Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1111 insertions, 0 deletions

diff --git a/lib/kobject.c b/lib/kobject.c
new file mode 100644
index 000000000..e7b010a98
--- /dev/null
+++ b/lib/kobject.c
@@ -0,0 +1,1111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kobject.c - library routines for handling generic kernel objects
+ *
+ * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
+ * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (c) 2006-2007 Novell Inc.
+ *
+ * Please see the file Documentation/core-api/kobject.rst for critical information
+ * about using the kobject interface.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/export.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+
+/**
+ * kobject_namespace() - Return @kobj's namespace tag.
+ * @kobj: kobject in question
+ *
+ * Returns namespace tag of @kobj if its parent has namespace ops enabled
+ * and thus @kobj should have a namespace tag associated with it.  Returns
+ * %NULL otherwise.
+ */
+const struct ns_common *kobject_namespace(const struct kobject *kobj)
+{
+	const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
+
+	if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
+		return NULL;
+
+	return kobj->ktype->namespace(kobj);
+}
+
+/**
+ * kobject_get_ownership() - Get sysfs ownership data for @kobj.
+ * @kobj: kobject in question
+ * @uid: kernel user ID for sysfs objects
+ * @gid: kernel group ID for sysfs objects
+ *
+ * Returns initial uid/gid pair that should be used when creating sysfs
+ * representation of given kobject. Normally used to adjust ownership of
+ * objects in a container.
+ */
+void kobject_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
+{
+	*uid = GLOBAL_ROOT_UID;
+	*gid = GLOBAL_ROOT_GID;
+
+	if (kobj->ktype->get_ownership)
+		kobj->ktype->get_ownership(kobj, uid, gid);
+}
+
+static bool kobj_ns_type_is_valid(enum kobj_ns_type type)
+{
+	if ((type <= KOBJ_NS_TYPE_NONE) || (type >= KOBJ_NS_TYPES))
+		return false;
+
+	return true;
+}
+
+static int create_dir(struct kobject *kobj)
+{
+	const struct kobj_type *ktype = get_ktype(kobj);
+	const struct kobj_ns_type_operations *ops;
+	int error;
+
+	error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
+	if (error)
+		return error;
+
+	if (ktype) {
+		error = sysfs_create_groups(kobj, ktype->default_groups);
+		if (error) {
+			sysfs_remove_dir(kobj);
+			return error;
+		}
+	}
+
+	/*
+	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
+	 * extra reference so that it stays until @kobj is gone.
+	 */
+	sysfs_get(kobj->sd);
+
+	/*
+	 * If @kobj has ns_ops, its children need to be filtered based on
+	 * their namespace tags.  Enable namespace support on @kobj->sd.
+	 */
+	ops = kobj_child_ns_ops(kobj);
+	if (ops) {
+		BUG_ON(!kobj_ns_type_is_valid(ops->type));
+		BUG_ON(!kobj_ns_type_registered(ops->type));
+
+		sysfs_enable_ns(kobj->sd);
+	}
+
+	return 0;
+}
+
+static int get_kobj_path_length(const struct kobject *kobj)
+{
+	int length = 1;
+	const struct kobject *parent = kobj;
+
+	/* walk up the ancestors until we hit the one pointing to the
+	 * root.
+	 * Add 1 to strlen for leading '/' of each level.
+	 */
+	do {
+		if (kobject_name(parent) == NULL)
+			return 0;
+		length += strlen(kobject_name(parent)) + 1;
+		parent = parent->parent;
+	} while (parent);
+	return length;
+}
+
+static int fill_kobj_path(const struct kobject *kobj, char *path, int length)
+{
+	const struct kobject *parent;
+
+	--length;
+	for (parent = kobj; parent; parent = parent->parent) {
+		int cur = strlen(kobject_name(parent));
+		/* back up enough to print this name with '/' */
+		length -= cur;
+		if (length <= 0)
+			return -EINVAL;
+		memcpy(path + length, kobject_name(parent), cur);
+		*(path + --length) = '/';
+	}
+
+	pr_debug("'%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
+		 kobj, __func__, path);
+
+	return 0;
+}
+
+/**
+ * kobject_get_path() - Allocate memory and fill in the path for @kobj.
