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, 347 insertions, 0 deletions

diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
new file mode 100644
index 000000000..461e39383
--- /dev/null
+++ b/drivers/video/backlight/lcd.c
@@ -0,0 +1,347 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LCD Lowlevel Control Abstraction
+ *
+ * Copyright (C) 2003,2004 Hewlett-Packard Company
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/lcd.h>
+#include <linux/notifier.h>
+#include <linux/ctype.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+static DEFINE_MUTEX(lcd_dev_list_mutex);
+static LIST_HEAD(lcd_dev_list);
+
+static void lcd_notify_blank(struct lcd_device *ld, struct device *display_dev,
+			     int power)
+{
+	guard(mutex)(&ld->ops_lock);
+
+	if (!ld->ops || !ld->ops->set_power)
+		return;
+	if (ld->ops->controls_device && !ld->ops->controls_device(ld, display_dev))
+		return;
+
+	ld->ops->set_power(ld, power);
+}
+
+void lcd_notify_blank_all(struct device *display_dev, int power)
+{
+	struct lcd_device *ld;
+
+	guard(mutex)(&lcd_dev_list_mutex);
+
+	list_for_each_entry(ld, &lcd_dev_list, entry)
+		lcd_notify_blank(ld, display_dev, power);
+}
+EXPORT_SYMBOL(lcd_notify_blank_all);
+
+static void lcd_notify_mode_change(struct lcd_device *ld, struct device *display_dev,
+				   unsigned int width, unsigned int height)
+{
+	guard(mutex)(&ld->ops_lock);
+
+	if (!ld->ops || !ld->ops->set_mode)
+		return;
+	if (ld->ops->controls_device && !ld->ops->controls_device(ld, display_dev))
+		return;
+
+	ld->ops->set_mode(ld, width, height);
+}
+
+void lcd_notify_mode_change_all(struct device *display_dev,
+				unsigned int width, unsigned int height)
+{
+	struct lcd_device *ld;
+
+	guard(mutex)(&lcd_dev_list_mutex);
+
+	list_for_each_entry(ld, &lcd_dev_list, entry)
+		lcd_notify_mode_change(ld, display_dev, width, height);
+}
+EXPORT_SYMBOL(lcd_notify_mode_change_all);
+
+static ssize_t lcd_power_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	int rc;
+	struct lcd_device *ld = to_lcd_device(dev);
+
+	mutex_lock(&ld->ops_lock);
+	if (ld->ops && ld->ops->get_power)
+		rc = sysfs_emit(buf, "%d\n", ld->ops->get_power(ld));
+	else
+		rc = -ENXIO;
+	mutex_unlock(&ld->ops_lock);
+
+	return rc;
+}
+
+static ssize_t lcd_power_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	int rc;
+	struct lcd_device *ld = to_lcd_device(dev);
+	unsigned long power;
+
+	rc = kstrtoul(buf, 0, &power);
+	if (rc)
+		return rc;
+
+	rc = -ENXIO;
+
+	mutex_lock(&ld->ops_lock);
+	if (ld->ops && ld->ops->set_power) {
+		pr_debug("set power to %lu\n", power);
+		ld->ops->set_power(ld, power);
+		rc = count;
+	}
+	mutex_unlock(&ld->ops_lock);
+
+	return rc;
+}
+static DEVICE_ATTR_RW(lcd_power);
+
+static ssize_t contrast_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	int rc = -ENXIO;
+	struct lcd_device *ld = to_lcd_device(dev);
+
+	mutex_lock(&ld->ops_lock);
+	if (ld->ops && ld->ops->get_contrast)
+		rc = sysfs_emit(buf, "%d\n", ld->ops->get_contrast(ld));
+	mutex_unlock(&ld->ops_lock);
+
+	return rc;
+}
+
+static ssize_t contrast_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	int rc;
+	struct lcd_device *ld = to_lcd_device(dev);
+	unsigned long contrast;
+
+	rc = kstrtoul(buf, 0, &contrast);
+	if (rc)
+		return rc;
+
+	rc = -ENXIO;
+
+	mutex_lock(&ld->ops_lock);
+	if (ld->ops && ld->ops->set_contrast) {
+		pr_debug("set contrast to %lu\n", contrast);
+		ld->ops->set_contrast(ld, contrast);
+		rc = count;
+	}
+	mutex_unlock(&ld->ops_lock);
+
+	return rc;
+}
+static DEVICE_ATTR_RW(contrast);
+
+static ssize_t max_contrast_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct lcd_device *ld = to_lcd_device(dev);
+
+	return sysfs_emit(buf, "%d\n", ld->props.max_contrast);
+}
+static DEVICE_ATTR_RO(max_contrast);
+
+static void lcd_device_release(struct device *dev)
+{
+	struct lcd_device *ld = to_lcd_device(dev);
+	kfree(ld);
+}
+
+static struct attribute *lcd_device_attrs[] = {
+	&dev_attr_lcd_power.attr,
+	&dev_attr_contrast.attr,
+	&dev_attr_max_contrast.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(lcd_device);
+
+static const struct class lcd_class = {
+	.name = "lcd",
+	.dev_groups = lcd_device_groups,
+};
+
+/**
+ * lcd_device_register - register a new object of lcd_device class.
