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, 185 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/dynapro.c b/drivers/input/touchscreen/dynapro.c
new file mode 100644
index 000000000..943ba8c2f
--- /dev/null
+++ b/drivers/input/touchscreen/dynapro.c
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Dynapro serial touchscreen driver
+ *
+ * Copyright (c) 2009 Tias Guns
+ * Based on the inexio driver (c) Vojtech Pavlik and Dan Streetman and
+ * Richard Lemon
+ */
+
+
+/*
+ * 2009/09/19 Tias Guns <tias@ulyssis.org>
+ *   Copied inexio.c and edited for Dynapro protocol (from retired Xorg module)
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+
+#define DRIVER_DESC	"Dynapro serial touchscreen driver"
+
+MODULE_AUTHOR("Tias Guns <tias@ulyssis.org>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/*
+ * Definitions & global arrays.
+ */
+
+#define DYNAPRO_FORMAT_TOUCH_BIT 0x40
+#define DYNAPRO_FORMAT_LENGTH 3
+#define DYNAPRO_RESPONSE_BEGIN_BYTE 0x80
+
+#define DYNAPRO_MIN_XC 0
+#define DYNAPRO_MAX_XC 0x3ff
+#define DYNAPRO_MIN_YC 0
+#define DYNAPRO_MAX_YC 0x3ff
+
+#define DYNAPRO_GET_XC(data) (data[1] | ((data[0] & 0x38) << 4))
+#define DYNAPRO_GET_YC(data) (data[2] | ((data[0] & 0x07) << 7))
+#define DYNAPRO_GET_TOUCHED(data) (DYNAPRO_FORMAT_TOUCH_BIT & data[0])
+
+/*
+ * Per-touchscreen data.
+ */
+
+struct dynapro {
+	struct input_dev *dev;
+	struct serio *serio;
+	int idx;
+	unsigned char data[DYNAPRO_FORMAT_LENGTH];
+	char phys[32];
+};
+
+static void dynapro_process_data(struct dynapro *pdynapro)
+{
+	struct input_dev *dev = pdynapro->dev;
+
+	if (DYNAPRO_FORMAT_LENGTH == ++pdynapro->idx) {
+		input_report_abs(dev, ABS_X, DYNAPRO_GET_XC(pdynapro->data));
+		input_report_abs(dev, ABS_Y, DYNAPRO_GET_YC(pdynapro->data));
+		input_report_key(dev, BTN_TOUCH,
+				 DYNAPRO_GET_TOUCHED(pdynapro->data));
+		input_sync(dev);
+
+		pdynapro->idx = 0;
+	}
+}
+
+static irqreturn_t dynapro_interrupt(struct serio *serio,
+		unsigned char data, unsigned int flags)
+{
+	struct dynapro *pdynapro = serio_get_drvdata(serio);
+
+	pdynapro->data[pdynapro->idx] = data;
+
+	if (DYNAPRO_RESPONSE_BEGIN_BYTE & pdynapro->data[0])
+		dynapro_process_data(pdynapro);
+	else
+		dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
+			pdynapro->data[0]);
+
+	return IRQ_HANDLED;
+}
+
+static void dynapro_disconnect(struct serio *serio)
+{
+	struct dynapro *pdynapro = serio_get_drvdata(serio);
+
+	input_get_device(pdynapro->dev);
+	input_unregister_device(pdynapro->dev);
+	serio_close(serio);
+	serio_set_drvdata(serio, NULL);
+	input_put_device(pdynapro->dev);
+	kfree(pdynapro);
+}
+
+/*
+ * dynapro_connect() is the routine that is called when someone adds a
+ * new serio device that supports dynapro protocol and registers it as
+ * an input device. This is usually accomplished using inputattach.
+ */
+
+static int dynapro_connect(struct serio *serio, struct serio_driver *drv)
+{
+	struct dynapro *pdynapro;
+	struct input_dev *input_dev;
+	int err;
+
+	pdynapro = kzalloc_obj(*pdynapro);
+	input_dev = input_allocate_device();
+	if (!pdynapro || !input_dev) {
+		err = -ENOMEM;
+		goto fail1;
+	}
+
+	pdynapro->serio = serio;
+	pdynapro->dev = input_dev;
+	scnprintf(pdynapro->phys, sizeof(pdynapro->phys),
+		  "%s/input0", serio->phys);
+
+	input_dev->name = "Dynapro Serial TouchScreen";
+	input_dev->phys = pdynapro->phys;
+	input_dev->id.bustype = BUS_RS232;
+	input_dev->id.vendor = SERIO_DYNAPRO;
+	input_dev->id.product = 0;
+	input_dev->id.version = 0x0001;
+	input_dev->dev.parent = &serio->dev;
+	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+	input_set_abs_params(pdynapro->dev, ABS_X,
+			     DYNAPRO_MIN_XC, DYNAPRO_MAX_XC, 0, 0);
+	input_set_abs_params(pdynapro->dev, ABS_Y,
+			     DYNAPRO_MIN_YC, DYNAPRO_MAX_YC, 0, 0);
+
+	serio_set_drvdata(serio, pdynapro);
+
+	err = serio_open(serio, drv);
+	if (err)
+		goto fail2;
+
+	err = input_register_device(pdynapro->dev);
+	if (err)
+		goto fail3;
+
+	return 0;
+
+ fail3:	serio_close(serio);
+ fail2:	serio_set_drvdata(serio, NULL);
+ fail1:	input_free_device(input_dev);
+	kfree(pdynapro);
+	return err;
+}
+
+/*
+ * The serio driver structure.
+ */
+
+static const struct serio_device_id dynapro_serio_ids[] = {
+	{
+		.type	= SERIO_RS232,
+		.proto	= SERIO_DYNAPRO,
+		.id	= SERIO_ANY,
+		.extra	= SERIO_ANY,
+	},
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(serio, dynapro_serio_ids);
+
+static struct serio_driver dynapro_drv = {
+	.driver		= {
+		.name	= "dynapro",
+	},
+	.description	= DRIVER_DESC,
+	.id_table	= dynapro_serio_ids,
+	.interrupt	= dynapro_interrupt,
+	.connect	= dynapro_connect,
+	.disconnect	= dynapro_disconnect,
+};
+
+module_serio_driver(dynapro_drv);