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, 36 insertions, 0 deletions

diff --git a/drivers/clk/visconti/reset.h b/drivers/clk/visconti/reset.h
new file mode 100644
index 000000000..229dffcbd
--- /dev/null
+++ b/drivers/clk/visconti/reset.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Toshiba ARM SoC reset controller driver
+ *
+ * Copyright (c) 2021 TOSHIBA CORPORATION
+ *
+ * Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
+ */
+
+#ifndef _VISCONTI_RESET_H_
+#define _VISCONTI_RESET_H_
+
+#include <linux/reset-controller.h>
+
+struct visconti_reset_data {
+	u32	rson_offset;
+	u32	rsoff_offset;
+	u8	rs_idx;
+};
+
+struct visconti_reset {
+	struct reset_controller_dev rcdev;
+	struct regmap *regmap;
+	const struct visconti_reset_data *resets;
+	spinlock_t *lock;
+};
+
+extern const struct reset_control_ops visconti_reset_ops;
+
+int visconti_register_reset_controller(struct device *dev,
+				       struct regmap *regmap,
+				       const struct visconti_reset_data *resets,
+				       unsigned int num_resets,
+				       const struct reset_control_ops *reset_ops,
+				       spinlock_t *lock);
+#endif /* _VISCONTI_RESET_H_ */