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/sound/sdca_regmap.h b/include/sound/sdca_regmap.h
new file mode 100644
index 000000000..792540a53
--- /dev/null
+++ b/include/sound/sdca_regmap.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ *
+ * Copyright (C) 2025 Cirrus Logic, Inc. and
+ *                    Cirrus Logic International Semiconductor Ltd.
+ */
+
+#ifndef __SDCA_REGMAP_H__
+#define __SDCA_REGMAP_H__
+
+struct device;
+struct sdca_function_data;
+struct regmap;
+struct reg_default;
+
+bool sdca_regmap_readable(struct sdca_function_data *function, unsigned int reg);
+bool sdca_regmap_writeable(struct sdca_function_data *function, unsigned int reg);
+bool sdca_regmap_volatile(struct sdca_function_data *function, unsigned int reg);
+bool sdca_regmap_deferrable(struct sdca_function_data *function, unsigned int reg);
+int sdca_regmap_mbq_size(struct sdca_function_data *function, unsigned int reg);
+
+int sdca_regmap_count_constants(struct device *dev, struct sdca_function_data *function);
+int sdca_regmap_populate_constants(struct device *dev, struct sdca_function_data *function,
+				   struct reg_default *consts);
+
+int sdca_regmap_write_defaults(struct device *dev, struct regmap *regmap,
+			       struct sdca_function_data *function);
+int sdca_regmap_write_init(struct device *dev, struct regmap *regmap,
+			   struct sdca_function_data *function);
+
+#endif // __SDCA_REGMAP_H__