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, 121 insertions, 0 deletions

diff --git a/include/acpi/video.h b/include/acpi/video.h
new file mode 100644
index 000000000..044c46313
--- /dev/null
+++ b/include/acpi/video.h
@@ -0,0 +1,121 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ACPI_VIDEO_H
+#define __ACPI_VIDEO_H
+
+#include <linux/errno.h> /* for ENODEV */
+#include <linux/types.h> /* for bool */
+
+struct acpi_video_brightness_flags {
+	u8 _BCL_no_ac_battery_levels:1;	/* no AC/Battery levels in _BCL */
+	u8 _BCL_reversed:1;		/* _BCL package is in a reversed order */
+	u8 _BQC_use_index:1;		/* _BQC returns an index value */
+};
+
+struct acpi_video_device_brightness {
+	int curr;
+	int count;
+	int *levels;
+	struct acpi_video_brightness_flags flags;
+};
+
+struct acpi_device;
+
+#define ACPI_VIDEO_CLASS	"video"
+
+#define ACPI_VIDEO_DISPLAY_CRT  1
+#define ACPI_VIDEO_DISPLAY_TV   2
+#define ACPI_VIDEO_DISPLAY_DVI  3
+#define ACPI_VIDEO_DISPLAY_LCD  4
+
+#define ACPI_VIDEO_DISPLAY_LEGACY_MONITOR 0x0100
+#define ACPI_VIDEO_DISPLAY_LEGACY_PANEL   0x0110
+#define ACPI_VIDEO_DISPLAY_LEGACY_TV      0x0200
+
+#define ACPI_VIDEO_NOTIFY_SWITCH		0x80
+#define ACPI_VIDEO_NOTIFY_PROBE			0x81
+#define ACPI_VIDEO_NOTIFY_CYCLE			0x82
+#define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT		0x83
+#define ACPI_VIDEO_NOTIFY_PREV_OUTPUT		0x84
+#define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS	0x85
+#define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS	0x86
+#define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS	0x87
+#define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS	0x88
+#define ACPI_VIDEO_NOTIFY_DISPLAY_OFF		0x89
+
+enum acpi_backlight_type {
+	acpi_backlight_undef = -1,
+	acpi_backlight_none = 0,
+	acpi_backlight_video,
+	acpi_backlight_vendor,
+	acpi_backlight_native,
+	acpi_backlight_nvidia_wmi_ec,
+	acpi_backlight_apple_gmux,
+	acpi_backlight_dell_uart,
+};
+
+#if IS_ENABLED(CONFIG_ACPI_VIDEO)
+extern int acpi_video_register(void);
+extern void acpi_video_unregister(void);
+extern void acpi_video_register_backlight(void);
+extern int acpi_video_get_edid(struct acpi_device *device, int type,
+			       int device_id, void **edid);
+/*
+ * Note: The value returned by acpi_video_handles_brightness_key_presses()
+ * may change over time and should not be cached.
+ */
+extern bool acpi_video_handles_brightness_key_presses(void);
+extern int acpi_video_get_levels(struct acpi_device *device,
+				 struct acpi_video_device_brightness **dev_br,
+				 int *pmax_level);
+
+extern enum acpi_backlight_type __acpi_video_get_backlight_type(bool native,
+								bool *auto_detect);
+
+static inline enum acpi_backlight_type acpi_video_get_backlight_type(void)
+{
+	return __acpi_video_get_backlight_type(false, NULL);
+}
+
+/*
+ * This function MUST only be called by GPU drivers to check if the driver
+ * should register a backlight class device. This function not only checks
+ * if a GPU native backlight device should be registered it *also* tells
+ * the ACPI video-detect code that native GPU backlight control is available.
+ * Therefor calling this from any place other then the GPU driver is wrong!
+ * To check if GPU native backlight control is used in other places instead use:
+ *   if (acpi_video_get_backlight_type() == acpi_backlight_native) { ... }
+ */
+static inline bool acpi_video_backlight_use_native(void)
+{
+	return __acpi_video_get_backlight_type(true, NULL) == acpi_backlight_native;
+}
+#else
+static inline int acpi_video_register(void) { return -ENODEV; }
+static inline void acpi_video_unregister(void) { return; }
+static inline void acpi_video_register_backlight(void) { return; }
+static inline int acpi_video_get_edid(struct acpi_device *device, int type,
+				      int device_id, void **edid)
+{
+	return -ENODEV;
+}
+static inline enum acpi_backlight_type acpi_video_get_backlight_type(void)
+{
+	return acpi_backlight_vendor;
+}
+static inline bool acpi_video_backlight_use_native(void)
+{
+	return true;
+}
+static inline bool acpi_video_handles_brightness_key_presses(void)
+{
+	return false;
+}
+static inline int acpi_video_get_levels(struct acpi_device *device,
+			struct acpi_video_device_brightness **dev_br,
+			int *pmax_level)
+{
+	return -ENODEV;
+}
+#endif
+
+#endif