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, 105 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-wacom b/Documentation/ABI/testing/sysfs-driver-wacom
new file mode 100644
index 000000000..16acaa571
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-wacom
@@ -0,0 +1,105 @@
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/speed
+Date:		April 2010
+KernelVersion:	2.6.35
+Contact:	linux-bluetooth@vger.kernel.org
+Description:
+		The /sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/speed file
+		controls reporting speed of Wacom bluetooth tablet. Reading
+		from this file returns 1 if tablet reports in high speed mode
+		or 0 otherwise. Writing to this file one of these values
+		switches reporting speed.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_led/led
+Date:		August 2014
+Contact:	linux-input@vger.kernel.org
+Description:
+		Attribute group for control of the status LEDs and the OLEDs.
+		This attribute group is only available for Intuos 4 M, L,
+		and XL (with LEDs and OLEDs), Intuos 4 WL, Intuos 5 (LEDs only),
+		Intuos Pro (LEDs only) and Cintiq 21UX2 and Cintiq 24HD
+		(LEDs only). Therefore its presence implicitly signifies the
+		presence of said LEDs and OLEDs on the tablet device.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_led/status0_luminance
+Date:		August 2014
+Contact:	linux-input@vger.kernel.org
+Description:
+		<obsoleted by the LED class API now exported by the driver>
+		Writing to this file sets the status LED luminance (1..127)
+		when the stylus does not touch the tablet surface, and no
+		button is pressed on the stylus. This luminance level is
+		normally lower than the level when a button is pressed.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_led/status1_luminance
+Date:		August 2014
+Contact:	linux-input@vger.kernel.org
+Description:
+		<obsoleted by the LED class API now exported by the driver>
+		Writing to this file sets the status LED luminance (1..127)
+		when the stylus touches the tablet surface, or any button is
+		pressed on the stylus.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_led/status_led0_select
+Date:		August 2014
+Contact:	linux-input@vger.kernel.org
+Description:
+		<obsoleted by the LED class API now exported by the driver>
+		Writing to this file sets which one of the four (for Intuos 4
+		and Intuos 5) or of the right four (for Cintiq 21UX2 and Cintiq
+		24HD) status LEDs is active (0..3). The other three LEDs on the
+		same side are always inactive.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_led/status_led1_select
+Date:		August 2014
+Contact:	linux-input@vger.kernel.org
+Description:
+		<obsoleted by the LED class API now exported by the driver>
+		Writing to this file sets which one of the left four (for Cintiq 21UX2
+		and Cintiq 24HD) status LEDs is active (0..3). The other three LEDs on
+		the left are always inactive.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_led/buttons_luminance
+Date:		August 2014
+Contact:	linux-input@vger.kernel.org
+Description:
+		Writing to this file sets the overall luminance level (0..15)
+		of all eight button OLED displays.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_led/button<n>_rawimg
+Date:		August 2014
+Contact:	linux-input@vger.kernel.org
+Description:
+		When writing a 1024 byte raw image in Wacom Intuos 4
+		interleaving format to the file, the image shows up on Button N
+		of the device. The image is a 64x32 pixel 4-bit gray image. The
+		1024 byte binary is split up into 16x 64 byte chunks. Each 64
+		byte chunk encodes the image data for two consecutive lines on
+		the display. The low nibble of each byte contains the first
+		line, and the high nibble contains the second line.
+		When the Wacom Intuos 4 is connected over Bluetooth, the
+		image has to contain 256 bytes (64x32 px 1 bit colour).
+		The format is also scrambled, like in the USB mode, and it can
+		be summarized by converting::
+
+					    76543210 into GECA6420.
+					    HGFEDCBA      HFDB7531
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_remote/unpair_remote
+Date:		July 2015
+Contact:	linux-input@vger.kernel.org
+Description:
+		Writing the character sequence '*' followed by a newline to
+		this file will delete all of the current pairings on the
+		device. Other character sequences are reserved. This file is
+		write only.
+
+What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/wacom_remote/<serial_number>/remote_mode
+Date:		July 2015
+Contact:	linux-input@vger.kernel.org
+Description:
+		<obsoleted by the LED class API now exported by the driver>
+		Reading from this file reports the mode status of the
+		remote as indicated by the LED lights on the device. If no
+		reports have been received from the paired device, reading
+		from this file will report '-1'. The mode is read-only
+		and cannot be set through the driver.