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, 33 insertions, 0 deletions

diff --git a/include/kunit/clk.h b/include/kunit/clk.h
new file mode 100644
index 000000000..f226044cc
--- /dev/null
+++ b/include/kunit/clk.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CLK_KUNIT_H
+#define _CLK_KUNIT_H
+
+struct clk;
+struct clk_hw;
+struct device;
+struct device_node;
+struct of_phandle_args;
+struct kunit;
+
+struct clk *
+clk_get_kunit(struct kunit *test, struct device *dev, const char *con_id);
+struct clk *
+of_clk_get_kunit(struct kunit *test, struct device_node *np, int index);
+
+struct clk *
+clk_hw_get_clk_kunit(struct kunit *test, struct clk_hw *hw, const char *con_id);
+struct clk *
+clk_hw_get_clk_prepared_enabled_kunit(struct kunit *test, struct clk_hw *hw,
+				      const char *con_id);
+
+int clk_prepare_enable_kunit(struct kunit *test, struct clk *clk);
+
+int clk_hw_register_kunit(struct kunit *test, struct device *dev, struct clk_hw *hw);
+int of_clk_hw_register_kunit(struct kunit *test, struct device_node *node,
+			     struct clk_hw *hw);
+
+int of_clk_add_hw_provider_kunit(struct kunit *test, struct device_node *np,
+				 struct clk_hw *(*get)(struct of_phandle_args *clkspec, void *data),
+				 void *data);
+
+#endif