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, 634 insertions, 0 deletions

diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
new file mode 100644
index 000000000..d7f3a8912
--- /dev/null
+++ b/drivers/acpi/dock.c
@@ -0,0 +1,634 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  dock.c - ACPI dock station driver
+ *
+ *  Copyright (C) 2006, 2014, Intel Corp.
+ *  Author: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
+ *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/jiffies.h>
+#include <linux/stddef.h>
+#include <linux/acpi.h>
+
+#include "internal.h"
+
+static bool immediate_undock = 1;
+module_param(immediate_undock, bool, 0644);
+MODULE_PARM_DESC(immediate_undock, "1 (default) will cause the driver to "
+	"undock immediately when the undock button is pressed, 0 will cause"
+	" the driver to wait for userspace to write the undock sysfs file "
+	" before undocking");
+
+struct dock_station {
+	acpi_handle handle;
+	unsigned long last_dock_time;
+	u32 flags;
+	struct list_head dependent_devices;
+
+	struct list_head sibling;
+	struct platform_device *dock_device;
+};
+static LIST_HEAD(dock_stations);
+static int dock_station_count;
+
+struct dock_dependent_device {
+	struct list_head list;
+	struct acpi_device *adev;
+};
+
+#define DOCK_DOCKING	0x00000001
+#define DOCK_UNDOCKING  0x00000002
+#define DOCK_IS_DOCK	0x00000010
+#define DOCK_IS_ATA	0x00000020
+#define DOCK_IS_BAT	0x00000040
+#define DOCK_EVENT	3
+#define UNDOCK_EVENT	2
+
+enum dock_callback_type {
+	DOCK_CALL_HANDLER,
+	DOCK_CALL_FIXUP,
+	DOCK_CALL_UEVENT,
+};
+
+/*****************************************************************************
+ *                         Dock Dependent device functions                   *
+ *****************************************************************************/
+/**
+ * add_dock_dependent_device - associate a device with the dock station
+ * @ds: Dock station.
+ * @adev: Dependent ACPI device object.
+ *
+ * Add the dependent device to the dock's dependent device list.
+ */
+static int add_dock_dependent_device(struct dock_station *ds,
+				     struct acpi_device *adev)
+{
+	struct dock_dependent_device *dd;
+
+	dd = kzalloc_obj(*dd);
+	if (!dd)
+		return -ENOMEM;
+
+	dd->adev = adev;
+	INIT_LIST_HEAD(&dd->list);
+	list_add_tail(&dd->list, &ds->dependent_devices);
+
+	return 0;
+}
+
+static void dock_hotplug_event(struct dock_dependent_device *dd, u32 event,
+			       enum dock_callback_type cb_type)
+{
+	struct acpi_device *adev = dd->adev;
+	acpi_hp_fixup fixup = NULL;
+	acpi_hp_uevent uevent = NULL;
+	acpi_hp_notify notify = NULL;
+
+	acpi_lock_hp_context();
+
+	if (adev->hp) {
+		if (cb_type == DOCK_CALL_FIXUP)
+			fixup = adev->hp->fixup;
+		else if (cb_type == DOCK_CALL_UEVENT)
+			uevent = adev->hp->uevent;
+		else
+			notify = adev->hp->notify;
+	}
+
+	acpi_unlock_hp_context();
+
+	if (fixup)
+		fixup(adev);
+	else if (uevent)
+		uevent(adev, event);
+	else if (notify)
+		notify(adev, event);
+}
+
+static struct dock_station *find_dock_station(acpi_handle handle)
+{
+	struct dock_station *ds;
+
+	list_for_each_entry(ds, &dock_stations, sibling)
+		if (ds->handle == handle)
+			return ds;
+
+	return NULL;
+}
+
+/**
+ * find_dock_dependent_device - get a device dependent on this dock
+ * @ds: the dock station
+ * @adev: ACPI device object to find.
+ *
+ * iterate over the dependent device list for this dock.  If the
+ * dependent device matches the handle, return.
