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, 197 insertions, 0 deletions

diff --git a/drivers/input/misc/pf1550-onkey.c b/drivers/input/misc/pf1550-onkey.c
new file mode 100644
index 000000000..0d1b570bb
--- /dev/null
+++ b/drivers/input/misc/pf1550-onkey.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the PF1550 ONKEY
+ * Copyright (C) 2016 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * Portions Copyright (c) 2025 Savoir-faire Linux Inc.
+ * Samuel Kayode <samuel.kayode@savoirfairelinux.com>
+ */
+
+#include <linux/err.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/pf1550.h>
+#include <linux/platform_device.h>
+
+#define PF1550_ONKEY_IRQ_NR	6
+
+struct onkey_drv_data {
+	struct device *dev;
+	const struct pf1550_ddata *pf1550;
+	bool wakeup;
+	struct input_dev *input;
+};
+
+static irqreturn_t pf1550_onkey_irq_handler(int irq, void *data)
+{
+	struct onkey_drv_data *onkey = data;
+	struct platform_device *pdev = to_platform_device(onkey->dev);
+	int i, state, irq_type = -1;
+
+	for (i = 0; i < PF1550_ONKEY_IRQ_NR; i++)
+		if (irq == platform_get_irq(pdev, i))
+			irq_type = i;
+
+	switch (irq_type) {
+	case PF1550_ONKEY_IRQ_PUSHI:
+		state = 0;
+		break;
+	case PF1550_ONKEY_IRQ_1SI:
+	case PF1550_ONKEY_IRQ_2SI:
+	case PF1550_ONKEY_IRQ_3SI:
+	case PF1550_ONKEY_IRQ_4SI:
+	case PF1550_ONKEY_IRQ_8SI:
+		state = 1;
+		break;
+	default:
+		dev_err(onkey->dev, "onkey interrupt: irq %d occurred\n",
+			irq_type);
+		return IRQ_HANDLED;
+	}
+
+	input_event(onkey->input, EV_KEY, KEY_POWER, state);
+	input_sync(onkey->input);
+
+	return IRQ_HANDLED;
+}
+
+static int pf1550_onkey_probe(struct platform_device *pdev)
+{
+	struct onkey_drv_data *onkey;
+	struct input_dev *input;
+	bool key_power = false;
+	int i, irq, error;
+
+	onkey = devm_kzalloc(&pdev->dev, sizeof(*onkey), GFP_KERNEL);
+	if (!onkey)
+		return -ENOMEM;
+
+	onkey->dev = &pdev->dev;
+
+	onkey->pf1550 = dev_get_drvdata(pdev->dev.parent);
+	if (!onkey->pf1550->regmap)
+		return dev_err_probe(&pdev->dev, -ENODEV,
+				     "failed to get regmap\n");
+
+	onkey->wakeup = device_property_read_bool(pdev->dev.parent,
+						  "wakeup-source");
+
+	if (device_property_read_bool(pdev->dev.parent,
+				      "nxp,disable-key-power")) {
+		error = regmap_clear_bits(onkey->pf1550->regmap,
+					  PF1550_PMIC_REG_PWRCTRL1,
+					  PF1550_ONKEY_RST_EN);
+		if (error)
+			return dev_err_probe(&pdev->dev, error,
+					     "failed: disable turn system off");
+	} else {
+		key_power = true;
+	}
+
+	input = devm_input_allocate_device(&pdev->dev);
+	if (!input)
+		return dev_err_probe(&pdev->dev, -ENOMEM,
+				     "failed to allocate the input device\n");
+
+	input->name = pdev->name;
+	input->phys = "pf1550-onkey/input0";
+	input->id.bustype = BUS_HOST;
+
+	if (key_power)
+		input_set_capability(input, EV_KEY, KEY_POWER);
+
+	onkey->input = input;
+	platform_set_drvdata(pdev, onkey);
+
+	for (i = 0; i < PF1550_ONKEY_IRQ_NR; i++) {
+		irq = platform_get_irq(pdev, i);
+		if (irq < 0)
+			return irq;
+
+		error = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+						  pf1550_onkey_irq_handler,
+						  IRQF_NO_SUSPEND,
+						  "pf1550-onkey", onkey);
+		if (error)
+			return dev_err_probe(&pdev->dev, error,
+					     "failed: irq request (IRQ: %d)\n",
+					     i);
+	}
+
+	error = input_register_device(input);
+	if (error)
+		return dev_err_probe(&pdev->dev, error,
+				     "failed to register input device\n");
+
+	device_init_wakeup(&pdev->dev, onkey->wakeup);
+
+	return 0;
+}
+
+static int pf1550_onkey_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct onkey_drv_data *onkey = platform_get_drvdata(pdev);
+	int i, irq;
+
+	if (!device_may_wakeup(&pdev->dev))
+		regmap_write(onkey->pf1550->regmap,
+			     PF1550_PMIC_REG_ONKEY_INT_MASK0,
+			     ONKEY_IRQ_PUSHI | ONKEY_IRQ_1SI | ONKEY_IRQ_2SI |
+			     ONKEY_IRQ_3SI | ONKEY_IRQ_4SI | ONKEY_IRQ_8SI);
+	else
+		for (i = 0; i < PF1550_ONKEY_IRQ_NR; i++) {
+			irq = platform_get_irq(pdev, i);
+			if (irq > 0)
+				enable_irq_wake(irq);
+		}
+
+	return 0;
+}
+
+static int pf1550_onkey_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct onkey_drv_data *onkey = platform_get_drvdata(pdev);
+	int i, irq;
+
+	if (!device_may_wakeup(&pdev->dev))
+		regmap_write(onkey->pf1550->regmap,
+			     PF1550_PMIC_REG_ONKEY_INT_MASK0,
+			     ~((u8)(ONKEY_IRQ_PUSHI | ONKEY_IRQ_1SI |
+			     ONKEY_IRQ_2SI | ONKEY_IRQ_3SI | ONKEY_IRQ_4SI |
+			     ONKEY_IRQ_8SI)));
+	else
+		for (i = 0; i < PF1550_ONKEY_IRQ_NR; i++) {
+			irq = platform_get_irq(pdev, i);
+			if (irq > 0)
+				disable_irq_wake(irq);
+		}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(pf1550_onkey_pm_ops, pf1550_onkey_suspend,
+			 pf1550_onkey_resume);
+
+static const struct platform_device_id pf1550_onkey_id[] = {
+	{ "pf1550-onkey", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, pf1550_onkey_id);
+
+static struct platform_driver pf1550_onkey_driver = {
+	.driver = {
+		.name = "pf1550-onkey",
+		.pm   = pm_sleep_ptr(&pf1550_onkey_pm_ops),
+	},
+	.probe = pf1550_onkey_probe,
+	.id_table = pf1550_onkey_id,
+};
+module_platform_driver(pf1550_onkey_driver);
+
+MODULE_AUTHOR("Freescale Semiconductor");
+MODULE_DESCRIPTION("PF1550 onkey Driver");
+MODULE_LICENSE("GPL");