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, 354 insertions, 0 deletions

diff --git a/drivers/hid/hid-letsketch.c b/drivers/hid/hid-letsketch.c
new file mode 100644
index 000000000..b52e93a91
--- /dev/null
+++ b/drivers/hid/hid-letsketch.c
@@ -0,0 +1,354 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Driver for the LetSketch / VSON WP9620N drawing tablet.
+ * This drawing tablet is also sold under other brand names such as Case U,
+ * presumably this driver will work for all of them. But it has only been
+ * tested with a LetSketch WP9620N model.
+ *
+ * These tablets also work without a special HID driver, but then only part
+ * of the active area works and both the pad and stylus buttons are hardwired
+ * to special key-combos. E.g. the 2 stylus buttons send right mouse clicks /
+ * resp. "e" key presses.
+ *
+ * This device has 4 USB interfaces:
+ *
+ * Interface 0 EP 0x81 bootclass mouse, rdesc len 18, report id 0x08,
+ *                                                    Application(ff00.0001)
+ *  This interface sends raw event input reports in a custom format, but only
+ *  after doing the special dance from letsketch_probe(). After enabling this
+ *  interface the other 3 interfaces are disabled.
+ *
+ * Interface 1 EP 0x82 bootclass mouse, rdesc len 83, report id 0x0a, Tablet
+ *  This interface sends absolute events for the pen, including pressure,
+ *  but only for some part of the active area due to special "aspect ratio"
+ *  correction and only half by default since it assumes it will be used
+ *  with a phone in portraid mode, while using the tablet in landscape mode.
+ *  Also stylus + pad button events are not reported here.
+ *
+ * Interface 2 EP 0x83 bootclass keybd, rdesc len 64, report id none, Std Kbd
+ *  This interfaces send various hard-coded key-combos for the pad buttons
+ *  and "e" keypresses for the 2nd stylus button
+ *
+ * Interface 3 EP 0x84 bootclass mouse, rdesc len 75, report id 0x01, Std Mouse
+ *  This reports right-click mouse-button events for the 1st stylus button
+ */
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/usb.h>
+
+#include <linux/unaligned.h>
+
+#include "hid-ids.h"
+
+#define LETSKETCH_RAW_IF		0
+
+#define LETSKETCH_RAW_DATA_LEN		12
+#define LETSKETCH_RAW_REPORT_ID		8
+
+#define LETSKETCH_PAD_BUTTONS		5
+
+#define LETSKETCH_INFO_STR_IDX_BEGIN	0xc8
+#define LETSKETCH_INFO_STR_IDX_END	0xca
+
+#define LETSKETCH_GET_STRING_RETRIES	5
+
+struct letsketch_data {
+	struct hid_device *hdev;
+	struct input_dev *input_tablet;
+	struct input_dev *input_tablet_pad;
+	struct timer_list inrange_timer;
+};
+
+static int letsketch_open(struct input_dev *dev)
+{
+	struct letsketch_data *data = input_get_drvdata(dev);
+
+	return hid_hw_open(data->hdev);
+}
+
+static void letsketch_close(struct input_dev *dev)
+{
+	struct letsketch_data *data = input_get_drvdata(dev);
+
+	hid_hw_close(data->hdev);
+}
+
+static struct input_dev *letsketch_alloc_input_dev(struct letsketch_data *data)
+{
+	struct input_dev *input;
+
+	input = devm_input_allocate_device(&data->hdev->dev);
+	if (!input)
+		return NULL;
+
+	input->id.bustype = data->hdev->bus;
+	input->id.vendor  = data->hdev->vendor;
+	input->id.product = data->hdev->product;
+	input->id.version = data->hdev->bus;
+	input->phys = data->hdev->phys;
+	input->uniq = data->hdev->uniq;
+	input->open = letsketch_open;
+	input->close = letsketch_close;
+
+	input_set_drvdata(input, data);
+
+	return input;
+}
+
+static int letsketch_setup_input_tablet(struct letsketch_data *data)
+{
+	struct input_dev *input;
+
+	input = letsketch_alloc_input_dev(data);
+	if (!input)
+		return -ENOMEM;
+
+	input_set_abs_params(input, ABS_X, 0, 50800, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, 31750, 0, 0);
+	input_set_abs_params(input, ABS_PRESSURE, 0, 8192, 0, 0);
+	input_abs_set_res(input, ABS_X, 240);
+	input_abs_set_res(input, ABS_Y, 225);
+	input_set_capability(input, EV_KEY, BTN_TOUCH);
+	input_set_capability(input, EV_KEY, BTN_TOOL_PEN);
+	input_set_capability(input, EV_KEY, BTN_STYLUS);
+	input_set_capability(input, EV_KEY, BTN_STYLUS2);
+
+	/* All known brands selling this tablet use WP9620[N] as model name */
+	input->name = "WP9620 Tablet";
+
+	data->input_tablet = input;
+
+	return input_register_device(data->input_tablet);
+}
+
+static int letsketch_setup_input_tablet_pad(struct letsketch_data *data)
+{
+	struct input_dev *input;
+	int i;
+
+	input = letsketch_alloc_input_dev(data);
+	if (!input)
+		return -ENOMEM;
+
+	for (i = 0; i < LETSKETCH_PAD_BUTTONS; i++)
+		input_set_capability(input, EV_KEY, BTN_0 + i);
+
+	/*
+	 * These are never send on the pad input_dev, but must be set
+	 * on the Pad to make udev / libwacom happy.