+ * @kobj:	kobject in question, with which to build the path
+ * @gfp_mask:	the allocation type used to allocate the path
+ *
+ * Return: The newly allocated memory, caller must free with kfree().
+ */
+char *kobject_get_path(const struct kobject *kobj, gfp_t gfp_mask)
+{
+	char *path;
+	int len;
+
+retry:
+	len = get_kobj_path_length(kobj);
+	if (len == 0)
+		return NULL;
+	path = kzalloc(len, gfp_mask);
+	if (!path)
+		return NULL;
+	if (fill_kobj_path(kobj, path, len)) {
+		kfree(path);
+		goto retry;
+	}
+
+	return path;
+}
+EXPORT_SYMBOL_GPL(kobject_get_path);
+
+/* add the kobject to its kset's list */
+static void kobj_kset_join(struct kobject *kobj)
+{
+	if (!kobj->kset)
+		return;
+
+	kset_get(kobj->kset);
+	spin_lock(&kobj->kset->list_lock);
+	list_add_tail(&kobj->entry, &kobj->kset->list);
+	spin_unlock(&kobj->kset->list_lock);
+}
+
+/* remove the kobject from its kset's list */
+static void kobj_kset_leave(struct kobject *kobj)
+{
+	if (!kobj->kset)
+		return;
+
+	spin_lock(&kobj->kset->list_lock);
+	list_del_init(&kobj->entry);
+	spin_unlock(&kobj->kset->list_lock);
+	kset_put(kobj->kset);
+}
+
+static void kobject_init_internal(struct kobject *kobj)
+{
+	if (!kobj)
+		return;
+	kref_init(&kobj->kref);
+	INIT_LIST_HEAD(&kobj->entry);
+	kobj->state_in_sysfs = 0;
+	kobj->state_add_uevent_sent = 0;
+	kobj->state_remove_uevent_sent = 0;
+	kobj->state_initialized = 1;
+}
+
+
+static int kobject_add_internal(struct kobject *kobj)
+{
+	int error = 0;
+	struct kobject *parent;
+
+	if (!kobj)
+		return -ENOENT;
+
+	if (!kobj->name || !kobj->name[0]) {
+		WARN(1,
+		     "kobject: (%p): attempted to be registered with empty name!\n",
+		     kobj);
+		return -EINVAL;
+	}
+
+	parent = kobject_get(kobj->parent);
+
+	/* join kset if set, use it as parent if we do not already have one */
+	if (kobj->kset) {
+		if (!parent)
+			parent = kobject_get(&kobj->kset->kobj);
+		kobj_kset_join(kobj);
+		kobj->parent = parent;
+	}
+
+	pr_debug("'%s' (%p): %s: parent: '%s', set: '%s'\n",
+		 kobject_name(kobj), kobj, __func__,
+		 parent ? kobject_name(parent) : "<NULL>",
+		 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
+
+	error = create_dir(kobj);
+	if (error) {
+		kobj_kset_leave(kobj);
+		kobject_put(parent);
+		kobj->parent = NULL;
+
+		/* be noisy on error issues */
+		if (error == -EEXIST)
+			pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
+			       __func__, kobject_name(kobj));
+		else
+			pr_err("%s failed for %s (error: %d parent: %s)\n",
+			       __func__, kobject_name(kobj), error,
+			       parent ? kobject_name(parent) : "'none'");
+	} else
+		kobj->state_in_sysfs = 1;
+
+	return error;
+}
+
+/**
+ * kobject_set_name_vargs() - Set the name of a kobject.
+ * @kobj: struct kobject to set the name of
+ * @fmt: format string used to build the name
+ * @vargs: vargs to format the string.
+ */
+int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
+				  va_list vargs)
+{
+	const char *s;
+
+	if (kobj->name && !fmt)
+		return 0;
+
+	s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
+	if (!s)
+		return -ENOMEM;
+
+	/*
+	 * ewww... some of these buggers have '/' in the name ... If
+	 * that's the case, we need to make sure we have an actual
+	 * allocated copy to modify, since kvasprintf_const may have
+	 * returned something from .rodata.