+ */
+static struct dock_dependent_device *
+find_dock_dependent_device(struct dock_station *ds, struct acpi_device *adev)
+{
+	struct dock_dependent_device *dd;
+
+	list_for_each_entry(dd, &ds->dependent_devices, list)
+		if (adev == dd->adev)
+			return dd;
+
+	return NULL;
+}
+
+void register_dock_dependent_device(struct acpi_device *adev,
+				    acpi_handle dshandle)
+{
+	struct dock_station *ds = find_dock_station(dshandle);
+
+	if (ds && !find_dock_dependent_device(ds, adev))
+		add_dock_dependent_device(ds, adev);
+}
+
+/*****************************************************************************
+ *                         Dock functions                                    *
+ *****************************************************************************/
+
+/**
+ * is_dock_device - see if a device is on a dock station
+ * @adev: ACPI device object to check.
+ *
+ * If this device is either the dock station itself,
+ * or is a device dependent on the dock station, then it
+ * is a dock device
+ */
+int is_dock_device(struct acpi_device *adev)
+{
+	struct dock_station *dock_station;
+
+	if (!dock_station_count)
+		return 0;
+
+	if (acpi_dock_match(adev->handle))
+		return 1;
+
+	list_for_each_entry(dock_station, &dock_stations, sibling)
+		if (find_dock_dependent_device(dock_station, adev))
+			return 1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(is_dock_device);
+
+/**
+ * dock_present - see if the dock station is present.
+ * @ds: the dock station
+ *
+ * execute the _STA method.  note that present does not
+ * imply that we are docked.
+ */
+static int dock_present(struct dock_station *ds)
+{
+	unsigned long long sta;
+	acpi_status status;
+
+	if (ds) {
+		status = acpi_evaluate_integer(ds->handle, "_STA", NULL, &sta);
+		if (ACPI_SUCCESS(status) && sta)
+			return 1;
+	}
+	return 0;
+}
+
+/**
+ * hot_remove_dock_devices - Remove dock station devices.
+ * @ds: Dock station.
+ */
+static void hot_remove_dock_devices(struct dock_station *ds)
+{
+	struct dock_dependent_device *dd;
+
+	/*
+	 * Walk the list in reverse order so that devices that have been added
+	 * last are removed first (in case there are some indirect dependencies
+	 * between them).
+	 */
+	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
+		dock_hotplug_event(dd, ACPI_NOTIFY_EJECT_REQUEST,
+				   DOCK_CALL_HANDLER);
+
+	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
+		acpi_bus_trim(dd->adev);
+}
+
+/**
+ * hotplug_dock_devices - Insert devices on a dock station.
+ * @ds: the dock station
+ * @event: either bus check or device check request
+ *
+ * Some devices on the dock station need to have drivers called
+ * to perform hotplug operations after a dock event has occurred.
+ * Traverse the list of dock devices that have registered a
+ * hotplug handler, and call the handler.
+ */
+static void hotplug_dock_devices(struct dock_station *ds, u32 event)
+{
+	struct dock_dependent_device *dd;
+
+	/* Call driver specific post-dock fixups. */
+	list_for_each_entry(dd, &ds->dependent_devices, list)
+		dock_hotplug_event(dd, event, DOCK_CALL_FIXUP);
+
+	/* Call driver specific hotplug functions. */
+	list_for_each_entry(dd, &ds->dependent_devices, list)
+		dock_hotplug_event(dd, event, DOCK_CALL_HANDLER);
+
+	/*
+	 * Check if all devices have been enumerated already.  If not, run
+	 * acpi_bus_scan() for them and that will cause scan handlers to be
+	 * attached to device objects or acpi_drivers to be stopped/started if
+	 * they are present.
+	 */
+	list_for_each_entry(dd, &ds->dependent_devices, list) {
+		struct acpi_device *adev = dd->adev;
+
+		if (!acpi_device_enumerated(adev)) {
+			int ret = acpi_bus_scan(adev->handle);
+
+			if (ret)
+				dev_dbg(&adev->dev, "scan error %d\n", -ret);
+		}
+	}
+}
+
+static void dock_event(struct dock_station *ds, u32 event, int num)
+{
+	struct device *dev = &ds->dock_device->dev;
+	char event_string[13];
+	char *envp[] = { event_string, NULL };
+	struct dock_dependent_device *dd;
+
+	if (num == UNDOCK_EVENT)
+		sprintf(event_string, "EVENT=undock");
+	else
+		sprintf(event_string, "EVENT=dock");
+
+	/*
+	 * Indicate that the status of the dock station has
+	 * changed.
