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, 160 insertions, 0 deletions

diff --git a/drivers/input/misc/tps65218-pwrbutton.c b/drivers/input/misc/tps65218-pwrbutton.c
new file mode 100644
index 000000000..fc450fce0
--- /dev/null
+++ b/drivers/input/misc/tps65218-pwrbutton.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Texas Instruments' TPS65217 and TPS65218 Power Button Input Driver
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Felipe Balbi <balbi@ti.com>
+ * Author: Marcin Niestroj <m.niestroj@grinn-global.com>
+ */
+
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/tps65217.h>
+#include <linux/mfd/tps65218.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+struct tps6521x_data {
+	unsigned int reg_status;
+	unsigned int pb_mask;
+	const char *name;
+};
+
+static const struct tps6521x_data tps65217_data = {
+	.reg_status = TPS65217_REG_STATUS,
+	.pb_mask = TPS65217_STATUS_PB,
+	.name = "tps65217_pwrbutton",
+};
+
+static const struct tps6521x_data tps65218_data = {
+	.reg_status = TPS65218_REG_STATUS,
+	.pb_mask = TPS65218_STATUS_PB_STATE,
+	.name = "tps65218_pwrbutton",
+};
+
+struct tps6521x_pwrbutton {
+	struct device *dev;
+	struct regmap *regmap;
+	struct input_dev *idev;
+	const struct tps6521x_data *data;
+	char phys[32];
+};
+
+static const struct of_device_id of_tps6521x_pb_match[] = {
+	{ .compatible = "ti,tps65217-pwrbutton", .data = &tps65217_data },
+	{ .compatible = "ti,tps65218-pwrbutton", .data = &tps65218_data },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, of_tps6521x_pb_match);
+
+static irqreturn_t tps6521x_pb_irq(int irq, void *_pwr)
+{
+	struct tps6521x_pwrbutton *pwr = _pwr;
+	const struct tps6521x_data *tps_data = pwr->data;
+	unsigned int reg;
+	int error;
+
+	error = regmap_read(pwr->regmap, tps_data->reg_status, &reg);
+	if (error) {
+		dev_err(pwr->dev, "can't read register: %d\n", error);
+		goto out;
+	}
+
+	if (reg & tps_data->pb_mask) {
+		input_report_key(pwr->idev, KEY_POWER, 1);
+		pm_wakeup_event(pwr->dev, 0);
+	} else {
+		input_report_key(pwr->idev, KEY_POWER, 0);
+	}
+
+	input_sync(pwr->idev);
+
+out:
+	return IRQ_HANDLED;
+}
+
+static int tps6521x_pb_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct tps6521x_pwrbutton *pwr;
+	struct input_dev *idev;
+	const struct of_device_id *match;
+	int error;
+	int irq;
+
+	match = of_match_node(of_tps6521x_pb_match, dev->of_node);
+	if (!match)
+		return -ENXIO;
+
+	pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
+	if (!pwr)
+		return -ENOMEM;
+
+	pwr->data = match->data;
+
+	idev = devm_input_allocate_device(dev);
+	if (!idev)
+		return -ENOMEM;
+
+	idev->name = pwr->data->name;
+	snprintf(pwr->phys, sizeof(pwr->phys), "%s/input0",
+		pwr->data->name);
+	idev->phys = pwr->phys;
+	idev->dev.parent = dev;
+	idev->id.bustype = BUS_I2C;
+
+	input_set_capability(idev, EV_KEY, KEY_POWER);
+
+	pwr->regmap = dev_get_regmap(dev->parent, NULL);
+	pwr->dev = dev;
+	pwr->idev = idev;
+	device_init_wakeup(dev, true);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -EINVAL;
+
+	error = devm_request_threaded_irq(dev, irq, NULL, tps6521x_pb_irq,
+					  IRQF_TRIGGER_RISING |
+						IRQF_TRIGGER_FALLING |
+						IRQF_ONESHOT,
+					  pwr->data->name, pwr);
+	if (error) {
+		dev_err(dev, "failed to request IRQ #%d: %d\n", irq, error);
+		return error;
+	}
+
+	error= input_register_device(idev);
+	if (error) {
+		dev_err(dev, "Can't register power button: %d\n", error);
+		return error;
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id tps6521x_pwrbtn_id_table[] = {
+	{ "tps65218-pwrbutton", },
+	{ "tps65217-pwrbutton", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, tps6521x_pwrbtn_id_table);
+
+static struct platform_driver tps6521x_pb_driver = {
+	.probe	= tps6521x_pb_probe,
+	.driver	= {
+		.name	= "tps6521x_pwrbutton",
+		.of_match_table = of_tps6521x_pb_match,
+	},
+	.id_table = tps6521x_pwrbtn_id_table,
+};
+module_platform_driver(tps6521x_pb_driver);
+
+MODULE_DESCRIPTION("TPS6521X Power Button");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");