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, 299 insertions, 0 deletions

diff --git a/drivers/misc/ds1682.c b/drivers/misc/ds1682.c
new file mode 100644
index 000000000..4500d7d0e
--- /dev/null
+++ b/drivers/misc/ds1682.c
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
+ *
+ * Written by: Grant Likely <grant.likely@secretlab.ca>
+ *
+ * Copyright (C) 2007 Secret Lab Technologies Ltd.
+ */
+
+/*
+ * The DS1682 elapsed timer recorder is a simple device that implements
+ * one elapsed time counter, one event counter, an alarm signal and 10
+ * bytes of general purpose EEPROM.
+ *
+ * This driver provides access to the DS1682 counters and user data via
+ * the sysfs.  The following attributes are added to the device node:
+ *     elapsed_time (u32): Total elapsed event time in ms resolution
+ *     alarm_time (u32): When elapsed time exceeds the value in alarm_time,
+ *                       then the alarm pin is asserted.
+ *     event_count (u16): number of times the event pin has gone low.
+ *     eeprom (u8[10]): general purpose EEPROM
+ *
+ * Counter registers and user data are both read/write unless the device
+ * has been write protected.  This driver does not support turning off write
+ * protection.  Once write protection is turned on, it is impossible to
+ * turn it off again, so I have left the feature out of this driver to avoid
+ * accidental enabling, but it is trivial to add write protect support.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/nvmem-provider.h>
+#include <linux/sysfs.h>
+#include <linux/ctype.h>
+#include <linux/hwmon-sysfs.h>
+
+/* Device registers */
+#define DS1682_REG_CONFIG		0x00
+#define DS1682_REG_ALARM		0x01
+#define DS1682_REG_ELAPSED		0x05
+#define DS1682_REG_EVT_CNTR		0x09
+#define DS1682_REG_EEPROM		0x0b
+#define DS1682_REG_RESET		0x1d
+#define DS1682_REG_WRITE_DISABLE	0x1e
+#define DS1682_REG_WRITE_MEM_DISABLE	0x1f
+
+#define DS1682_EEPROM_SIZE		10
+
+/*
+ * Generic counter attributes
+ */
+static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
+	struct i2c_client *client = to_i2c_client(dev);
+	unsigned long long val, check;
+	__le32 val_le = 0;
+	int rc;
+
+	dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);
+
+	/* Read the register */
+	rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr,
+					   (u8 *)&val_le);
+	if (rc < 0)
+		return -EIO;
+
+	val = le32_to_cpu(val_le);
+
+	if (sattr->index == DS1682_REG_ELAPSED) {
+		int retries = 5;
+
+		/* Detect and retry when a tick occurs mid-read */
+		do {
+			rc = i2c_smbus_read_i2c_block_data(client, sattr->index,
+							   sattr->nr,
+							   (u8 *)&val_le);
+			if (rc < 0 || retries <= 0)
+				return -EIO;
+
+			check = val;
+			val = le32_to_cpu(val_le);
+			retries--;
+		} while (val != check && val != (check + 1));
+	}
+
+	/* Format the output string and return # of bytes
+	 * Special case: the 32 bit regs are time values with 1/4s
+	 * resolution, scale them up to milliseconds
+	 */
+	return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : val);
+}
+
+static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
+	struct i2c_client *client = to_i2c_client(dev);
+	u64 val;
+	__le32 val_le;
+	int rc;
+
+	dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
+
+	/* Decode input */
+	rc = kstrtoull(buf, 0, &val);
+	if (rc < 0) {
+		dev_dbg(dev, "input string not a number\n");
+		return -EINVAL;
+	}
+
+	/* Special case: the 32 bit regs are time values with 1/4s
+	 * resolution, scale input down to quarter-seconds */
+	if (sattr->nr == 4)
+		do_div(val, 250);
+
+	/* write out the value */
+	val_le = cpu_to_le32(val);
+	rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr,
+					    (u8 *) & val_le);
+	if (rc < 0) {
+		dev_err(dev, "register write failed; reg=0x%x, size=%i\n",
+			sattr->index, sattr->nr);
+		return -EIO;
+	}
+
+	return count;
+}
+
+/*
+ * Simple register attributes
+ */
+static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show,
+			    ds1682_store, 4, DS1682_REG_ELAPSED);