+	 */
+	if (num == DOCK_EVENT)
+		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
+
+	list_for_each_entry(dd, &ds->dependent_devices, list)
+		dock_hotplug_event(dd, event, DOCK_CALL_UEVENT);
+
+	if (num != DOCK_EVENT)
+		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
+}
+
+/**
+ * handle_dock - handle a dock event
+ * @ds: the dock station
+ * @dock: to dock, or undock - that is the question
+ *
+ * Execute the _DCK method in response to an acpi event
+ */
+static void handle_dock(struct dock_station *ds, int dock)
+{
+	acpi_status status;
+	struct acpi_object_list arg_list;
+	union acpi_object arg;
+	unsigned long long value;
+
+	acpi_handle_info(ds->handle, "%s\n", dock ? "docking" : "undocking");
+
+	/* _DCK method has one argument */
+	arg_list.count = 1;
+	arg_list.pointer = &arg;
+	arg.type = ACPI_TYPE_INTEGER;
+	arg.integer.value = dock;
+	status = acpi_evaluate_integer(ds->handle, "_DCK", &arg_list, &value);
+	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
+		acpi_handle_err(ds->handle, "Failed to execute _DCK (0x%x)\n",
+				status);
+}
+
+static inline void dock(struct dock_station *ds)
+{
+	handle_dock(ds, 1);
+}
+
+static inline void undock(struct dock_station *ds)
+{
+	handle_dock(ds, 0);
+}
+
+static inline void begin_dock(struct dock_station *ds)
+{
+	ds->flags |= DOCK_DOCKING;
+}
+
+static inline void complete_dock(struct dock_station *ds)
+{
+	ds->flags &= ~(DOCK_DOCKING);
+	ds->last_dock_time = jiffies;
+}
+
+static inline void begin_undock(struct dock_station *ds)
+{
+	ds->flags |= DOCK_UNDOCKING;
+}
+
+static inline void complete_undock(struct dock_station *ds)
+{
+	ds->flags &= ~(DOCK_UNDOCKING);
+}
+
+/**
+ * dock_in_progress - see if we are in the middle of handling a dock event
+ * @ds: the dock station
+ *
+ * Sometimes while docking, false dock events can be sent to the driver
+ * because good connections aren't made or some other reason.  Ignore these
+ * if we are in the middle of doing something.
+ */
+static int dock_in_progress(struct dock_station *ds)
+{
+	if ((ds->flags & DOCK_DOCKING) ||
+	    time_before(jiffies, (ds->last_dock_time + HZ)))
+		return 1;
+	return 0;
+}
+
+/**
+ * handle_eject_request - handle an undock request checking for error conditions
+ * @ds: The dock station to undock.
+ * @event: The ACPI event number associated with the undock request.
+ *
+ * Check to make sure the dock device is still present, then undock and
+ * hotremove all the devices that may need removing.
+ */
+static int handle_eject_request(struct dock_station *ds, u32 event)
+{
+	if (dock_in_progress(ds))
+		return -EBUSY;
+
+	/*
+	 * here we need to generate the undock
+	 * event prior to actually doing the undock
+	 * so that the device struct still exists.
+	 * Also, even send the dock event if the
+	 * device is not present anymore
+	 */
+	dock_event(ds, event, UNDOCK_EVENT);
+
+	hot_remove_dock_devices(ds);
+	undock(ds);
+	acpi_evaluate_lck(ds->handle, 0);
+	acpi_evaluate_ej0(ds->handle);
+	if (dock_present(ds)) {
+		acpi_handle_err(ds->handle, "Unable to undock!\n");
+		return -EBUSY;
+	}
+	complete_undock(ds);
+	return 0;
+}
+
+/**
+ * dock_notify - Handle ACPI dock notification.