+	 */
+	input_set_abs_params(input, ABS_X, 0, 1, 0, 0);
+	input_set_abs_params(input, ABS_Y, 0, 1, 0, 0);
+	input_set_capability(input, EV_KEY, BTN_STYLUS);
+
+	input->name = "WP9620 Pad";
+
+	data->input_tablet_pad = input;
+
+	return input_register_device(data->input_tablet_pad);
+}
+
+static void letsketch_inrange_timeout(struct timer_list *t)
+{
+	struct letsketch_data *data = timer_container_of(data, t,
+							 inrange_timer);
+	struct input_dev *input = data->input_tablet;
+
+	input_report_key(input, BTN_TOOL_PEN, 0);
+	input_sync(input);
+}
+
+static int letsketch_raw_event(struct hid_device *hdev,
+			       struct hid_report *report,
+			       u8 *raw_data, int size)
+{
+	struct letsketch_data *data = hid_get_drvdata(hdev);
+	struct input_dev *input;
+	int i;
+
+	if (size != LETSKETCH_RAW_DATA_LEN || raw_data[0] != LETSKETCH_RAW_REPORT_ID)
+		return 0;
+
+	switch (raw_data[1] & 0xf0) {
+	case 0x80: /* Pen data */
+		input = data->input_tablet;
+		input_report_key(input, BTN_TOOL_PEN, 1);
+		input_report_key(input, BTN_TOUCH, raw_data[1] & 0x01);
+		input_report_key(input, BTN_STYLUS, raw_data[1] & 0x02);
+		input_report_key(input, BTN_STYLUS2, raw_data[1] & 0x04);
+		input_report_abs(input, ABS_X,
+				 get_unaligned_le16(raw_data + 2));
+		input_report_abs(input, ABS_Y,
+				 get_unaligned_le16(raw_data + 4));
+		input_report_abs(input, ABS_PRESSURE,
+				 get_unaligned_le16(raw_data + 6));
+		/*
+		 * There is no out of range event, so use a timer for this
+		 * when in range we get an event approx. every 8 ms.
+		 */
+		mod_timer(&data->inrange_timer, jiffies + msecs_to_jiffies(100));
+		break;
+	case 0xe0: /* Pad data */
+		input = data->input_tablet_pad;
+		for (i = 0; i < LETSKETCH_PAD_BUTTONS; i++)
+			input_report_key(input, BTN_0 + i, raw_data[4] == (i + 1));
+		break;
+	default:
+		hid_warn(data->hdev, "Warning unknown data header: 0x%02x\n",
+			 raw_data[0]);
+		return 0;
+	}
+
+	input_sync(input);
+	return 0;
+}
+
+/*
+ * The tablets magic handshake to put it in raw mode relies on getting
+ * string descriptors. But the firmware is buggy and does not like it if
+ * we do this too fast. Even if we go slow sometimes the usb_string() call
+ * fails. Ignore errors and retry it a couple of times if necessary.
