From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- Documentation/input/devices/pxrc.rst | 56 ++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 Documentation/input/devices/pxrc.rst (limited to 'Documentation/input/devices/pxrc.rst') diff --git a/Documentation/input/devices/pxrc.rst b/Documentation/input/devices/pxrc.rst new file mode 100644 index 000000000..5a86df4ad --- /dev/null +++ b/Documentation/input/devices/pxrc.rst @@ -0,0 +1,56 @@ +======================================================= +pxrc - PhoenixRC Flight Controller Adapter +======================================================= + +:Author: Marcus Folkesson + +This driver let you use your own RC controller plugged into the +adapter that comes with PhoenixRC or other compatible adapters. + +The adapter supports 7 analog channels and 1 digital input switch. + +Notes +===== + +Many RC controllers is able to configure which stick goes to which channel. +This is also configurable in most simulators, so a matching is not necessary. + +The driver is generating the following input event for analog channels: + ++---------+----------------+ +| Channel | Event | ++=========+================+ +| 1 | ABS_X | ++---------+----------------+ +| 2 | ABS_Y | ++---------+----------------+ +| 3 | ABS_RX | ++---------+----------------+ +| 4 | ABS_RY | ++---------+----------------+ +| 5 | ABS_RUDDER | ++---------+----------------+ +| 6 | ABS_THROTTLE | ++---------+----------------+ +| 7 | ABS_MISC | ++---------+----------------+ + +The digital input switch is generated as an `BTN_A` event. + +Manual Testing +============== + +To test this driver's functionality you may use `input-event` which is part of +the `input layer utilities` suite [1]_. + +For example:: + + > modprobe pxrc + > input-events + +To print all input events from input `devnr`. + +References +========== + +.. [1] https://www.kraxel.org/cgit/input/ -- cgit v1.3.1