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, 51 insertions, 0 deletions

diff --git a/drivers/clk/meson/vclk.h b/drivers/clk/meson/vclk.h
new file mode 100644
index 000000000..20b0b181d
--- /dev/null
+++ b/drivers/clk/meson/vclk.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Neil Armstrong <neil.armstrong@linaro.org>
+ */
+
+#ifndef __VCLK_H
+#define __VCLK_H
+
+#include "clk-regmap.h"
+#include "parm.h"
+
+/**
+ * struct meson_vclk_gate_data - vclk_gate regmap backed specific data
+ *
+ * @enable:	vclk enable field
+ * @reset:	vclk reset field
+ * @flags:	hardware-specific flags
+ *
+ * Flags:
+ * Same as clk_gate except CLK_GATE_HIWORD_MASK which is ignored
+ */
+struct meson_vclk_gate_data {
+	struct parm enable;
+	struct parm reset;
+	u8 flags;
+};
+
+extern const struct clk_ops meson_vclk_gate_ops;
+
+/**
+ * struct meson_vclk_div_data - vclk_div regmap back specific data
+ *
+ * @div:	divider field
+ * @enable:	vclk divider enable field
+ * @reset:	vclk divider reset field
+ * @table:	array of value/divider pairs, last entry should have div = 0
+ *
+ * Flags:
+ * Same as clk_divider except CLK_DIVIDER_HIWORD_MASK which is ignored
+ */
+struct meson_vclk_div_data {
+	struct parm div;
+	struct parm enable;
+	struct parm reset;
+	const struct clk_div_table *table;
+	u8 flags;
+};
+
+extern const struct clk_ops meson_vclk_div_ops;
+
+#endif /* __VCLK_H */