bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 56 insertions, 0 deletions

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 <marcus.folkesson@gmail.com>
+
+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 <devnr>
+
+To print all input events from input `devnr`.
+
+References
+==========
+
+.. [1] https://www.kraxel.org/cgit/input/