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, 163 insertions, 0 deletions

diff --git a/drivers/input/misc/twl4030-pwrbutton.c b/drivers/input/misc/twl4030-pwrbutton.c
new file mode 100644
index 000000000..3e94a5995
--- /dev/null
+++ b/drivers/input/misc/twl4030-pwrbutton.c
@@ -0,0 +1,163 @@
+/*
+ * TWL4030 Power Button Input Driver
+ *
+ * Copyright (C) 2008-2009 Nokia Corporation
+ *
+ * Written by Peter De Schrijver <peter.de-schrijver@nokia.com>
+ * Several fixes by Felipe Balbi <felipe.balbi@nokia.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/bits.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/twl.h>
+
+#define PWR_PWRON_IRQ BIT(0)
+
+struct twl_pwrbutton_chipdata {
+	u8 status_reg;
+	bool need_manual_irq;
+};
+
+static const struct twl_pwrbutton_chipdata twl4030_chipdata = {
+	.status_reg = 0xf,
+	.need_manual_irq = false,
+};
+
+static const struct twl_pwrbutton_chipdata twl6030_chipdata = {
+	.status_reg = 0x2,
+	.need_manual_irq = true,
+};
+
+static irqreturn_t powerbutton_irq(int irq, void *_pwr)
+{
+	struct input_dev *pwr = _pwr;
+	const struct twl_pwrbutton_chipdata *pdata = dev_get_drvdata(pwr->dev.parent);
+	int err;
+	u8 value;
+
+	err = twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &value, pdata->status_reg);
+	if (!err)  {
+		pm_wakeup_event(pwr->dev.parent, 0);
+		input_report_key(pwr, KEY_POWER, value & PWR_PWRON_IRQ);
+		input_sync(pwr);
+	} else {
+		dev_err(pwr->dev.parent, "twl4030: i2c error %d while reading"
+			" TWL4030 PM_MASTER STS_HW_CONDITIONS register\n", err);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int twl4030_pwrbutton_probe(struct platform_device *pdev)
+{
+	const struct twl_pwrbutton_chipdata *pdata;
+	struct input_dev *pwr;
+	int irq = platform_get_irq(pdev, 0);
+	int err;
+
+	pdata = device_get_match_data(&pdev->dev);
+	if (!pdata)
+		return -EINVAL;
+
+	platform_set_drvdata(pdev, (void *)pdata);
+
+	pwr = devm_input_allocate_device(&pdev->dev);
+	if (!pwr) {
+		dev_err(&pdev->dev, "Can't allocate power button\n");
+		return -ENOMEM;
+	}
+
+	input_set_capability(pwr, EV_KEY, KEY_POWER);
+	pwr->name = "twl4030_pwrbutton";
+	pwr->phys = "twl4030_pwrbutton/input0";
+	pwr->dev.parent = &pdev->dev;
+
+	err = devm_request_threaded_irq(&pdev->dev, irq, NULL, powerbutton_irq,
+			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
+			IRQF_ONESHOT,
+			"twl4030_pwrbutton", pwr);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Can't get IRQ for pwrbutton: %d\n", err);
+		return err;
+	}
+
+	err = input_register_device(pwr);
+	if (err) {
+		dev_err(&pdev->dev, "Can't register power button: %d\n", err);
+		return err;
+	}
+
+	if (pdata->need_manual_irq) {
+		err = twl6030_interrupt_unmask(0x01, REG_INT_MSK_LINE_A);
+		if (err)
+			return err;
+
+		err = twl6030_interrupt_unmask(0x01, REG_INT_MSK_STS_A);
+		if (err)
+			return err;
+	}
+
+	device_init_wakeup(&pdev->dev, true);
+
+	return 0;
+}
+
+static void twl4030_pwrbutton_remove(struct platform_device *pdev)
+{
+	const struct twl_pwrbutton_chipdata *pdata = platform_get_drvdata(pdev);
+
+	if (pdata->need_manual_irq) {
+		twl6030_interrupt_mask(0x01, REG_INT_MSK_LINE_A);
+		twl6030_interrupt_mask(0x01, REG_INT_MSK_STS_A);
+	}
+}
+
+static const struct of_device_id twl4030_pwrbutton_dt_match_table[] = {
+	{
+		.compatible = "ti,twl4030-pwrbutton",
+		.data = &twl4030_chipdata,
+	},
+	{
+		.compatible = "ti,twl6030-pwrbutton",
+		.data = &twl6030_chipdata,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, twl4030_pwrbutton_dt_match_table);
+
+static struct platform_driver twl4030_pwrbutton_driver = {
+	.probe		= twl4030_pwrbutton_probe,
+	.remove		= twl4030_pwrbutton_remove,
+	.driver		= {
+		.name	= "twl4030_pwrbutton",
+		.of_match_table = twl4030_pwrbutton_dt_match_table,
+	},
+};
+module_platform_driver(twl4030_pwrbutton_driver);
+
+MODULE_ALIAS("platform:twl4030_pwrbutton");
+MODULE_DESCRIPTION("Triton2 Power Button");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Peter De Schrijver <peter.de-schrijver@nokia.com>");
+MODULE_AUTHOR("Felipe Balbi <felipe.balbi@nokia.com>");
+