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, 52 insertions, 0 deletions

diff --git a/Documentation/tools/rtla/rtla.rst b/Documentation/tools/rtla/rtla.rst
new file mode 100644
index 000000000..6df1296b8
--- /dev/null
+++ b/Documentation/tools/rtla/rtla.rst
@@ -0,0 +1,52 @@
+=========
+rtla
+=========
+--------------------------------
+Real-time Linux Analysis tool
+--------------------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+**rtla** *COMMAND* [*OPTIONS*]
+
+DESCRIPTION
+===========
+The **rtla** is a meta-tool that includes a set of commands that aims to
+analyze the real-time properties of Linux. But instead of testing Linux
+as a black box, **rtla** leverages kernel tracing capabilities to provide
+precise information about the properties and root causes of unexpected
+results.
+
+COMMANDS
+========
+**hwnoise**
+
+        Detect and quantify hardware-related noise.
+
+**osnoise**
+
+        Gives information about the operating system noise (osnoise).
+
+**timerlat**
+
+        Measures the IRQ and thread timer latency.
+
+OPTIONS
+=======
+**-h**, **--help**
+
+        Display the help text.
+
+For other options, see the man page for the corresponding command.
+
+SEE ALSO
+========
+**rtla-hwnoise**\(1), **rtla-osnoise**\(1), **rtla-timerlat**\(1)
+
+AUTHOR
+======
+Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.txt