+	 */
+	if (strchr(s, '/')) {
+		char *t;
+
+		t = kstrdup(s, GFP_KERNEL);
+		kfree_const(s);
+		if (!t)
+			return -ENOMEM;
+		s = strreplace(t, '/', '!');
+	}
+	kfree_const(kobj->name);
+	kobj->name = s;
+
+	return 0;
+}
+
+/**
+ * kobject_set_name() - Set the name of a kobject.
+ * @kobj: struct kobject to set the name of
+ * @fmt: format string used to build the name
+ *
+ * This sets the name of the kobject.  If you have already added the
+ * kobject to the system, you must call kobject_rename() in order to
+ * change the name of the kobject.
+ */
+int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
+{
+	va_list vargs;
+	int retval;
+
+	va_start(vargs, fmt);
+	retval = kobject_set_name_vargs(kobj, fmt, vargs);
+	va_end(vargs);
+
+	return retval;
+}
+EXPORT_SYMBOL(kobject_set_name);
+
+/**
+ * kobject_init() - Initialize a kobject structure.
+ * @kobj: pointer to the kobject to initialize
+ * @ktype: pointer to the ktype for this kobject.
+ *
+ * This function will properly initialize a kobject such that it can then
+ * be passed to the kobject_add() call.
+ *
+ * After this function is called, the kobject MUST be cleaned up by a call
+ * to kobject_put(), not by a call to kfree directly to ensure that all of
+ * the memory is cleaned up properly.
+ */
+void kobject_init(struct kobject *kobj, const struct kobj_type *ktype)
+{
+	char *err_str;
+
+	if (!kobj) {
+		err_str = "invalid kobject pointer!";
+		goto error;
+	}
+	if (!ktype) {
+		err_str = "must have a ktype to be initialized properly!\n";
+		goto error;
+	}
+	if (kobj->state_initialized) {
+		/* do not error out as sometimes we can recover */
+		pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
+		       kobj);
+		dump_stack_lvl(KERN_ERR);
+	}
+
+	kobject_init_internal(kobj);
+	kobj->ktype = ktype;
+	return;
+
+error:
+	pr_err("kobject (%p): %s\n", kobj, err_str);
+	dump_stack_lvl(KERN_ERR);
+}
+EXPORT_SYMBOL(kobject_init);
+
+static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
+					   struct kobject *parent,
+					   const char *fmt, va_list vargs)
+{
+	int retval;
+
+	retval = kobject_set_name_vargs(kobj, fmt, vargs);
+	if (retval) {
+		pr_err("can not set name properly!\n");
+		return retval;
+	}
+	kobj->parent = parent;
+	return kobject_add_internal(kobj);
+}
+
+/**
+ * kobject_add() - The main kobject add function.
+ * @kobj: the kobject to add
+ * @parent: pointer to the parent of the kobject.
+ * @fmt: format to name the kobject with.
+ *
+ * The kobject name is set and added to the kobject hierarchy in this
+ * function.
+ *
+ * If @parent is set, then the parent of the @kobj will be set to it.
+ * If @parent is NULL, then the parent of the @kobj will be set to the
+ * kobject associated with the kset assigned to this kobject.  If no kset
+ * is assigned to the kobject, then the kobject will be located in the
+ * root of the sysfs tree.
+ *
+ * Note, no "add" uevent will be created with this call, the caller should set
+ * up all of the necessary sysfs files for the object and then call
+ * kobject_uevent() with the UEVENT_ADD parameter to ensure that
+ * userspace is properly notified of this kobject's creation.
+ *
+ * Return: If this function returns an error, kobject_put() must be
+ *         called to properly clean up the memory associated with the
+ *         object.  Under no instance should the kobject that is passed
+ *         to this function be directly freed with a call to kfree(),
+ *         that can leak memory.
+ *
+ *         If this function returns success, kobject_put() must also be called
+ *         in order to properly clean up the memory associated with the object.
+ *
+ *         In short, once this function is called, kobject_put() MUST be called
+ *         when the use of the object is finished in order to properly free
+ *         everything.