+ */
+static int letsketch_get_string(struct usb_device *udev, int index, char *buf, int size)
+{
+	int i, ret;
+
+	for (i = 0; i < LETSKETCH_GET_STRING_RETRIES; i++) {
+		usleep_range(5000, 7000);
+		ret = usb_string(udev, index, buf, size);
+		if (ret > 0)
+			return 0;
+	}
+
+	dev_err(&udev->dev, "Max retries (%d) exceeded reading string descriptor %d\n",
+		LETSKETCH_GET_STRING_RETRIES, index);
+	return ret ? ret : -EIO;
+}
+
+static int letsketch_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct device *dev = &hdev->dev;
+	struct letsketch_data *data;
+	struct usb_interface *intf;
+	struct usb_device *udev;
+	char buf[256];
+	int i, ret;
+
+	if (!hid_is_usb(hdev))
+		return -ENODEV;
+
+	intf = to_usb_interface(hdev->dev.parent);
+	if (intf->altsetting->desc.bInterfaceNumber != LETSKETCH_RAW_IF)
+		return -ENODEV; /* Ignore the other interfaces */
+
+	udev = interface_to_usbdev(intf);
+
+	/*
+	 * Instead of using a set-feature request, or even a custom USB ctrl
+	 * message the tablet needs this elaborate magic reading of USB
+	 * string descriptors to kick it into raw mode. This is what the
+	 * Windows drivers are seen doing in an USB trace under Windows.
+	 */
+	for (i = LETSKETCH_INFO_STR_IDX_BEGIN; i <= LETSKETCH_INFO_STR_IDX_END; i++) {
+		ret = letsketch_get_string(udev, i, buf, sizeof(buf));
+		if (ret)
+			return ret;
+
+		hid_info(hdev, "Device info: %s\n", buf);
+	}
+
+	for (i = 1; i <= 250; i++) {
+		ret = letsketch_get_string(udev, i, buf, sizeof(buf));
+		if (ret)
+			return ret;
+	}
+
+	ret = letsketch_get_string(udev, 0x64, buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	ret = letsketch_get_string(udev, LETSKETCH_INFO_STR_IDX_BEGIN, buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	/*
+	 * The tablet should be in raw mode now, end with a final delay before
+	 * doing further IO to the device.
+	 */
+	usleep_range(5000, 7000);
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->hdev = hdev;
+	timer_setup(&data->inrange_timer, letsketch_inrange_timeout, 0);
+	hid_set_drvdata(hdev, data);
+
+	ret = letsketch_setup_input_tablet(data);
+	if (ret)
+		goto err_shutdown_timer;
+
+	ret = letsketch_setup_input_tablet_pad(data);
+	if (ret)
+		goto err_shutdown_timer;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret)
+		goto err_shutdown_timer;
+
+	return 0;
+
+err_shutdown_timer:
+	/*
+	 * Drain any pending callback and permanently disable the timer
+	 * before devm releases data: if hid_hw_start() enabled I/O on an
+	 * always-poll-quirk device and then failed, raw_event may have
+	 * armed the timer already.
+	 */
+	timer_shutdown_sync(&data->inrange_timer);
+	return ret;
+}
+
+static void letsketch_remove(struct hid_device *hdev)
+{
+	struct letsketch_data *data = hid_get_drvdata(hdev);
+
+	/*
+	 * hid_hw_stop() synchronously kills the URBs that deliver
+	 * raw_event(), so once it returns no path can re-arm
+	 * inrange_timer.  timer_shutdown_sync() then drains any
+	 * in-flight callback and permanently disables further
+	 * mod_timer() calls before devm releases data.
+	 */
+	hid_hw_stop(hdev);
+	timer_shutdown_sync(&data->inrange_timer);
+}
+
+static const struct hid_device_id letsketch_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LETSKETCH, USB_DEVICE_ID_WP9620N) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, letsketch_devices);
+
+static struct hid_driver letsketch_driver = {
+	.name = "letsketch",
+	.id_table = letsketch_devices,
+	.probe = letsketch_probe,
+	.remove = letsketch_remove,
+	.raw_event = letsketch_raw_event,
+};
+module_hid_driver(letsketch_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("Driver for the LetSketch / VSON WP9620N drawing tablet");
+MODULE_LICENSE("GPL");