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, 150 insertions, 0 deletions

diff --git a/drivers/input/misc/tps65219-pwrbutton.c b/drivers/input/misc/tps65219-pwrbutton.c
new file mode 100644
index 000000000..7a58bae4f
--- /dev/null
+++ b/drivers/input/misc/tps65219-pwrbutton.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Driver for TPS65219 Push Button
+//
+// Copyright (C) 2022 BayLibre Incorporated - https://www.baylibre.com/
+
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/tps65219.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+struct tps65219_pwrbutton {
+	struct device *dev;
+	struct input_dev *idev;
+	char phys[32];
+};
+
+static irqreturn_t tps65219_pb_push_irq(int irq, void *_pwr)
+{
+	struct tps65219_pwrbutton *pwr = _pwr;
+
+	input_report_key(pwr->idev, KEY_POWER, 1);
+	pm_wakeup_event(pwr->dev, 0);
+	input_sync(pwr->idev);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t tps65219_pb_release_irq(int irq, void *_pwr)
+{
+	struct tps65219_pwrbutton *pwr = _pwr;
+
+	input_report_key(pwr->idev, KEY_POWER, 0);
+	input_sync(pwr->idev);
+
+	return IRQ_HANDLED;
+}
+
+static int tps65219_pb_probe(struct platform_device *pdev)
+{
+	struct tps65219 *tps = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct tps65219_pwrbutton *pwr;
+	struct input_dev *idev;
+	int error;
+	int push_irq;
+	int release_irq;
+
+	pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
+	if (!pwr)
+		return -ENOMEM;
+
+	idev = devm_input_allocate_device(dev);
+	if (!idev)
+		return -ENOMEM;
+
+	idev->name = pdev->name;
+	snprintf(pwr->phys, sizeof(pwr->phys), "%s/input0",
+		 pdev->name);
+	idev->phys = pwr->phys;
+	idev->id.bustype = BUS_I2C;
+
+	input_set_capability(idev, EV_KEY, KEY_POWER);
+
+	pwr->dev = dev;
+	pwr->idev = idev;
+	device_init_wakeup(dev, true);
+
+	push_irq = platform_get_irq(pdev, 0);
+	if (push_irq < 0)
+		return -EINVAL;
+
+	release_irq = platform_get_irq(pdev, 1);
+	if (release_irq < 0)
+		return -EINVAL;
+
+	error = devm_request_threaded_irq(dev, push_irq, NULL,
+					  tps65219_pb_push_irq,
+					  IRQF_ONESHOT,
+					  dev->init_name, pwr);
+	if (error) {
+		dev_err(dev, "failed to request push IRQ #%d: %d\n", push_irq,
+			error);
+		return error;
+	}
+
+	error = devm_request_threaded_irq(dev, release_irq, NULL,
+					  tps65219_pb_release_irq,
+					  IRQF_ONESHOT,
+					  dev->init_name, pwr);
+	if (error) {
+		dev_err(dev, "failed to request release IRQ #%d: %d\n",
+			release_irq, error);
+		return error;
+	}
+
+	error = input_register_device(idev);
+	if (error) {
+		dev_err(dev, "Can't register power button: %d\n", error);
+		return error;
+	}
+
+	/* Enable interrupts for the pushbutton */
+	regmap_clear_bits(tps->regmap, TPS65219_REG_MASK_CONFIG,
+			  TPS65219_REG_MASK_INT_FOR_PB_MASK);
+
+	/* Set PB/EN/VSENSE pin to be a pushbutton */
+	regmap_update_bits(tps->regmap, TPS65219_REG_MFP_2_CONFIG,
+			   TPS65219_MFP_2_EN_PB_VSENSE_MASK, TPS65219_MFP_2_PB);
+
+	return 0;
+}
+
+static void tps65219_pb_remove(struct platform_device *pdev)
+{
+	struct tps65219 *tps = dev_get_drvdata(pdev->dev.parent);
+	int ret;
+
+	/* Disable interrupt for the pushbutton */
+	ret = regmap_set_bits(tps->regmap, TPS65219_REG_MASK_CONFIG,
+			      TPS65219_REG_MASK_INT_FOR_PB_MASK);
+	if (ret)
+		dev_warn(&pdev->dev, "Failed to disable irq (%pe)\n", ERR_PTR(ret));
+}
+
+static const struct platform_device_id tps65219_pwrbtn_id_table[] = {
+	{ "tps65219-pwrbutton", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, tps65219_pwrbtn_id_table);
+
+static struct platform_driver tps65219_pb_driver = {
+	.probe = tps65219_pb_probe,
+	.remove = tps65219_pb_remove,
+	.driver = {
+		.name = "tps65219_pwrbutton",
+	},
+	.id_table = tps65219_pwrbtn_id_table,
+};
+module_platform_driver(tps65219_pb_driver);
+
+MODULE_DESCRIPTION("TPS65219 Power Button");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Markus Schneider-Pargmann <msp@baylibre.com");