+ */
+int kobject_add(struct kobject *kobj, struct kobject *parent,
+		const char *fmt, ...)
+{
+	va_list args;
+	int retval;
+
+	if (!kobj)
+		return -EINVAL;
+
+	if (!kobj->state_initialized) {
+		pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
+		       kobject_name(kobj), kobj);
+		dump_stack_lvl(KERN_ERR);
+		return -EINVAL;
+	}
+	va_start(args, fmt);
+	retval = kobject_add_varg(kobj, parent, fmt, args);
+	va_end(args);
+
+	return retval;
+}
+EXPORT_SYMBOL(kobject_add);
+
+/**
+ * kobject_init_and_add() - Initialize a kobject structure and add it to
+ *                          the kobject hierarchy.
+ * @kobj: pointer to the kobject to initialize
+ * @ktype: pointer to the ktype for this kobject.
+ * @parent: pointer to the parent of this kobject.
+ * @fmt: the name of the kobject.
+ *
+ * This function combines the call to kobject_init() and kobject_add().
+ *
+ * If this function returns an error, kobject_put() must be called to
+ * properly clean up the memory associated with the object.  This is the
+ * same type of error handling after a call to kobject_add() and kobject
+ * lifetime rules are the same here.
+ */
+int kobject_init_and_add(struct kobject *kobj, const struct kobj_type *ktype,
+			 struct kobject *parent, const char *fmt, ...)
+{
+	va_list args;
+	int retval;
+
+	kobject_init(kobj, ktype);
+
+	va_start(args, fmt);
+	retval = kobject_add_varg(kobj, parent, fmt, args);
+	va_end(args);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(kobject_init_and_add);
+
+/**
+ * kobject_rename() - Change the name of an object.
+ * @kobj: object in question.
+ * @new_name: object's new name
+ *
+ * It is the responsibility of the caller to provide mutual
+ * exclusion between two different calls of kobject_rename
+ * on the same kobject and to ensure that new_name is valid and
+ * won't conflict with other kobjects.
+ */
+int kobject_rename(struct kobject *kobj, const char *new_name)
+{
+	int error = 0;
+	const char *devpath = NULL;
+	const char *dup_name = NULL, *name;
+	char *devpath_string = NULL;
+	char *envp[2];
+
+	kobj = kobject_get(kobj);
+	if (!kobj)
+		return -EINVAL;
+	if (!kobj->parent) {
+		kobject_put(kobj);
+		return -EINVAL;
+	}
+
+	devpath = kobject_get_path(kobj, GFP_KERNEL);
+	if (!devpath) {
+		error = -ENOMEM;
+		goto out;
+	}
+	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
+	if (!devpath_string) {
+		error = -ENOMEM;
+		goto out;
+	}
+	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
+	envp[0] = devpath_string;
+	envp[1] = NULL;
+
+	name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
+	if (!name) {
+		error = -ENOMEM;
+		goto out;
+	}
+
+	error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
+	if (error)
+		goto out;
+
+	/* Install the new kobject name */
+	dup_name = kobj->name;
+	kobj->name = name;
+
+	/* This function is mostly/only used for network interface.
+	 * Some hotplug package track interfaces by their name and
+	 * therefore want to know when the name is changed by the user. */
+	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+
+out:
+	kfree_const(dup_name);
+	kfree(devpath_string);
+	kfree(devpath);
+	kobject_put(kobj);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(kobject_rename);
+
+/**
+ * kobject_move() - Move object to another parent.
+ * @kobj: object in question.
