selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 63 insertions, 0 deletions

diff --git a/Documentation/tools/rv/rv.rst b/Documentation/tools/rv/rv.rst
new file mode 100644
index 000000000..cee93dc21
--- /dev/null
+++ b/Documentation/tools/rv/rv.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+==
+rv
+==
+--------------------
+Runtime Verification
+--------------------
+
+:Manual section: 1
+
+SYNOPSIS
+========
+
+**rv** *COMMAND* [*OPTIONS*]
+
+DESCRIPTION
+===========
+
+Runtime Verification (**RV**) is a lightweight (yet rigorous) method
+for formal verification with a practical approach for complex systems.
+Instead of relying on a fine-grained model of a system (e.g., a
+re-implementation a instruction level), RV works by analyzing the trace
+of the system's actual execution, comparing it against a formal
+specification of the system behavior.
+
+The **rv** tool provides the interface for a collection of runtime
+verification (rv) monitors.
+
+COMMANDS
+========
+
+**list**
+
+        List all available monitors.
+
+**mon**
+
+        Run monitor.
+
+OPTIONS
+=======
+
+**-h**, **--help**
+
+        Display the help text.
+
+For other options, see the man page for the corresponding command.
+
+SEE ALSO
+========
+
+**rv-list**\(1), **rv-mon**\(1)
+
+Linux kernel *RV* documentation:
+<https://www.kernel.org/doc/html/latest/trace/rv/index.html>
+
+AUTHOR
+======
+
+Daniel Bristot de Oliveira <bristot@kernel.org>
+
+.. include:: common_appendix.rst