+static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show,
+			    ds1682_store, 4, DS1682_REG_ALARM);
+static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show,
+			    ds1682_store, 2, DS1682_REG_EVT_CNTR);
+
+static const struct attribute_group ds1682_group = {
+	.attrs = (struct attribute *[]) {
+		&sensor_dev_attr_elapsed_time.dev_attr.attr,
+		&sensor_dev_attr_alarm_time.dev_attr.attr,
+		&sensor_dev_attr_event_count.dev_attr.attr,
+		NULL,
+	},
+};
+
+/*
+ * User data attribute
+ */
+static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj,
+				  const struct bin_attribute *attr,
+				  char *buf, loff_t off, size_t count)
+{
+	struct i2c_client *client = kobj_to_i2c_client(kobj);
+	int rc;
+
+	dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
+		buf, off, count);
+
+	rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off,
+					   count, buf);
+	if (rc < 0)
+		return -EIO;
+
+	return count;
+}
+
+static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj,
+				   const struct bin_attribute *attr,
+				   char *buf, loff_t off, size_t count)
+{
+	struct i2c_client *client = kobj_to_i2c_client(kobj);
+
+	dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
+		buf, off, count);
+
+	/* Write out to the device */
+	if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
+					   count, buf) < 0)
+		return -EIO;
+
+	return count;
+}
+
+static const struct bin_attribute ds1682_eeprom_attr = {
+	.attr = {
+		.name = "eeprom",
+		.mode = S_IRUGO | S_IWUSR,
+	},
+	.size = DS1682_EEPROM_SIZE,
+	.read = ds1682_eeprom_read,
+	.write = ds1682_eeprom_write,
+};
+
+static int ds1682_nvmem_read(void *priv, unsigned int offset, void *val,
+			     size_t bytes)
+{
+	struct i2c_client *client = priv;
+	int ret;
+
+	ret = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + offset,
+					    bytes, val);
+	return ret < 0 ? ret : 0;
+}
+
+static int ds1682_nvmem_write(void *priv, unsigned int offset, void *val,
+			      size_t bytes)
+{
+	struct i2c_client *client = priv;
+	int ret;
+
+	ret = i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + offset,
+					     bytes, val);
+	return ret < 0 ? ret : 0;
+}
+
+/*
+ * Called when a ds1682 device is matched with this driver
+ */
+static int ds1682_probe(struct i2c_client *client)
+{
+	struct nvmem_config config = {
+		.dev = &client->dev,
+		.owner = THIS_MODULE,
+		.type = NVMEM_TYPE_EEPROM,
+		.reg_read = ds1682_nvmem_read,
+		.reg_write = ds1682_nvmem_write,
+		.size = DS1682_EEPROM_SIZE,
+		.priv = client,
+	};
+	struct nvmem_device *nvmem;
+	int rc;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_I2C_BLOCK)) {
+		dev_err(&client->dev, "i2c bus does not support the ds1682\n");
+		rc = -ENODEV;
+		goto exit;
+	}
+
+	nvmem = devm_nvmem_register(&client->dev, &config);
+	if (IS_ENABLED(CONFIG_NVMEM) && IS_ERR(nvmem))
+		return PTR_ERR(nvmem);
+
+	rc = sysfs_create_group(&client->dev.kobj, &ds1682_group);
+	if (rc)
+		goto exit;
+
+	rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
+	if (rc)
+		goto exit_bin_attr;
+
+	return 0;
+
+ exit_bin_attr:
+	sysfs_remove_group(&client->dev.kobj, &ds1682_group);
+ exit:
+	return rc;
+}
+
+static void ds1682_remove(struct i2c_client *client)
+{
+	sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
+	sysfs_remove_group(&client->dev.kobj, &ds1682_group);
+}
+
+static const struct i2c_device_id ds1682_id[] = {
+	{ .name = "ds1682" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ds1682_id);
+
+static const struct of_device_id ds1682_of_match[] = {
+	{ .compatible = "dallas,ds1682" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ds1682_of_match);
+
+static struct i2c_driver ds1682_driver = {
+	.driver = {
+		.name = "ds1682",
+		.of_match_table = ds1682_of_match,
+	},
+	.probe = ds1682_probe,
+	.remove = ds1682_remove,
+	.id_table = ds1682_id,
+};
+
+module_i2c_driver(ds1682_driver);
+
+MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
+MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
+MODULE_LICENSE("GPL");