+ * @new_parent: object's new parent (can be NULL)
+ */
+int kobject_move(struct kobject *kobj, struct kobject *new_parent)
+{
+	int error;
+	struct kobject *old_parent;
+	const char *devpath = NULL;
+	char *devpath_string = NULL;
+	char *envp[2];
+
+	kobj = kobject_get(kobj);
+	if (!kobj)
+		return -EINVAL;
+	new_parent = kobject_get(new_parent);
+	if (!new_parent) {
+		if (kobj->kset)
+			new_parent = kobject_get(&kobj->kset->kobj);
+	}
+
+	/* old object path */
+	devpath = kobject_get_path(kobj, GFP_KERNEL);
+	if (!devpath) {
+		error = -ENOMEM;
+		goto out;
+	}
+	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
+	if (!devpath_string) {
+		error = -ENOMEM;
+		goto out;
+	}
+	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
+	envp[0] = devpath_string;
+	envp[1] = NULL;
+	error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
+	if (error)
+		goto out;
+	old_parent = kobj->parent;
+	kobj->parent = new_parent;
+	new_parent = NULL;
+	kobject_put(old_parent);
+	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+out:
+	kobject_put(new_parent);
+	kobject_put(kobj);
+	kfree(devpath_string);
+	kfree(devpath);
+	return error;
+}
+EXPORT_SYMBOL_GPL(kobject_move);
+
+static void __kobject_del(struct kobject *kobj)
+{
+	struct kernfs_node *sd;
+	const struct kobj_type *ktype;
+
+	sd = kobj->sd;
+	ktype = get_ktype(kobj);
+
+	if (ktype)
+		sysfs_remove_groups(kobj, ktype->default_groups);
+
+	/* send "remove" if the caller did not do it but sent "add" */
+	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
+		pr_debug("'%s' (%p): auto cleanup 'remove' event\n",
+			 kobject_name(kobj), kobj);
+		kobject_uevent(kobj, KOBJ_REMOVE);
+	}
+
+	sysfs_remove_dir(kobj);
+	sysfs_put(sd);
+
+	kobj->state_in_sysfs = 0;
+	kobj_kset_leave(kobj);
+	kobj->parent = NULL;
+}
+
+/**
+ * kobject_del() - Unlink kobject from hierarchy.
+ * @kobj: object.
+ *
+ * This is the function that should be called to delete an object
+ * successfully added via kobject_add().
+ */
+void kobject_del(struct kobject *kobj)
+{
+	struct kobject *parent;
+
+	if (!kobj)
+		return;
+
+	parent = kobj->parent;
+	__kobject_del(kobj);
+	kobject_put(parent);
+}
+EXPORT_SYMBOL(kobject_del);
+
+/**
+ * kobject_get() - Increment refcount for object.
+ * @kobj: object.
+ */
+struct kobject *kobject_get(struct kobject *kobj)
+{
+	if (kobj) {
+		if (!kobj->state_initialized)
+			WARN(1, KERN_WARNING
+				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
+			     kobject_name(kobj), kobj);
+		kref_get(&kobj->kref);
+	}
+	return kobj;
+}
+EXPORT_SYMBOL(kobject_get);
+
+struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
+{
+	if (!kobj)
+		return NULL;
+	if (!kref_get_unless_zero(&kobj->kref))
+		kobj = NULL;
+	return kobj;
+}
+EXPORT_SYMBOL(kobject_get_unless_zero);
+
+/*
+ * kobject_cleanup - free kobject resources.
+ * @kobj: object to cleanup
+ */
+static void kobject_cleanup(struct kobject *kobj)
+{
+	struct kobject *parent = kobj->parent;
+	const struct kobj_type *t = get_ktype(kobj);
+	const char *name = kobj->name;
+
+	pr_debug("'%s' (%p): %s, parent %p\n",
+		 kobject_name(kobj), kobj, __func__, kobj->parent);
+
+	if (t && !t->release)
+		pr_debug("'%s' (%p): does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
+			 kobject_name(kobj), kobj);
+
+	/* remove from sysfs if the caller did not do it */
+	if (kobj->state_in_sysfs) {
+		pr_debug("'%s' (%p): auto cleanup kobject_del\n",
+			 kobject_name(kobj), kobj);
+		__kobject_del(kobj);
+	} else {
+		/* avoid dropping the parent reference unnecessarily */
+		parent = NULL;
+	}
+
+	if (t && t->release) {
+		pr_debug("'%s' (%p): calling ktype release\n",
+			 kobject_name(kobj), kobj);
+		t->release(kobj);
+	}
+
+	/* free name if we allocated it */
+	if (name) {
+		pr_debug("'%s': free name\n", name);
+		kfree_const(name);
+	}
+
+	kobject_put(parent);
+}
+
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+static void kobject_delayed_cleanup(struct work_struct *work)
+{
+	kobject_cleanup(container_of(to_delayed_work(work),
+				     struct kobject, release));
+}
+#endif
+
+static void kobject_release(struct kref *kref)
+{
+	struct kobject *kobj = container_of(kref, struct kobject, kref);
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+	unsigned long delay = HZ + HZ * get_random_u32_below(4);
+	pr_info("'%s' (%p): %s, parent %p (delayed %ld)\n",
+		kobject_name(kobj), kobj, __func__, kobj->parent, delay);
+	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
+
+	schedule_delayed_work(&kobj->release, delay);
+#else
+	kobject_cleanup(kobj);
+#endif
+}
+
+/**
+ * kobject_put() - Decrement refcount for object.
