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, 85 insertions, 0 deletions

diff --git a/drivers/clk/sprd/div.h b/drivers/clk/sprd/div.h
new file mode 100644
index 000000000..a0bcad804
--- /dev/null
+++ b/drivers/clk/sprd/div.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+//
+// Spreadtrum divider clock driver
+//
+// Copyright (C) 2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#ifndef _SPRD_DIV_H_
+#define _SPRD_DIV_H_
+
+#include "common.h"
+
+/**
+ * struct sprd_div_internal - Internal divider description
+ * @shift: Bit offset of the divider in its register
+ * @width: Width of the divider field in its register
+ *
+ * That structure represents a single divider, and is meant to be
+ * embedded in other structures representing the various clock
+ * classes.
+ */
+struct sprd_div_internal {
+	s32	offset;
+	u8	shift;
+	u8	width;
+};
+
+#define _SPRD_DIV_CLK(_offset, _shift, _width)	\
+	{				\
+		.offset = _offset,	\
+		.shift	= _shift,	\
+		.width	= _width,	\
+	}
+
+struct sprd_div {
+	struct sprd_div_internal	div;
+	struct sprd_clk_common	common;
+};
+
+#define SPRD_DIV_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, _offset,	\
+				_shift, _width, _flags, _fn)		\
+	struct sprd_div _struct = {					\
+		.div	= _SPRD_DIV_CLK(_offset, _shift, _width),	\
+		.common	= {						\
+			.regmap		= NULL,				\
+			.reg		= _reg,				\
+			.hw.init	= _fn(_name, _parent,		\
+					      &sprd_div_ops, _flags),	\
+		}							\
+	}
+
+#define SPRD_DIV_CLK(_struct, _name, _parent, _reg,			\
+		     _shift, _width, _flags)				\
+	SPRD_DIV_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, 0x0,	\
+				_shift, _width, _flags, CLK_HW_INIT)
+
+#define SPRD_DIV_CLK_FW_NAME(_struct, _name, _parent, _reg,		\
+			_shift, _width, _flags)				\
+	SPRD_DIV_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, 0x0,	\
+				_shift, _width, _flags, CLK_HW_INIT_FW_NAME)
+
+#define SPRD_DIV_CLK_HW(_struct, _name, _parent, _reg,			\
+			_shift, _width, _flags)				\
+	SPRD_DIV_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, 0x0,	\
+				_shift, _width, _flags, CLK_HW_INIT_HW)
+
+static inline struct sprd_div *hw_to_sprd_div(const struct clk_hw *hw)
+{
+	struct sprd_clk_common *common = hw_to_sprd_clk_common(hw);
+
+	return container_of(common, struct sprd_div, common);
+}
+
+unsigned long sprd_div_helper_recalc_rate(struct sprd_clk_common *common,
+					  const struct sprd_div_internal *div,
+					  unsigned long parent_rate);
+
+int sprd_div_helper_set_rate(const struct sprd_clk_common *common,
+			     const struct sprd_div_internal *div,
+			     unsigned long rate,
+			     unsigned long parent_rate);
+
+extern const struct clk_ops sprd_div_ops;
+
+#endif /* _SPRD_DIV_H_ */