+ * @name: the name of the new object(must be the same as the name of the
+ *   respective framebuffer device).
+ * @parent: pointer to the parent's struct device .
+ * @devdata: an optional pointer to be stored in the device. The
+ *   methods may retrieve it by using lcd_get_data(ld).
+ * @ops: the lcd operations structure.
+ *
+ * Creates and registers a new lcd device. Returns either an ERR_PTR()
+ * or a pointer to the newly allocated device.
+ */
+struct lcd_device *lcd_device_register(const char *name, struct device *parent,
+		void *devdata, const struct lcd_ops *ops)
+{
+	struct lcd_device *new_ld;
+	int rc;
+
+	pr_debug("lcd_device_register: name=%s\n", name);
+
+	new_ld = kzalloc_obj(struct lcd_device);
+	if (!new_ld)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&new_ld->ops_lock);
+	mutex_init(&new_ld->update_lock);
+
+	new_ld->dev.class = &lcd_class;
+	new_ld->dev.parent = parent;
+	new_ld->dev.release = lcd_device_release;
+	dev_set_name(&new_ld->dev, "%s", name);
+	dev_set_drvdata(&new_ld->dev, devdata);
+
+	new_ld->ops = ops;
+
+	rc = device_register(&new_ld->dev);
+	if (rc) {
+		put_device(&new_ld->dev);
+		return ERR_PTR(rc);
+	}
+
+	guard(mutex)(&lcd_dev_list_mutex);
+	list_add(&new_ld->entry, &lcd_dev_list);
+
+	return new_ld;
+}
+EXPORT_SYMBOL(lcd_device_register);
+
+/**
+ * lcd_device_unregister - unregisters a object of lcd_device class.
+ * @ld: the lcd device object to be unregistered and freed.
+ *
+ * Unregisters a previously registered via lcd_device_register object.
+ */
+void lcd_device_unregister(struct lcd_device *ld)
+{
+	if (!ld)
+		return;
+
+	guard(mutex)(&lcd_dev_list_mutex);
+	list_del(&ld->entry);
+
+	mutex_lock(&ld->ops_lock);
+	ld->ops = NULL;
+	mutex_unlock(&ld->ops_lock);
+
+	device_unregister(&ld->dev);
+}
+EXPORT_SYMBOL(lcd_device_unregister);
+
+static void devm_lcd_device_release(struct device *dev, void *res)
+{
+	struct lcd_device *lcd = *(struct lcd_device **)res;
+
+	lcd_device_unregister(lcd);
+}
+
+static int devm_lcd_device_match(struct device *dev, void *res, void *data)
+{
+	struct lcd_device **r = res;
+
+	return *r == data;
+}
+
+/**
+ * devm_lcd_device_register - resource managed lcd_device_register()
+ * @dev: the device to register
+ * @name: the name of the device
+ * @parent: a pointer to the parent device
+ * @devdata: an optional pointer to be stored for private driver use
+ * @ops: the lcd operations structure
+ *
+ * @return a struct lcd on success, or an ERR_PTR on error
+ *
+ * Managed lcd_device_register(). The lcd_device returned from this function
+ * are automatically freed on driver detach. See lcd_device_register()
+ * for more information.
+ */
+struct lcd_device *devm_lcd_device_register(struct device *dev,
+		const char *name, struct device *parent,
+		void *devdata, const struct lcd_ops *ops)
+{
+	struct lcd_device **ptr, *lcd;
+
+	ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	lcd = lcd_device_register(name, parent, devdata, ops);
+	if (!IS_ERR(lcd)) {
+		*ptr = lcd;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return lcd;
+}
+EXPORT_SYMBOL(devm_lcd_device_register);
+
+/**
+ * devm_lcd_device_unregister - resource managed lcd_device_unregister()
+ * @dev: the device to unregister
+ * @ld: the lcd device to unregister
+ *
+ * Deallocated a lcd allocated with devm_lcd_device_register(). Normally
+ * this function will not need to be called and the resource management
+ * code will ensure that the resource is freed.
+ */
+void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld)
+{
+	int rc;
+
+	rc = devres_release(dev, devm_lcd_device_release,
+				devm_lcd_device_match, ld);
+	WARN_ON(rc);
+}
+EXPORT_SYMBOL(devm_lcd_device_unregister);
+
+
+static void __exit lcd_class_exit(void)
+{
+	class_unregister(&lcd_class);
+}
+
+static int __init lcd_class_init(void)
+{
+	int ret;
+
+	ret = class_register(&lcd_class);
+	if (ret) {
+		pr_warn("Unable to create backlight class; errno = %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * if this is compiled into the kernel, we need to ensure that the
+ * class is registered before users of the class try to register lcd's
+ */
+postcore_initcall(lcd_class_init);
+module_exit(lcd_class_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
+MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");