+ * @kobj: object.
+ *
+ * Decrement the refcount, and if 0, call kobject_cleanup().
+ */
+void kobject_put(struct kobject *kobj)
+{
+	if (kobj) {
+		if (!kobj->state_initialized)
+			WARN(1, KERN_WARNING
+				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
+			     kobject_name(kobj), kobj);
+		kref_put(&kobj->kref, kobject_release);
+	}
+}
+EXPORT_SYMBOL(kobject_put);
+
+static void dynamic_kobj_release(struct kobject *kobj)
+{
+	pr_debug("(%p): %s\n", kobj, __func__);
+	kfree(kobj);
+}
+
+static const struct kobj_type dynamic_kobj_ktype = {
+	.release	= dynamic_kobj_release,
+	.sysfs_ops	= &kobj_sysfs_ops,
+};
+
+/**
+ * kobject_create() - Create a struct kobject dynamically.
+ *
+ * This function creates a kobject structure dynamically and sets it up
+ * to be a "dynamic" kobject with a default release function set up.
+ *
+ * If the kobject was not able to be created, NULL will be returned.
+ * The kobject structure returned from here must be cleaned up with a
+ * call to kobject_put() and not kfree(), as kobject_init() has
+ * already been called on this structure.
+ */
+static struct kobject *kobject_create(void)
+{
+	struct kobject *kobj;
+
+	kobj = kzalloc_obj(*kobj);
+	if (!kobj)
+		return NULL;
+
+	kobject_init(kobj, &dynamic_kobj_ktype);
+	return kobj;
+}
+
+/**
+ * kobject_create_and_add() - Create a struct kobject dynamically and
+ *                            register it with sysfs.
+ * @name: the name for the kobject
+ * @parent: the parent kobject of this kobject, if any.
+ *
+ * This function creates a kobject structure dynamically and registers it
+ * with sysfs.  When you are finished with this structure, call
+ * kobject_put() and the structure will be dynamically freed when
+ * it is no longer being used.
+ *
+ * If the kobject was not able to be created, NULL will be returned.
+ */
+struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
+{
+	struct kobject *kobj;
+	int retval;
+
+	kobj = kobject_create();
+	if (!kobj)
+		return NULL;
+
+	retval = kobject_add(kobj, parent, "%s", name);
+	if (retval) {
+		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
+		kobject_put(kobj);
+		kobj = NULL;
+	}
+	return kobj;
+}
+EXPORT_SYMBOL_GPL(kobject_create_and_add);
+
+/**
+ * kset_init() - Initialize a kset for use.
+ * @k: kset
+ */
+void kset_init(struct kset *k)
+{
+	kobject_init_internal(&k->kobj);
+	INIT_LIST_HEAD(&k->list);
+	spin_lock_init(&k->list_lock);
+}
+
+/* default kobject attribute operations */
+static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
+			      char *buf)
+{
+	struct kobj_attribute *kattr;
+	ssize_t ret = -EIO;
+
+	kattr = container_of_const(attr, struct kobj_attribute, attr);
+	if (kattr->show)
+		ret = kattr->show(kobj, kattr, buf);
+	else if (kattr->show_const)
+		ret = kattr->show_const(kobj, kattr, buf);
+	return ret;
+}
+
+static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct kobj_attribute *kattr;
+	ssize_t ret = -EIO;
+
+	kattr = container_of_const(attr, struct kobj_attribute, attr);
+	if (kattr->store)
+		ret = kattr->store(kobj, kattr, buf, count);
+	else if (kattr->store_const)
+		ret = kattr->store_const(kobj, kattr, buf, count);
+	return ret;
+}
+
+const struct sysfs_ops kobj_sysfs_ops = {
+	.show	= kobj_attr_show,
+	.store	= kobj_attr_store,
+};
+EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
+
+/**
+ * kset_register() - Initialize and add a kset.
