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, 17 insertions, 0 deletions

diff --git a/Documentation/driver-api/80211/introduction.rst b/Documentation/driver-api/80211/introduction.rst
new file mode 100644
index 000000000..4938fa876
--- /dev/null
+++ b/Documentation/driver-api/80211/introduction.rst
@@ -0,0 +1,17 @@
+============
+Introduction
+============
+
+Explaining wireless 802.11 networking in the Linux kernel
+
+Copyright 2007-2009 Johannes Berg
+
+These books attempt to give a description of the various subsystems
+that play a role in 802.11 wireless networking in Linux. Since these
+books are for kernel developers they attempts to document the
+structures and functions used in the kernel as well as giving a
+higher-level overview.
+
+The reader is expected to be familiar with the 802.11 standard as
+published by the IEEE in 802.11-2007 (or possibly later versions).
+References to this standard will be given as "802.11-2007 8.1.5".