+ * @adev: Dock station's ACPI device object.
+ * @event: Event code.
+ *
+ * If we are notified to dock, then check to see if the dock is
+ * present and then dock.  Notify all drivers of the dock event,
+ * and then hotplug and devices that may need hotplugging.
+ */
+int dock_notify(struct acpi_device *adev, u32 event)
+{
+	acpi_handle handle = adev->handle;
+	struct dock_station *ds = find_dock_station(handle);
+	int surprise_removal = 0;
+
+	if (!ds)
+		return -ENODEV;
+
+	/*
+	 * According to acpi spec 3.0a, if a DEVICE_CHECK notification
+	 * is sent and _DCK is present, it is assumed to mean an undock
+	 * request.
+	 */
+	if ((ds->flags & DOCK_IS_DOCK) && event == ACPI_NOTIFY_DEVICE_CHECK)
+		event = ACPI_NOTIFY_EJECT_REQUEST;
+
+	/*
+	 * dock station: BUS_CHECK - docked or surprise removal
+	 *		 DEVICE_CHECK - undocked
+	 * other device: BUS_CHECK/DEVICE_CHECK - added or surprise removal
+	 *
+	 * To simplify event handling, dock dependent device handler always
+	 * get ACPI_NOTIFY_BUS_CHECK/ACPI_NOTIFY_DEVICE_CHECK for add and
+	 * ACPI_NOTIFY_EJECT_REQUEST for removal
+	 */
+	switch (event) {
+	case ACPI_NOTIFY_BUS_CHECK:
+	case ACPI_NOTIFY_DEVICE_CHECK:
+		if (!dock_in_progress(ds) && !acpi_device_enumerated(adev)) {
+			begin_dock(ds);
+			dock(ds);
+			if (!dock_present(ds)) {
+				acpi_handle_err(handle, "Unable to dock!\n");
+				complete_dock(ds);
+				break;
+			}
+			hotplug_dock_devices(ds, event);
+			complete_dock(ds);
+			dock_event(ds, event, DOCK_EVENT);
+			acpi_evaluate_lck(ds->handle, 1);
+			acpi_update_all_gpes();
+			break;
+		}
+		if (dock_present(ds) || dock_in_progress(ds))
+			break;
+		/* This is a surprise removal */
+		surprise_removal = 1;
+		event = ACPI_NOTIFY_EJECT_REQUEST;
+		/* Fall back */
+		fallthrough;
+	case ACPI_NOTIFY_EJECT_REQUEST:
+		begin_undock(ds);
+		if ((immediate_undock && !(ds->flags & DOCK_IS_ATA))
+		   || surprise_removal)
+			handle_eject_request(ds, event);
+		else
+			dock_event(ds, event, UNDOCK_EVENT);
+		break;
+	}
+	return 0;
+}
+
+/*
+ * show_docked - read method for "docked" file in sysfs
+ */
+static ssize_t docked_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct dock_station *dock_station = dev->platform_data;
+	struct acpi_device *adev = acpi_fetch_acpi_dev(dock_station->handle);
+
+	return sysfs_emit(buf, "%u\n", acpi_device_enumerated(adev));
+}
+static DEVICE_ATTR_RO(docked);
+
+/*
+ * show_flags - read method for flags file in sysfs
+ */
+static ssize_t flags_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct dock_station *dock_station = dev->platform_data;
+
+	return sysfs_emit(buf, "%d\n", dock_station->flags);
+
+}
+static DEVICE_ATTR_RO(flags);
+
+/*
+ * write_undock - write method for "undock" file in sysfs
+ */
+static ssize_t undock_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	int ret;
+	struct dock_station *dock_station = dev->platform_data;
+
+	if (!count)
+		return -EINVAL;
+
+	acpi_scan_lock_acquire();
+	begin_undock(dock_station);
+	ret = handle_eject_request(dock_station, ACPI_NOTIFY_EJECT_REQUEST);
+	acpi_scan_lock_release();
+	return ret ? ret : count;
