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, 20 insertions, 0 deletions

diff --git a/scripts/kconfig/mnconf-common.h b/scripts/kconfig/mnconf-common.h
new file mode 100644
index 000000000..53bd7292e
--- /dev/null
+++ b/scripts/kconfig/mnconf-common.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef MNCONF_COMMON_H
+#define MNCONF_COMMON_H
+
+#include <stddef.h>
+
+#include <list_types.h>
+
+struct search_data {
+	struct list_head *head;
+	struct menu *target;
+};
+
+extern int jump_key_char;
+
+int next_jump_key(int key);
+int handle_search_keys(int key, size_t start, size_t end, void *_data);
+int get_jump_key_char(void);
+
+#endif /* MNCONF_COMMON_H */