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, 411 insertions, 0 deletions

diff --git a/drivers/iio/temperature/tmp006.c b/drivers/iio/temperature/tmp006.c
new file mode 100644
index 000000000..d9f6449ec
--- /dev/null
+++ b/drivers/iio/temperature/tmp006.c
@@ -0,0 +1,411 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * tmp006.c - Support for TI TMP006 IR thermopile sensor
+ *
+ * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * Driver for the Texas Instruments I2C 16-bit IR thermopile sensor
+ *
+ * (7-bit I2C slave address 0x40, changeable via ADR pins)
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/bitops.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#define TMP006_VOBJECT 0x00
+#define TMP006_TAMBIENT 0x01
+#define TMP006_CONFIG 0x02
+#define TMP006_MANUFACTURER_ID 0xfe
+#define TMP006_DEVICE_ID 0xff
+
+#define TMP006_TAMBIENT_SHIFT 2
+
+#define TMP006_CONFIG_RESET BIT(15)
+#define TMP006_CONFIG_DRDY_EN BIT(8)
+#define TMP006_CONFIG_DRDY BIT(7)
+
+#define TMP006_CONFIG_MOD_MASK GENMASK(14, 12)
+
+#define TMP006_CONFIG_CR_MASK GENMASK(11, 9)
+#define TMP006_CONFIG_CR_SHIFT 9
+
+#define TMP006_MANUFACTURER_MAGIC 0x5449
+#define TMP006_DEVICE_MAGIC 0x0067
+
+struct tmp006_data {
+	struct i2c_client *client;
+	u16 config;
+	struct iio_trigger *drdy_trig;
+};
+
+static int tmp006_read_measurement(struct tmp006_data *data, u8 reg)
+{
+	s32 ret;
+	int tries = 50;
+
+	while (tries-- > 0) {
+		ret = i2c_smbus_read_word_swapped(data->client,
+			TMP006_CONFIG);
+		if (ret < 0)
+			return ret;
+		if (ret & TMP006_CONFIG_DRDY)
+			break;
+		msleep(100);
+	}
+
+	if (tries < 0)
+		return -EIO;
+
+	return i2c_smbus_read_word_swapped(data->client, reg);
+}
+
+static const int tmp006_freqs[5][2] = { {4, 0}, {2, 0}, {1, 0},
+					{0, 500000}, {0, 250000} };
+
+static int tmp006_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *channel, int *val,
+			    int *val2, long mask)
+{
+	struct tmp006_data *data = iio_priv(indio_dev);
+	s32 ret;
+	int cr;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (channel->type == IIO_VOLTAGE) {
+			/* LSB is 156.25 nV */
+			if (!iio_device_claim_direct(indio_dev))
+				return -EBUSY;
+
+			ret = tmp006_read_measurement(data, TMP006_VOBJECT);
+			iio_device_release_direct(indio_dev);
+			if (ret < 0)
+				return ret;
+
+			*val = sign_extend32(ret, 15);
+		} else if (channel->type == IIO_TEMP) {
+			/* LSB is 0.03125 degrees Celsius */
+			if (!iio_device_claim_direct(indio_dev))
+				return -EBUSY;
+
+			ret = tmp006_read_measurement(data, TMP006_TAMBIENT);
+			iio_device_release_direct(indio_dev);
+			if (ret < 0)
+				return ret;
+
+			*val = sign_extend32(ret, 15) >> TMP006_TAMBIENT_SHIFT;
+		} else {
+			break;
+		}
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		if (channel->type == IIO_VOLTAGE) {
+			*val = 0;
+			*val2 = 156250;
+		} else if (channel->type == IIO_TEMP) {
+			*val = 31;
+			*val2 = 250000;
+		} else {
+			break;
+		}
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		cr = (data->config & TMP006_CONFIG_CR_MASK)
+			>> TMP006_CONFIG_CR_SHIFT;
+		*val = tmp006_freqs[cr][0];
+		*val2 = tmp006_freqs[cr][1];
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static int tmp006_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val,
+			    int val2,
+			    long mask)
+{
+	struct tmp006_data *data = iio_priv(indio_dev);
+	int ret, i;
+
+	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
+		return -EINVAL;
+
+	for (i = 0; i < ARRAY_SIZE(tmp006_freqs); i++)
+		if ((val == tmp006_freqs[i][0]) &&
+		    (val2 == tmp006_freqs[i][1])) {
+			if (!iio_device_claim_direct(indio_dev))
+				return -EBUSY;
+
+			data->config &= ~TMP006_CONFIG_CR_MASK;
+			data->config |= i << TMP006_CONFIG_CR_SHIFT;
+
+			ret = i2c_smbus_write_word_swapped(data->client,
+							   TMP006_CONFIG,
+							   data->config);
+
+			iio_device_release_direct(indio_dev);
+			return ret;
+		}
+	return -EINVAL;
+}
+
+static IIO_CONST_ATTR(sampling_frequency_available, "4 2 1 0.5 0.25");
+
+static struct attribute *tmp006_attributes[] = {
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group tmp006_attribute_group = {
+	.attrs = tmp006_attributes,
+};
+
+static const struct iio_chan_spec tmp006_channels[] = {
+	{
+		.type = IIO_VOLTAGE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_BE,
+		}
+	},
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.scan_index = 1,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 14,
+			.storagebits = 16,
+			.shift = TMP006_TAMBIENT_SHIFT,
+			.endianness = IIO_BE,
+		}
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(2),
+};
+
+static const struct iio_info tmp006_info = {
+	.read_raw = tmp006_read_raw,
