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, 234 insertions, 0 deletions

diff --git a/Documentation/input/devices/xpad.rst b/Documentation/input/devices/xpad.rst
new file mode 100644
index 000000000..a480bc781
--- /dev/null
+++ b/Documentation/input/devices/xpad.rst
@@ -0,0 +1,234 @@
+=======================================================
+xpad - Linux USB driver for Xbox compatible controllers
+=======================================================
+
+This driver exposes all first-party and third-party Xbox compatible
+controllers. It has a long history and has enjoyed considerable usage
+as Windows' xinput library caused most PC games to focus on Xbox
+controller compatibility.
+
+Due to backwards compatibility all buttons are reported as digital.
+This only affects Original Xbox controllers. All later controller models
+have only digital face buttons.
+
+Rumble is supported on some models of Xbox 360 controllers but not of
+Original Xbox controllers nor on Xbox One controllers. As of writing
+the Xbox One's rumble protocol has not been reverse-engineered but in
+the future could be supported.
+
+
+Notes
+=====
+
+The number of buttons/axes reported varies based on 3 things:
+
+- if you are using a known controller
+- if you are using a known dance pad
+- if using an unknown device (one not listed below), what you set in the
+  module configuration for "Map D-PAD to buttons rather than axes for unknown
+  pads" (module option dpad_to_buttons)
+
+If you set dpad_to_buttons to N and you are using an unknown device
+the driver will map the directional pad to axes (X/Y).
+If you said Y it will map the d-pad to buttons, which is needed for dance
+style games to function correctly. The default is Y.
+
+dpad_to_buttons has no effect for known pads. A erroneous commit message
+claimed dpad_to_buttons could be used to force behavior on known devices.
+This is not true. Both dpad_to_buttons and triggers_to_buttons only affect
+unknown controllers.
+
+
+Normal Controllers
+------------------
+
+With a normal controller, the directional pad is mapped to its own X/Y axes.
+The jstest-program from joystick-1.2.15 (jstest-version 2.1.0) will report 8
+axes and 10 buttons.
+
+All 8 axes work, though they all have the same range (-32768..32767)
+and the zero-setting is not correct for the triggers (I don't know if that
+is some limitation of jstest, since the input device setup should be fine. I
+didn't have a look at jstest itself yet).
+
+All of the 10 buttons work (in digital mode). The six buttons on the
+right side (A, B, X, Y, black, white) are said to be "analog" and
+report their values as 8 bit unsigned, not sure what this is good for.
+
+I tested the controller with quake3, and configuration and
+in game functionality were OK. However, I find it rather difficult to
+play first person shooters with a pad. Your mileage may vary.
+
+
+Xbox Dance Pads
+---------------
+
+When using a known dance pad, jstest will report 6 axes and 14 buttons.
+
+For dance style pads (like the redoctane pad) several changes
+have been made.  The old driver would map the d-pad to axes, resulting
+in the driver being unable to report when the user was pressing both
+left+right or up+down, making DDR style games unplayable.
+
+Known dance pads automatically map the d-pad to buttons and will work
+correctly out of the box.
+
+If your dance pad is recognized by the driver but is using axes instead
+of buttons, see section 0.3 - Unknown Controllers
+
+I've tested this with Stepmania, and it works quite well.
+
+
+Unknown Controllers
+-------------------
+
+If you have an unknown Xbox controller, it should work just fine with
+the default settings.
+
+HOWEVER if you have an unknown dance pad not listed below, it will not
+work UNLESS you set "dpad_to_buttons" to 1 in the module configuration.
+
+
+USB adapters
+============
+
+All generations of Xbox controllers speak USB over the wire.
+
+- Original Xbox controllers use a proprietary connector and require adapters.
+- Wireless Xbox 360 controllers require a 'Xbox 360 Wireless Gaming Receiver
+  for Windows'
+- Wired Xbox 360 controllers use standard USB connectors.
+- Xbox One controllers can be wireless but speak Wi-Fi Direct and are not
+  yet supported.
+- Xbox One controllers can be wired and use standard Micro-USB connectors.
+
+
+
+Original Xbox USB adapters
+--------------------------
+
+Using this driver with an Original Xbox controller requires an
+adapter cable to break out the proprietary connector's pins to USB.
+You can buy these online fairly cheap, or build your own.
+
+Such a cable is pretty easy to build. The Controller itself is a USB
+compound device (a hub with three ports for two expansion slots and
+the controller device) with the only difference in a nonstandard connector
+(5 pins vs. 4 on standard USB 1.0 connectors).
