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, 70 insertions, 0 deletions

diff --git a/drivers/clk/actions/owl-divider.h b/drivers/clk/actions/owl-divider.h
new file mode 100644
index 000000000..1d3bb4e58
--- /dev/null
+++ b/drivers/clk/actions/owl-divider.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+//
+// OWL divider clock driver
+//
+// Copyright (c) 2014 Actions Semi Inc.
+// Author: David Liu <liuwei@actions-semi.com>
+//
+// Copyright (c) 2018 Linaro Ltd.
+// Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+
+#ifndef _OWL_DIVIDER_H_
+#define _OWL_DIVIDER_H_
+
+#include "owl-common.h"
+
+struct owl_divider_hw {
+	u32			reg;
+	u8			shift;
+	u8			width;
+	u8			div_flags;
+	struct clk_div_table	*table;
+};
+
+struct owl_divider {
+	struct owl_divider_hw	div_hw;
+	struct owl_clk_common	common;
+};
+
+#define OWL_DIVIDER_HW(_reg, _shift, _width, _div_flags, _table)	\
+	{								\
+		.reg		= _reg,					\
+		.shift		= _shift,				\
+		.width		= _width,				\
+		.div_flags	= _div_flags,				\
+		.table		= _table,				\
+	}
+
+#define OWL_DIVIDER(_struct, _name, _parent, _reg,			\
+		    _shift, _width, _table, _div_flags, _flags)		\
+	struct owl_divider _struct = {					\
+		.div_hw	= OWL_DIVIDER_HW(_reg, _shift, _width,		\
+					 _div_flags, _table),		\
+		.common = {						\
+			.regmap		= NULL,				\
+			.hw.init	= CLK_HW_INIT(_name,		\
+						      _parent,		\
+						      &owl_divider_ops,	\
+						      _flags),		\
+		},							\
+	}
+
+static inline struct owl_divider *hw_to_owl_divider(struct clk_hw *hw)
+{
+	struct owl_clk_common *common = hw_to_owl_clk_common(hw);
+
+	return container_of(common, struct owl_divider, common);
+}
+
+unsigned long owl_divider_helper_recalc_rate(struct owl_clk_common *common,
+					 const struct owl_divider_hw *div_hw,
+					 unsigned long parent_rate);
+
+int owl_divider_helper_set_rate(const struct owl_clk_common *common,
+				const struct owl_divider_hw *div_hw,
+				unsigned long rate,
+				unsigned long parent_rate);
+
+extern const struct clk_ops owl_divider_ops;
+
+#endif /* _OWL_DIVIDER_H_ */