+ * @k: kset.
+ *
+ * NOTE: On error, the kset.kobj.name allocated by() kobj_set_name()
+ * is freed, it can not be used any more.
+ */
+int kset_register(struct kset *k)
+{
+	int err;
+
+	if (!k)
+		return -EINVAL;
+
+	if (!k->kobj.ktype) {
+		pr_err("must have a ktype to be initialized properly!\n");
+		return -EINVAL;
+	}
+
+	kset_init(k);
+	err = kobject_add_internal(&k->kobj);
+	if (err) {
+		kfree_const(k->kobj.name);
+		/* Set it to NULL to avoid accessing bad pointer in callers. */
+		k->kobj.name = NULL;
+		return err;
+	}
+	kobject_uevent(&k->kobj, KOBJ_ADD);
+	return 0;
+}
+EXPORT_SYMBOL(kset_register);
+
+/**
+ * kset_unregister() - Remove a kset.
+ * @k: kset.
+ */
+void kset_unregister(struct kset *k)
+{
+	if (!k)
+		return;
+	kobject_del(&k->kobj);
+	kobject_put(&k->kobj);
+}
+EXPORT_SYMBOL(kset_unregister);
+
+/**
+ * kset_find_obj() - Search for object in kset.
+ * @kset: kset we're looking in.
+ * @name: object's name.
+ *
+ * Lock kset via @kset->subsys, and iterate over @kset->list,
+ * looking for a matching kobject. If matching object is found
+ * take a reference and return the object.
+ */
+struct kobject *kset_find_obj(struct kset *kset, const char *name)
+{
+	struct kobject *k;
+	struct kobject *ret = NULL;
+
+	spin_lock(&kset->list_lock);
+
+	list_for_each_entry(k, &kset->list, entry) {
+		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
+			ret = kobject_get_unless_zero(k);
+			break;
+		}
+	}
+
+	spin_unlock(&kset->list_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kset_find_obj);
+
+static void kset_release(struct kobject *kobj)
+{
+	struct kset *kset = container_of(kobj, struct kset, kobj);
+	pr_debug("'%s' (%p): %s\n",
+		 kobject_name(kobj), kobj, __func__);
+	kfree(kset);
+}
+
+static void kset_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
+{
+	if (kobj->parent)
+		kobject_get_ownership(kobj->parent, uid, gid);
+}
+
+static const struct kobj_type kset_ktype = {
+	.sysfs_ops	= &kobj_sysfs_ops,
+	.release	= kset_release,
+	.get_ownership	= kset_get_ownership,
+};
+
+/**
+ * kset_create() - Create a struct kset dynamically.
+ *
+ * @name: the name for the kset
+ * @uevent_ops: a struct kset_uevent_ops for the kset
+ * @parent_kobj: the parent kobject of this kset, if any.
+ *
+ * This function creates a kset structure dynamically.  This structure can
+ * then be registered with the system and show up in sysfs with a call to
+ * kset_register().  When you are finished with this structure, if
+ * kset_register() has been called, call kset_unregister() and the
+ * structure will be dynamically freed when it is no longer being used.
+ *
+ * If the kset was not able to be created, NULL will be returned.
+ */
+static struct kset *kset_create(const char *name,
+				const struct kset_uevent_ops *uevent_ops,
+				struct kobject *parent_kobj)
+{
+	struct kset *kset;
+	int retval;
+
+	kset = kzalloc_obj(*kset);
+	if (!kset)
+		return NULL;
+	retval = kobject_set_name(&kset->kobj, "%s", name);
+	if (retval) {
+		kfree(kset);
+		return NULL;
+	}
+	kset->uevent_ops = uevent_ops;
+	kset->kobj.parent = parent_kobj;
+
+	/*
+	 * The kobject of this kset will have a type of kset_ktype and belong to
+	 * no kset itself.  That way we can properly free it when it is
+	 * finished being used.
