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, 50 insertions, 0 deletions

diff --git a/include/kunit/attributes.h b/include/kunit/attributes.h
new file mode 100644
index 000000000..bc76a0b78
--- /dev/null
+++ b/include/kunit/attributes.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KUnit API to save and access test attributes
+ *
+ * Copyright (C) 2023, Google LLC.
+ * Author: Rae Moar <rmoar@google.com>
+ */
+
+#ifndef _KUNIT_ATTRIBUTES_H
+#define _KUNIT_ATTRIBUTES_H
+
+/*
+ * struct kunit_attr_filter - representation of attributes filter with the
+ * attribute object and string input
+ */
+struct kunit_attr_filter {
+	struct kunit_attr *attr;
+	char *input;
+};
+
+/*
+ * Returns the name of the filter's attribute.
+ */
+const char *kunit_attr_filter_name(struct kunit_attr_filter filter);
+
+/*
+ * Print all test attributes for a test case or suite.
+ * Output format for test cases: "# <test_name>.<attribute>: <value>"
+ * Output format for test suites: "# <attribute>: <value>"
+ */
+void kunit_print_attr(void *test_or_suite, bool is_test, unsigned int test_level);
+
+/*
+ * Returns the number of fitlers in input.
+ */
+int kunit_get_filter_count(char *input);
+
+/*
+ * Parse attributes filter input and return an objects containing the
+ * attribute object and the string input of the next filter.
+ */
+struct kunit_attr_filter kunit_next_attr_filter(char **filters, int *err);
+
+/*
+ * Returns a copy of the suite containing only tests that pass the filter.
+ */
+struct kunit_suite *kunit_filter_attr_tests(const struct kunit_suite *const suite,
+		struct kunit_attr_filter filter, char *action, int *err);
+
+#endif /* _KUNIT_ATTRIBUTES_H */