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, 54 insertions, 0 deletions

diff --git a/drivers/clk/versatile/icst.h b/drivers/clk/versatile/icst.h
new file mode 100644
index 000000000..29622768b
--- /dev/null
+++ b/drivers/clk/versatile/icst.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
+ *
+ *  Support functions for calculating clocks/divisors for the ICST
+ *  clock generators.  See https://www.idt.com/ for more information
+ *  on these devices.
+ */
+#ifndef ICST_H
+#define ICST_H
+
+struct icst_params {
+	unsigned long	ref;
+	unsigned long	vco_max;	/* inclusive */
+	unsigned long	vco_min;	/* exclusive */
+	unsigned short	vd_min;		/* inclusive */
+	unsigned short	vd_max;		/* inclusive */
+	unsigned char	rd_min;		/* inclusive */
+	unsigned char	rd_max;		/* inclusive */
+	const unsigned char *s2div;	/* chip specific s2div array */
+	const unsigned char *idx2s;	/* chip specific idx2s array */
+};
+
+struct icst_vco {
+	unsigned short	v;
+	unsigned char	r;
+	unsigned char	s;
+};
+
+unsigned long icst_hz(const struct icst_params *p, struct icst_vco vco);
+struct icst_vco icst_hz_to_vco(const struct icst_params *p, unsigned long freq);
+
+/*
+ * ICST307 VCO frequency must be between 6MHz and 200MHz (3.3 or 5V).
+ * This frequency is pre-output divider.
+ */
+#define ICST307_VCO_MIN	6000000
+#define ICST307_VCO_MAX	200000000
+
+extern const unsigned char icst307_s2div[];
+extern const unsigned char icst307_idx2s[];
+
+/*
+ * ICST525 VCO frequency must be between 10MHz and 200MHz (3V) or 320MHz (5V).
+ * This frequency is pre-output divider.
+ */
+#define ICST525_VCO_MIN		10000000
+#define ICST525_VCO_MAX_3V	200000000
+#define ICST525_VCO_MAX_5V	320000000
+
+extern const unsigned char icst525_s2div[];
+extern const unsigned char icst525_idx2s[];
+
+#endif