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, 200 insertions, 0 deletions

diff --git a/drivers/video/backlight/bd6107.c b/drivers/video/backlight/bd6107.c
new file mode 100644
index 000000000..6778b4030
--- /dev/null
+++ b/drivers/video/backlight/bd6107.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ROHM Semiconductor BD6107 LED Driver
+ *
+ * Copyright (C) 2013 Ideas on board SPRL
+ *
+ * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/platform_data/bd6107.h>
+#include <linux/slab.h>
+
+#define BD6107_PSCNT1				0x00
+#define BD6107_PSCNT1_PSCNTREG2			(1 << 2)
+#define BD6107_PSCNT1_PSCNTREG1			(1 << 0)
+#define BD6107_REGVSET				0x02
+#define BD6107_REGVSET_REG1VSET_2_85V		(1 << 2)
+#define BD6107_REGVSET_REG1VSET_2_80V		(0 << 2)
+#define BD6107_LEDCNT1				0x03
+#define BD6107_LEDCNT1_LEDONOFF2		(1 << 1)
+#define BD6107_LEDCNT1_LEDONOFF1		(1 << 0)
+#define BD6107_PORTSEL				0x04
+#define BD6107_PORTSEL_LEDM(n)			(1 << (n))
+#define BD6107_RGB1CNT1				0x05
+#define BD6107_RGB1CNT2				0x06
+#define BD6107_RGB1CNT3				0x07
+#define BD6107_RGB1CNT4				0x08
+#define BD6107_RGB1CNT5				0x09
+#define BD6107_RGB1FLM				0x0a
+#define BD6107_RGB2CNT1				0x0b
+#define BD6107_RGB2CNT2				0x0c
+#define BD6107_RGB2CNT3				0x0d
+#define BD6107_RGB2CNT4				0x0e
+#define BD6107_RGB2CNT5				0x0f
+#define BD6107_RGB2FLM				0x10
+#define BD6107_PSCONT3				0x11
+#define BD6107_SMMONCNT				0x12
+#define BD6107_DCDCCNT				0x13
+#define BD6107_IOSEL				0x14
+#define BD6107_OUT1				0x15
+#define BD6107_OUT2				0x16
+#define BD6107_MASK1				0x17
+#define BD6107_MASK2				0x18
+#define BD6107_FACTOR1				0x19
+#define BD6107_FACTOR2				0x1a
+#define BD6107_CLRFACT1				0x1b
+#define BD6107_CLRFACT2				0x1c
+#define BD6107_STATE1				0x1d
+#define BD6107_LSIVER				0x1e
+#define BD6107_GRPSEL				0x1f
+#define BD6107_LEDCNT2				0x20
+#define BD6107_LEDCNT3				0x21
+#define BD6107_MCURRENT				0x22
+#define BD6107_MAINCNT1				0x23
+#define BD6107_MAINCNT2				0x24
+#define BD6107_SLOPECNT				0x25
+#define BD6107_MSLOPE				0x26
+#define BD6107_RGBSLOPE				0x27
+#define BD6107_TEST				0x29
+#define BD6107_SFTRST				0x2a
+#define BD6107_SFTRSTGD				0x2b
+
+struct bd6107 {
+	struct i2c_client *client;
+	struct backlight_device *backlight;
+	struct bd6107_platform_data *pdata;
+	struct gpio_desc *reset;
+};
+
+static int bd6107_write(struct bd6107 *bd, u8 reg, u8 data)
+{
+	return i2c_smbus_write_byte_data(bd->client, reg, data);
+}
+
+static int bd6107_backlight_update_status(struct backlight_device *backlight)
+{
+	struct bd6107 *bd = bl_get_data(backlight);
+	int brightness = backlight_get_brightness(backlight);
+
+	if (brightness) {
+		bd6107_write(bd, BD6107_PORTSEL, BD6107_PORTSEL_LEDM(2) |
+			     BD6107_PORTSEL_LEDM(1) | BD6107_PORTSEL_LEDM(0));
+		bd6107_write(bd, BD6107_MAINCNT1, brightness);
+		bd6107_write(bd, BD6107_LEDCNT1, BD6107_LEDCNT1_LEDONOFF1);
+	} else {
+		/* Assert the reset line (gpiolib will handle active low) */
+		gpiod_set_value(bd->reset, 1);
+		msleep(24);
+		gpiod_set_value(bd->reset, 0);
+	}
+
+	return 0;
+}
+
+static bool bd6107_backlight_controls_device(struct backlight_device *backlight,
+					     struct device *display_dev)
+{
+	struct bd6107 *bd = bl_get_data(backlight);
+
+	return !bd->pdata->dev || bd->pdata->dev == display_dev;
+}
+
+static const struct backlight_ops bd6107_backlight_ops = {
+	.options	 = BL_CORE_SUSPENDRESUME,
+	.update_status	 = bd6107_backlight_update_status,
+	.controls_device = bd6107_backlight_controls_device,
+};
+
+static int bd6107_probe(struct i2c_client *client)
+{
+	struct bd6107_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct backlight_device *backlight;
+	struct backlight_properties props;
+	struct bd6107 *bd;
+
+	if (pdata == NULL) {
+		dev_err(&client->dev, "No platform data\n");
+		return -EINVAL;
+	}
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_warn(&client->dev,
+			 "I2C adapter doesn't support I2C_FUNC_SMBUS_BYTE\n");
+		return -EIO;
+	}
+
+	bd = devm_kzalloc(&client->dev, sizeof(*bd), GFP_KERNEL);
+	if (!bd)
+		return -ENOMEM;
+
+	bd->client = client;
+	bd->pdata = pdata;
+
+	/*
+	 * Request the reset GPIO line with GPIOD_OUT_HIGH meaning asserted,
+	 * so in the machine descriptor table (or other hardware description),
+	 * the line should be flagged as active low so this will assert
+	 * the reset.
+	 */
+	bd->reset = devm_gpiod_get(&client->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(bd->reset))
+		return dev_err_probe(&client->dev, PTR_ERR(bd->reset),
+				     "unable to request reset GPIO\n");
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = 128;
+	props.brightness = clamp_t(unsigned int, pdata->def_value, 0,
+				   props.max_brightness);
+
+	backlight = devm_backlight_device_register(&client->dev,
+					      dev_name(&client->dev),
+					      &bd->client->dev, bd,
+					      &bd6107_backlight_ops, &props);
+	if (IS_ERR(backlight)) {
+		dev_err(&client->dev, "failed to register backlight\n");
+		return PTR_ERR(backlight);
+	}
+
+	backlight_update_status(backlight);
+	i2c_set_clientdata(client, backlight);
+
+	return 0;
+}
+
+static void bd6107_remove(struct i2c_client *client)
+{
+	struct backlight_device *backlight = i2c_get_clientdata(client);
+
+	backlight->props.brightness = 0;
+	backlight_update_status(backlight);
+}
+
+static const struct i2c_device_id bd6107_ids[] = {
+	{ .name = "bd6107" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, bd6107_ids);
+
+static struct i2c_driver bd6107_driver = {
+	.driver = {
+		.name = "bd6107",
+	},
+	.probe = bd6107_probe,
+	.remove = bd6107_remove,
+	.id_table = bd6107_ids,
+};
+
+module_i2c_driver(bd6107_driver);
+
+MODULE_DESCRIPTION("Rohm BD6107 Backlight Driver");
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
+MODULE_LICENSE("GPL");