+	.write_raw = tmp006_write_raw,
+	.attrs = &tmp006_attribute_group,
+};
+
+static bool tmp006_check_identification(struct i2c_client *client)
+{
+	int mid, did;
+
+	mid = i2c_smbus_read_word_swapped(client, TMP006_MANUFACTURER_ID);
+	if (mid < 0)
+		return false;
+
+	did = i2c_smbus_read_word_swapped(client, TMP006_DEVICE_ID);
+	if (did < 0)
+		return false;
+
+	return mid == TMP006_MANUFACTURER_MAGIC && did == TMP006_DEVICE_MAGIC;
+}
+
+static int tmp006_power(struct device *dev, bool up)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct tmp006_data *data = iio_priv(indio_dev);
+
+	if (up)
+		data->config |= TMP006_CONFIG_MOD_MASK;
+	else
+		data->config &= ~TMP006_CONFIG_MOD_MASK;
+
+	return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
+		data->config);
+}
+
+static void tmp006_powerdown_cleanup(void *dev)
+{
+	tmp006_power(dev, false);
+}
+
+static irqreturn_t tmp006_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct tmp006_data *data = iio_priv(indio_dev);
+	struct {
+		s16 channels[2];
+		aligned_s64 ts;
+	} scan = { };
+	s32 ret;
+
+	ret = i2c_smbus_read_word_data(data->client, TMP006_VOBJECT);
+	if (ret < 0)
+		goto err;
+	scan.channels[0] = ret;
+
+	ret = i2c_smbus_read_word_data(data->client, TMP006_TAMBIENT);
+	if (ret < 0)
+		goto err;
+	scan.channels[1] = ret;
+
+	iio_push_to_buffers_with_ts(indio_dev, &scan, sizeof(scan),
+				    iio_get_time_ns(indio_dev));
+err:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
+static int tmp006_set_trigger_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct tmp006_data *data = iio_priv(indio_dev);
+
+	if (state)
+		data->config |= TMP006_CONFIG_DRDY_EN;
+	else
+		data->config &= ~TMP006_CONFIG_DRDY_EN;
+
+	return i2c_smbus_write_word_swapped(data->client, TMP006_CONFIG,
+					    data->config);
+}
+
+static const struct iio_trigger_ops tmp006_trigger_ops = {
+	.set_trigger_state = tmp006_set_trigger_state,
+};
+
+static const unsigned long tmp006_scan_masks[] = { 0x3, 0 };
+
+static int tmp006_probe(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev;
+	struct tmp006_data *data;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	if (!tmp006_check_identification(client)) {
+		dev_err(&client->dev, "no TMP006 sensor\n");
+		return -ENODEV;
+	}
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+
+	indio_dev->name = dev_name(&client->dev);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &tmp006_info;
+
+	indio_dev->channels = tmp006_channels;
+	indio_dev->num_channels = ARRAY_SIZE(tmp006_channels);
+	indio_dev->available_scan_masks = tmp006_scan_masks;
+
+	ret = i2c_smbus_read_word_swapped(data->client, TMP006_CONFIG);
+	if (ret < 0)
+		return ret;
+	data->config = ret;
+
+	if ((ret & TMP006_CONFIG_MOD_MASK) != TMP006_CONFIG_MOD_MASK) {
+		ret = tmp006_power(&client->dev, true);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = devm_add_action_or_reset(&client->dev, tmp006_powerdown_cleanup,
+				       &client->dev);
+	if (ret < 0)
+		return ret;
+
+	if (client->irq > 0) {
+		data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
+							 "%s-dev%d",
+							 indio_dev->name,
+							 iio_device_id(indio_dev));
+		if (!data->drdy_trig)
+			return -ENOMEM;
+
+		data->drdy_trig->ops = &tmp006_trigger_ops;
+		iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
+		ret = devm_iio_trigger_register(&client->dev, data->drdy_trig);
+		if (ret)
+			return ret;
+
+		indio_dev->trig = iio_trigger_get(data->drdy_trig);
+
+		ret = devm_request_irq(&client->dev, client->irq,
+				       iio_trigger_generic_data_rdy_poll,
+				       IRQF_NO_THREAD, "tmp006_irq",
+				       data->drdy_trig);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
+					      tmp006_trigger_handler, NULL);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int tmp006_suspend(struct device *dev)
+{
+	return tmp006_power(dev, false);
+}
+
+static int tmp006_resume(struct device *dev)
+{
+	return tmp006_power(dev, true);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(tmp006_pm_ops, tmp006_suspend, tmp006_resume);
+
+static const struct of_device_id tmp006_of_match[] = {
+	{ .compatible = "ti,tmp006" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tmp006_of_match);
+
+static const struct i2c_device_id tmp006_id[] = {
+	{ .name = "tmp006" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tmp006_id);
+
+static struct i2c_driver tmp006_driver = {
+	.driver = {
+		.name	= "tmp006",
+		.of_match_table = tmp006_of_match,
+		.pm	= pm_sleep_ptr(&tmp006_pm_ops),
+	},
+	.probe = tmp006_probe,
+	.id_table = tmp006_id,
+};
+module_i2c_driver(tmp006_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("TI TMP006 IR thermopile sensor driver");
+MODULE_LICENSE("GPL");