Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 255 insertions, 0 deletions

diff --git a/drivers/hwmon/ds620.c b/drivers/hwmon/ds620.c
new file mode 100644
index 000000000..25287f0fa
--- /dev/null
+++ b/drivers/hwmon/ds620.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  ds620.c - Support for temperature sensor and thermostat DS620
+ *
+ *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
+ *
+ *  based on ds1621.c by Christian W. Zuckschwerdt  <zany@triq.net>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/sysfs.h>
+#include <linux/platform_data/ds620.h>
+
+/*
+ * Many DS620 constants specified below
+ *  15   14   13   12   11   10   09    08
+ * |Done|NVB |THF |TLF |R1  |R0  |AUTOC|1SHOT|
+ *
+ *  07   06   05   04   03   02   01    00
+ * |PO2 |PO1 |A2  |A1  |A0  |    |     |     |
+ */
+#define DS620_REG_CONFIG_DONE		0x8000
+#define DS620_REG_CONFIG_NVB		0x4000
+#define DS620_REG_CONFIG_THF		0x2000
+#define DS620_REG_CONFIG_TLF		0x1000
+#define DS620_REG_CONFIG_R1		0x0800
+#define DS620_REG_CONFIG_R0		0x0400
+#define DS620_REG_CONFIG_AUTOC		0x0200
+#define DS620_REG_CONFIG_1SHOT		0x0100
+#define DS620_REG_CONFIG_PO2		0x0080
+#define DS620_REG_CONFIG_PO1		0x0040
+#define DS620_REG_CONFIG_A2		0x0020
+#define DS620_REG_CONFIG_A1		0x0010
+#define DS620_REG_CONFIG_A0		0x0008
+
+/* The DS620 registers */
+static const u8 DS620_REG_TEMP[3] = {
+	0xAA,			/* input, word, RO */
+	0xA2,			/* min, word, RW */
+	0xA0,			/* max, word, RW */
+};
+
+#define DS620_REG_CONF		0xAC	/* word, RW */
+#define DS620_COM_START		0x51	/* no data */
+#define DS620_COM_STOP		0x22	/* no data */
+
+/* Each client has this additional data */
+struct ds620_data {
+	struct i2c_client *client;
+	struct mutex update_lock;
+	bool valid;		/* true if following fields are valid */
+	unsigned long last_updated;	/* In jiffies */
+
+	s16 temp[3];		/* Register values, word */
+};
+
+static void ds620_init_client(struct i2c_client *client)
+{
+	struct ds620_platform_data *ds620_info = dev_get_platdata(&client->dev);
+	u16 conf, new_conf;
+
+	new_conf = conf =
+	    i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
+
+	/* switch to continuous conversion mode */
+	new_conf &= ~DS620_REG_CONFIG_1SHOT;
+	/* already high at power-on, but don't trust the BIOS! */
+	new_conf |= DS620_REG_CONFIG_PO2;
+	/* thermostat mode according to platform data */
+	if (ds620_info && ds620_info->pomode == 1)
+		new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
+	else if (ds620_info && ds620_info->pomode == 2)
+		new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
+	else
+		new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
+	/* with highest precision */
+	new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;
+
+	if (conf != new_conf)
+		i2c_smbus_write_word_swapped(client, DS620_REG_CONF, new_conf);
+
+	/* start conversion */
+	i2c_smbus_write_byte(client, DS620_COM_START);
+}
+
+static struct ds620_data *ds620_update_client(struct device *dev)
+{
+	struct ds620_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	struct ds620_data *ret = data;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+	    || !data->valid) {
+		int i;
+		int res;
+
+		dev_dbg(&client->dev, "Starting ds620 update\n");
+
+		for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
+			res = i2c_smbus_read_word_swapped(client,
+							  DS620_REG_TEMP[i]);
+			if (res < 0) {
+				ret = ERR_PTR(res);
+				goto abort;
+			}
+
+			data->temp[i] = res;
+		}
+
+		data->last_updated = jiffies;
+		data->valid = true;
+	}
+abort:
+	mutex_unlock(&data->update_lock);
+
+	return ret;
+}
+
+static ssize_t temp_show(struct device *dev, struct device_attribute *da,
+			 char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ds620_data *data = ds620_update_client(dev);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
+}
+
+static ssize_t temp_store(struct device *dev, struct device_attribute *da,
+			  const char *buf, size_t count)
+{
+	int res;
+	long val;
+
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ds620_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+
+	res = kstrtol(buf, 10, &val);
+
+	if (res)
+		return res;
+
+	val = (clamp_val(val, -128000, 128000) * 10 / 625) * 8;
+
+	mutex_lock(&data->update_lock);
+	data->temp[attr->index] = val;
+	i2c_smbus_write_word_swapped(client, DS620_REG_TEMP[attr->index],
+				     data->temp[attr->index]);
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+static ssize_t alarm_show(struct device *dev, struct device_attribute *da,
+			  char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ds620_data *data = ds620_update_client(dev);
+	struct i2c_client *client;
+	u16 conf, new_conf;
+	int res;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	client = data->client;
+
+	/* reset alarms if necessary */
+	res = i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
+	if (res < 0)
+		return res;
+
+	new_conf = conf = res;
+	new_conf &= ~attr->index;
+	if (conf != new_conf) {
+		res = i2c_smbus_write_word_swapped(client, DS620_REG_CONF,
+						   new_conf);
+		if (res < 0)
+			return res;
+	}
+
+	return sprintf(buf, "%d\n", !!(conf & attr->index));
+}
+
+static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
+static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
+static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
+static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS620_REG_CONFIG_TLF);
+static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS620_REG_CONFIG_THF);
+
+static struct attribute *ds620_attrs[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_max.dev_attr.attr,
+	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(ds620);
+
+static int ds620_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct device *hwmon_dev;
+	struct ds620_data *data;
+
+	data = devm_kzalloc(dev, sizeof(struct ds620_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	mutex_init(&data->update_lock);
+
+	/* Initialize the DS620 chip */
+	ds620_init_client(client);
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
+							   data, ds620_groups);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ds620_id[] = {
+	{ .name = "ds620" },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, ds620_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ds620_driver = {
+	.driver = {
+		   .name = "ds620",
+	},
+	.probe = ds620_probe,
+	.id_table = ds620_id,
+};
+
+module_i2c_driver(ds620_driver);
+
+MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
+MODULE_DESCRIPTION("DS620 driver");
+MODULE_LICENSE("GPL");