+
+You just need to solder a USB connector onto the cable and keep the
+yellow wire unconnected. The other pins have the same order on both
+connectors so there is no magic to it. Detailed info on these matters
+can be found on the net ([1]_, [2]_, [3]_).
+
+Thanks to the trip splitter found on the cable you don't even need to cut the
+original one. You can buy an extension cable and cut that instead. That way,
+you can still use the controller with your Xbox, if you have one ;)
+
+
+
+Driver Installation
+===================
+
+Once you have the adapter cable, if needed, and the controller connected
+the xpad module should be auto loaded. To confirm you can cat
+/sys/kernel/debug/usb/devices. There should be an entry like those:
+
+.. code-block:: none
+   :caption: dump from InterAct PowerPad Pro (Germany)
+
+    T:  Bus=01 Lev=03 Prnt=04 Port=00 Cnt=01 Dev#=  5 Spd=12  MxCh= 0
+    D:  Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=32 #Cfgs=  1
+    P:  Vendor=05fd ProdID=107a Rev= 1.00
+    C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA
+    I:  If#= 0 Alt= 0 #EPs= 2 Cls=58(unk. ) Sub=42 Prot=00 Driver=(none)
+    E:  Ad=81(I) Atr=03(Int.) MxPS=  32 Ivl= 10ms
+    E:  Ad=02(O) Atr=03(Int.) MxPS=  32 Ivl= 10ms
+
+.. code-block:: none
+   :caption: dump from Redoctane Xbox Dance Pad (US)
+
+    T:  Bus=01 Lev=02 Prnt=09 Port=00 Cnt=01 Dev#= 10 Spd=12  MxCh= 0
+    D:  Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
+    P:  Vendor=0c12 ProdID=8809 Rev= 0.01
+    S:  Product=XBOX DDR
+    C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA
+    I:  If#= 0 Alt= 0 #EPs= 2 Cls=58(unk. ) Sub=42 Prot=00 Driver=xpad
+    E:  Ad=82(I) Atr=03(Int.) MxPS=  32 Ivl=4ms
+    E:  Ad=02(O) Atr=03(Int.) MxPS=  32 Ivl=4ms
+
+
+Supported Controllers
+=====================
+
+For a full list of supported controllers and associated vendor and product
+IDs see the xpad_device[] array\ [4]_.
+
+As of the historic version 0.0.6 (2006-10-10) the following devices
+were supported::
+
+ original Microsoft XBOX controller (US),    vendor=0x045e, product=0x0202
+ smaller  Microsoft XBOX controller (US),    vendor=0x045e, product=0x0289
+ original Microsoft XBOX controller (Japan), vendor=0x045e, product=0x0285
+ InterAct PowerPad Pro (Germany),            vendor=0x05fd, product=0x107a
+ RedOctane Xbox Dance Pad (US),              vendor=0x0c12, product=0x8809
+
+Unrecognized models of Xbox controllers should function as Generic
+Xbox controllers. Unrecognized Dance Pad controllers require setting
+the module option 'dpad_to_buttons'.
+
+If you have an unrecognized controller please see 0.3 - Unknown Controllers
+
+
+Manual Testing
+==============
+
+To test this driver's functionality you may use 'jstest'.
+
+For example::
+
+    > modprobe xpad
+    > modprobe joydev
+    > jstest /dev/js0
+
+If you're using a normal controller, there should be a single line showing
+18 inputs (8 axes, 10 buttons), and its values should change if you move
+the sticks and push the buttons.  If you're using a dance pad, it should
+show 20 inputs (6 axes, 14 buttons).
+
+It works? Voila, you're done ;)
+
+
+
+Thanks
+======
+
+I have to thank ITO Takayuki for the detailed info on his site
+    http://euc.jp/periphs/xbox-controller.ja.html.
+
+His useful info and both the usb-skeleton as well as the iforce input driver
+(Greg Kroah-Hartmann; Vojtech Pavlik) helped a lot in rapid prototyping
+the basic functionality.
+
+
+
+References
+==========
+
+.. [1] http://euc.jp/periphs/xbox-controller.ja.html (ITO Takayuki)
+.. [2] http://xpad.xbox-scene.com/
+.. [3] http://www.markosweb.com/www/xboxhackz.com/
+.. [4] https://elixir.bootlin.com/linux/latest/ident/xpad_device
+
+
+Historic Edits
+==============
+
+2002-07-16 - Marko Friedemann <mfr@bmx-chemnitz.de>
+ - original doc
+
+2005-03-19 - Dominic Cerquetti <binary1230@yahoo.com>
+ - added stuff for dance pads, new d-pad->axes mappings
+
+Later changes may be viewed with
+'git log --follow Documentation/input/devices/xpad.rst'