_MUX	2
+#define DEBOUNCE_TIME		msecs_to_jiffies(50)
+
+struct int3496_data {
+	struct device *dev;
+	struct extcon_dev *edev;
+	struct delayed_work work;
+	struct gpio_desc *gpio_usb_id;
+	struct gpio_desc *gpio_vbus_en;
+	struct gpio_desc *gpio_usb_mux;
+	struct regulator *vbus_boost;
+	int usb_id_irq;
+	bool vbus_boost_enabled;
+};
+
+static const unsigned int int3496_cable[] = {
+	EXTCON_USB_HOST,
+	EXTCON_NONE,
+};
+
+static const struct acpi_gpio_params id_gpios = { INT3496_GPIO_USB_ID, 0, false };
+static const struct acpi_gpio_params vbus_gpios = { INT3496_GPIO_VBUS_EN, 0, false };
+static const struct acpi_gpio_params mux_gpios = { INT3496_GPIO_USB_MUX, 0, false };
+
+static const struct acpi_gpio_mapping acpi_int3496_default_gpios[] = {
+	/*
+	 * Some platforms have a bug in ACPI GPIO description making IRQ
+	 * GPIO to be output only. Ask the GPIO core to ignore this limit.
+	 */
+	{ "id-gpios", &id_gpios, 1, ACPI_GPIO_QUIRK_NO_IO_RESTRICTION },
+	{ "vbus-gpios", &vbus_gpios, 1 },
+	{ "mux-gpios", &mux_gpios, 1 },
+	{ },
+};
+
+static void int3496_set_vbus_boost(struct int3496_data *data, bool enable)
+{
+	int ret;
+
+	if (IS_ERR_OR_NULL(data->vbus_boost))
+		return;
+
+	if (data->vbus_boost_enabled == enable)
+		return;
+
+	if (enable)
+		ret = regulator_enable(data->vbus_boost);
+	else
+		ret = regulator_disable(data->vbus_boost);
+
+	if (ret == 0)
+		data->vbus_boost_enabled = enable;
+	else
+		dev_err(data->dev, "Error updating Vbus boost regulator: %d\n", ret);
+}
+
+static void int3496_do_usb_id(struct work_struct *work)
+{
+	struct int3496_data *data =
+		container_of(work, struct int3496_data, work.work);
+	int id = gpiod_get_value_cansleep(data->gpio_usb_id);
+
+	/* id == 1: PERIPHERAL, id == 0: HOST */
+	dev_dbg(data->dev, "Connected %s cable\n", id ? "PERIPHERAL" : "HOST");
+
+	/*
+	 * Peripheral: set USB mux to peripheral and disable VBUS
+	 * Host: set USB mux to host and enable VBUS
+	 */
+	if (!IS_ERR(data->gpio_usb_mux))
+		gpiod_direction_output(data->gpio_usb_mux, id);
+
+	if (!IS_ERR(data->gpio_vbus_en))
+		gpiod_direction_output(data->gpio_vbus_en, !id);
+	else
+		int3496_set_vbus_boost(data, !id);
+
+	extcon_set_state_sync(data->edev, EXTCON_USB_HOST, !id);
+}
+
+static irqreturn_t int3496_thread_isr(int irq, void *priv)
+{
+	struct int3496_data *data = priv;
+
+	/* Let the pin settle before processing it */
+	mod_delayed_work(system_percpu_wq, &data->work, DEBOUNCE_TIME);
+
+	return IRQ_HANDLED;
+}
+
+static int int3496_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct int3496_data *data;
+	int ret;
+
+	if (has_acpi_companion(dev)) {
+		ret = devm_acpi_dev_add_driver_gpios(dev, acpi_int3496_default_gpios);
+		if (ret) {
+			dev_err(dev, "can't add GPIO ACPI mapping\n");
+			return ret;
+		}
+	}
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->dev = dev;
+	ret = devm_delayed_work_autocancel(dev, &data->work, int3496_do_usb_id);
+	if (ret)
+		return ret;
+
+	data->gpio_usb_id =
+		devm_gpiod_get(dev, "id", GPIOD_IN | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
+	if (IS_ERR(data->gpio_usb_id)) {
+		ret = PTR_ERR(data->gpio_usb_id);
+		dev_err(dev, "can't request USB ID GPIO: %d\n", ret);
+		return ret;
+	}
+
+	data->usb_id_irq = gpiod_to_irq(data->gpio_usb_id);
+	if (data->usb_id_irq < 0) {
+		dev_err(dev, "can't get USB ID IRQ: %d\n", data->usb_id_irq);
+		return data->usb_id_irq;
+	}
+
+	data->gpio_vbus_en = devm_gpiod_get(dev, "vbus", GPIOD_ASIS);
+	if (IS_ERR(data->gpio_vbus_en)) {
+		dev_dbg(dev, "can't request VBUS EN GPIO\n");
+		data->vbus_boost = devm_regulator_get_optional(dev, "vbus");
+	}
+
+	data->gpio_usb_mux = devm_gpiod_get(dev, "mux", GPIOD_ASIS);
+	if (IS_ERR(data->gpio_usb_mux))
+		dev_dbg(dev, "can't request USB MUX GPIO\n");
+
+	/* register extcon device */
+	data->edev = devm_extcon_dev_allocate(dev, int3496_cable);
+	if (IS_ERR(data->edev))
+		return -ENOMEM;
+
+	ret = devm_extcon_dev_register(dev, data->edev);
+	if (ret < 0) {
+		dev_err(dev, "can't register extcon device: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(dev, data->usb_id_irq,
+					NULL, int3496_thread_isr,
+					IRQF_SHARED | IRQF_ONESHOT |
+					IRQF_TRIGGER_RISING |
+					IRQF_TRIGGER_FALLING,
+					dev_name(dev), data);
+	if (ret < 0) {
+		dev_err(dev, "can't request IRQ for USB ID GPIO: %d\n", ret);
+		return ret;
+	}
+
+	/* process id-pin so that we start with the right status */
+	queue_delayed_work(system_percpu_wq, &data->work, 0);
+	flush_delayed_work(&data->work);
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+}
+
+static const struct acpi_device_id int3496_acpi_match[] = {
+	{ "INT3496" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, int3496_acpi_match);
+
+static const struct platform_device_id int3496_ids[] = {
+	{ .name = "intel-int3496" },
+	{},
+};
+MODULE_DEVICE_TABLE(platform, int3496_ids);
+
+static struct platform_driver int3496_driver = {
+	.driver = {
+		.name = "intel-int3496",
+		.acpi_match_table = int3496_acpi_match,
+	},
+	.probe = int3496_probe,
+	.id_table = int3496_ids,
+};
+
+module_platform_driver(int3496_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("Intel INT3496 ACPI device extcon driver");
+MODULE_LICENSE("GPL v2");