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, 42 insertions, 0 deletions

diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst
new file mode 100644
index 000000000..59cbb77b3
--- /dev/null
+++ b/Documentation/dev-tools/index.rst
@@ -0,0 +1,42 @@
+================================
+Development tools for the kernel
+================================
+
+This document is a collection of documents about development tools that can
+be used to work on the kernel. For now, the documents have been pulled
+together without any significant effort to integrate them into a coherent
+whole; patches welcome!
+
+A brief overview of testing-specific tools can be found in
+Documentation/dev-tools/testing-overview.rst
+
+Tools that are specific to debugging can be found in
+Documentation/process/debugging/index.rst
+
+.. toctree::
+   :caption: Table of contents
+   :maxdepth: 2
+
+   testing-overview
+   checkpatch
+   clang-format
+   coccinelle
+   context-analysis
+   sparse
+   kcov
+   gcov
+   kasan
+   kmsan
+   ubsan
+   kmemleak
+   kcsan
+   lkmm/index
+   kfence
+   kselftest
+   kunit/index
+   ktap
+   checkuapi
+   gpio-sloppy-logic-analyzer
+   autofdo
+   propeller
+   container