+	 */
+	kset->kobj.ktype = &kset_ktype;
+	kset->kobj.kset = NULL;
+
+	return kset;
+}
+
+/**
+ * kset_create_and_add() - Create a struct kset dynamically and add it to sysfs.
+ *
+ * @name: the name for the kset
+ * @uevent_ops: a struct kset_uevent_ops for the kset
+ * @parent_kobj: the parent kobject of this kset, if any.
+ *
+ * This function creates a kset structure dynamically and registers it
+ * with sysfs.  When you are finished with this structure, call
+ * kset_unregister() and the structure will be dynamically freed when it
+ * is no longer being used.
+ *
+ * If the kset was not able to be created, NULL will be returned.
+ */
+struct kset *kset_create_and_add(const char *name,
+				 const struct kset_uevent_ops *uevent_ops,
+				 struct kobject *parent_kobj)
+{
+	struct kset *kset;
+	int error;
+
+	kset = kset_create(name, uevent_ops, parent_kobj);
+	if (!kset)
+		return NULL;
+	error = kset_register(kset);
+	if (error) {
+		kfree(kset);
+		return NULL;
+	}
+	return kset;
+}
+EXPORT_SYMBOL_GPL(kset_create_and_add);
+
+
+static DEFINE_SPINLOCK(kobj_ns_type_lock);
+static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
+
+int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
+{
+	enum kobj_ns_type type = ops->type;
+	int error;
+
+	spin_lock(&kobj_ns_type_lock);
+
+	error = -EINVAL;
+	if (!kobj_ns_type_is_valid(type))
+		goto out;
+
+	error = -EBUSY;
+	if (kobj_ns_ops_tbl[type])
+		goto out;
+
+	error = 0;
+	kobj_ns_ops_tbl[type] = ops;
+
+out:
+	spin_unlock(&kobj_ns_type_lock);
+	return error;
+}
+
+int kobj_ns_type_registered(enum kobj_ns_type type)
+{
+	int registered = 0;
+
+	spin_lock(&kobj_ns_type_lock);
+	if (kobj_ns_type_is_valid(type))
+		registered = kobj_ns_ops_tbl[type] != NULL;
+	spin_unlock(&kobj_ns_type_lock);
+
+	return registered;
+}
+
+const struct kobj_ns_type_operations *kobj_child_ns_ops(const struct kobject *parent)
+{
+	const struct kobj_ns_type_operations *ops = NULL;
+
+	if (parent && parent->ktype && parent->ktype->child_ns_type)
+		ops = parent->ktype->child_ns_type(parent);
+
+	return ops;
+}
+
+const struct kobj_ns_type_operations *kobj_ns_ops(const struct kobject *kobj)
+{
+	return kobj_child_ns_ops(kobj->parent);
+}
+
+bool kobj_ns_current_may_mount(enum kobj_ns_type type)
+{
+	bool may_mount = true;
+
+	spin_lock(&kobj_ns_type_lock);
+	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
+		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
+	spin_unlock(&kobj_ns_type_lock);
+
+	return may_mount;
+}
+
+struct ns_common *kobj_ns_grab_current(enum kobj_ns_type type)
+{
+	struct ns_common *ns = NULL;
+
+	spin_lock(&kobj_ns_type_lock);
+	if (kobj_ns_type_is_valid(type) && kobj_ns_ops_tbl[type])
+		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
+	spin_unlock(&kobj_ns_type_lock);
+
+	return ns;
+}
+EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
+
+void kobj_ns_drop(enum kobj_ns_type type, struct ns_common *ns)
+{
+	spin_lock(&kobj_ns_type_lock);
+	if (kobj_ns_type_is_valid(type) &&
+	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
+		kobj_ns_ops_tbl[type]->drop_ns(ns);
+	spin_unlock(&kobj_ns_type_lock);
+}
+EXPORT_SYMBOL_GPL(kobj_ns_drop);