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, 243 insertions, 0 deletions

diff --git a/drivers/iio/temperature/tmp117.c b/drivers/iio/temperature/tmp117.c
new file mode 100644
index 000000000..74cb8d62b
--- /dev/null
+++ b/drivers/iio/temperature/tmp117.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Digital temperature sensor with integrated Non-volatile memory
+ * Copyright (c) 2021 Puranjay Mohan <puranjay12@gmail.com>
+ *
+ * Driver for the Texas Instruments TMP117 Temperature Sensor
+ * (7-bit I2C slave address (0x48 - 0x4B), changeable via ADD pins)
+ *
+ * Note: This driver assumes that the sensor has been calibrated beforehand.
+ */
+
+#include <linux/array_size.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/limits.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/iio/iio.h>
+
+#define TMP117_REG_TEMP			0x0
+#define TMP117_REG_CFGR			0x1
+#define TMP117_REG_HIGH_LIM		0x2
+#define TMP117_REG_LOW_LIM		0x3
+#define TMP117_REG_EEPROM_UL		0x4
+#define TMP117_REG_EEPROM1		0x5
+#define TMP117_REG_EEPROM2		0x6
+#define TMP117_REG_TEMP_OFFSET		0x7
+#define TMP117_REG_EEPROM3		0x8
+#define TMP117_REG_DEVICE_ID		0xF
+
+#define TMP117_RESOLUTION_10UC		78125
+#define MICRODEGREE_PER_10MILLIDEGREE	10000
+
+#define TMP116_DEVICE_ID		0x1116
+#define TMP117_DEVICE_ID		0x0117
+#define TMP119_DEVICE_ID		0x2117
+
+struct tmp117_data {
+	struct i2c_client *client;
+	s16 calibbias;
+};
+
+struct tmp11x_info {
+	const char *name;
+	struct iio_chan_spec const *channels;
+	int num_channels;
+};
+
+static int tmp117_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *channel, int *val,
+			   int *val2, long mask)
+{
+	struct tmp117_data *data = iio_priv(indio_dev);
+	s32 ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = i2c_smbus_read_word_swapped(data->client,
+						  TMP117_REG_TEMP);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(ret, 15);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_CALIBBIAS:
+		ret = i2c_smbus_read_word_swapped(data->client,
+						  TMP117_REG_TEMP_OFFSET);
+		if (ret < 0)
+			return ret;
+		*val = sign_extend32(ret, 15);
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		/*
+		 * Conversion from 10s of uC to mC
+		 * as IIO reports temperature in mC
+		 */
+		*val = TMP117_RESOLUTION_10UC / MICRODEGREE_PER_10MILLIDEGREE;
+		*val2 = (TMP117_RESOLUTION_10UC %
+					MICRODEGREE_PER_10MILLIDEGREE) * 100;
+
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int tmp117_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec
+			    const *channel, int val, int val2, long mask)
+{
+	struct tmp117_data *data = iio_priv(indio_dev);
+	s16 off;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBBIAS:
+		off = clamp_t(int, val, S16_MIN, S16_MAX);
+		if (off == data->calibbias)
+			return 0;
+		data->calibbias = off;
+		return i2c_smbus_write_word_swapped(data->client,
+						TMP117_REG_TEMP_OFFSET, off);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec tmp117_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_CALIBBIAS) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+	},
+};
+
+static const struct iio_chan_spec tmp116_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+	},
+};
+
+static const struct tmp11x_info tmp116_channels_info = {
+	.name = "tmp116",
+	.channels = tmp116_channels,
+	.num_channels = ARRAY_SIZE(tmp116_channels)
+};
+
+static const struct tmp11x_info tmp117_channels_info = {
+	.name = "tmp117",
+	.channels = tmp117_channels,
+	.num_channels = ARRAY_SIZE(tmp117_channels)
+};
+
+static const struct tmp11x_info tmp119_channels_info = {
+	.name = "tmp119",
+	.channels = tmp117_channels,
+	.num_channels = ARRAY_SIZE(tmp117_channels)
+};
+
+static const struct iio_info tmp117_info = {
+	.read_raw = tmp117_read_raw,
+	.write_raw = tmp117_write_raw,
+};
+
+static int tmp117_probe(struct i2c_client *client)
+{
+	const struct tmp11x_info *match_data;
+	struct tmp117_data *data;
+	struct iio_dev *indio_dev;
+	int dev_id;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	ret = devm_regulator_get_enable(&client->dev, "vcc");
+	if (ret)
+		return ret;
+
+	fsleep(1500);
+
+	dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
+	if (dev_id < 0)
+		return dev_id;
+
+	switch (dev_id) {
+	case TMP116_DEVICE_ID:
+		match_data = &tmp116_channels_info;
+		break;
+	case TMP117_DEVICE_ID:
+		match_data = &tmp117_channels_info;
+		break;
+	case TMP119_DEVICE_ID:
+		match_data = &tmp119_channels_info;
+		break;
+	default:
+		dev_info(&client->dev,
+			 "Unknown device id (0x%x), use fallback compatible\n",
+			 dev_id);
+		match_data = i2c_get_match_data(client);
+	}
+
+	if (!match_data)
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "Failed to identify unsupported device\n");
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	data->calibbias = 0;
+
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &tmp117_info;
+	indio_dev->channels = match_data->channels;
+	indio_dev->num_channels = match_data->num_channels;
+	indio_dev->name = match_data->name;
+
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct of_device_id tmp117_of_match[] = {
+	{ .compatible = "ti,tmp116", .data = &tmp116_channels_info },
+	{ .compatible = "ti,tmp117", .data = &tmp117_channels_info },
+	{ .compatible = "ti,tmp119", .data = &tmp119_channels_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tmp117_of_match);
+
+static const struct i2c_device_id tmp117_id[] = {
+	{ .name = "tmp116", .driver_data = (kernel_ulong_t)&tmp116_channels_info },
+	{ .name = "tmp117", .driver_data = (kernel_ulong_t)&tmp117_channels_info },
+	{ .name = "tmp119", .driver_data = (kernel_ulong_t)&tmp119_channels_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tmp117_id);
+
+static struct i2c_driver tmp117_driver = {
+	.driver = {
+		.name	= "tmp117",
+		.of_match_table = tmp117_of_match,
+	},
+	.probe		= tmp117_probe,
+	.id_table	= tmp117_id,
+};
+module_i2c_driver(tmp117_driver);
+
+MODULE_AUTHOR("Puranjay Mohan <puranjay12@gmail.com>");
+MODULE_DESCRIPTION("TI TMP117 Temperature sensor driver");
+MODULE_LICENSE("GPL");