+}
+static DEVICE_ATTR_WO(undock);
+
+/*
+ * show_dock_uid - read method for "uid" file in sysfs
+ */
+static ssize_t uid_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	unsigned long long lbuf;
+	struct dock_station *dock_station = dev->platform_data;
+
+	acpi_status status = acpi_evaluate_integer(dock_station->handle,
+					"_UID", NULL, &lbuf);
+	if (ACPI_FAILURE(status))
+		return 0;
+
+	return sysfs_emit(buf, "%llx\n", lbuf);
+}
+static DEVICE_ATTR_RO(uid);
+
+static ssize_t type_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct dock_station *dock_station = dev->platform_data;
+	char *type;
+
+	if (dock_station->flags & DOCK_IS_DOCK)
+		type = "dock_station";
+	else if (dock_station->flags & DOCK_IS_ATA)
+		type = "ata_bay";
+	else if (dock_station->flags & DOCK_IS_BAT)
+		type = "battery_bay";
+	else
+		type = "unknown";
+
+	return sysfs_emit(buf, "%s\n", type);
+}
+static DEVICE_ATTR_RO(type);
+
+static struct attribute *dock_attributes[] = {
+	&dev_attr_docked.attr,
+	&dev_attr_flags.attr,
+	&dev_attr_undock.attr,
+	&dev_attr_uid.attr,
+	&dev_attr_type.attr,
+	NULL
+};
+
+static const struct attribute_group dock_attribute_group = {
+	.attrs = dock_attributes
+};
+
+/**
+ * acpi_dock_add - Add a new dock station
+ * @adev: Dock station ACPI device object.
+ *
+ * allocated and initialize a new dock station device.
+ */
+void acpi_dock_add(struct acpi_device *adev)
+{
+	struct dock_station *dock_station, ds = { NULL, };
+	struct platform_device_info pdevinfo;
+	acpi_handle handle = adev->handle;
+	struct platform_device *dd;
+	int ret;
+
+	memset(&pdevinfo, 0, sizeof(pdevinfo));
+	pdevinfo.name = "dock";
+	pdevinfo.id = dock_station_count;
+	pdevinfo.fwnode = acpi_fwnode_handle(adev);
+	pdevinfo.data = &ds;
+	pdevinfo.size_data = sizeof(ds);
+	dd = platform_device_register_full(&pdevinfo);
+	if (IS_ERR(dd))
+		return;
+
+	dock_station = dd->dev.platform_data;
+
+	dock_station->handle = handle;
+	dock_station->dock_device = dd;
+	dock_station->last_dock_time = jiffies - HZ;
+
+	INIT_LIST_HEAD(&dock_station->sibling);
+	INIT_LIST_HEAD(&dock_station->dependent_devices);
+
+	/* we want the dock device to send uevents */
+	dev_set_uevent_suppress(&dd->dev, 0);
+
+	if (acpi_dock_match(handle))
+		dock_station->flags |= DOCK_IS_DOCK;
+	if (acpi_ata_match(handle))
+		dock_station->flags |= DOCK_IS_ATA;
+	if (acpi_device_is_battery(adev))
+		dock_station->flags |= DOCK_IS_BAT;
+
+	ret = sysfs_create_group(&dd->dev.kobj, &dock_attribute_group);
+	if (ret)
+		goto err_unregister;
+
+	/* add the dock station as a device dependent on itself */
+	ret = add_dock_dependent_device(dock_station, adev);
+	if (ret)
+		goto err_rmgroup;
+
+	dock_station_count++;
+	list_add(&dock_station->sibling, &dock_stations);
+	adev->flags.is_dock_station = true;
+	dev_info(&adev->dev, "ACPI dock station (docks/bays count: %d)\n",
+		 dock_station_count);
+	return;
+
+err_rmgroup:
+	sysfs_remove_group(&dd->dev.kobj, &dock_attribute_group);
+
+err_unregister:
+	platform_device_unregister(dd);
+	acpi_handle_err(handle, "%s encountered error %d\n", __func__, ret);
+}