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, 41 insertions, 0 deletions

diff --git a/drivers/clk/versatile/clk-icst.h b/drivers/clk/versatile/clk-icst.h
new file mode 100644
index 000000000..1a119ef11
--- /dev/null
+++ b/drivers/clk/versatile/clk-icst.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+struct regmap;
+
+/**
+ * enum icst_control_type - the type of ICST control register
+ */
+enum icst_control_type {
+	ICST_VERSATILE, /* The standard type, all control bits available */
+	ICST_INTEGRATOR_AP_CM, /* Only 8 bits of VDW available */
+	ICST_INTEGRATOR_AP_SYS, /* Only 8 bits of VDW available */
+	ICST_INTEGRATOR_AP_PCI, /* Odd bit pattern storage */
+	ICST_INTEGRATOR_CP_CM_CORE, /* Only 8 bits of VDW and 3 bits of OD */
+	ICST_INTEGRATOR_CP_CM_MEM, /* Only 8 bits of VDW and 3 bits of OD */
+	ICST_INTEGRATOR_IM_PD1, /* Like the Versatile, all control bits */
+};
+
+/**
+ * struct clk_icst_desc - descriptor for the ICST VCO
+ * @params: ICST parameters
+ * @vco_offset: offset to the ICST VCO from the provided memory base
+ * @lock_offset: offset to the ICST VCO locking register from the provided
+ *	memory base
+ */
+struct clk_icst_desc {
+	const struct icst_params *params;
+	u32 vco_offset;
+	u32 lock_offset;
+};
+
+struct clk *icst_clk_register(struct device *dev,
+			      const struct clk_icst_desc *desc,
+			      const char *name,
+			      const char *parent_name,
+			      void __iomem *base);
+
+struct clk *icst_clk_setup(struct device *dev,
+			   const struct clk_icst_desc *desc,
+			   const char *name,
+			   const char *parent_name,
+			   struct regmap *map,
+			   enum icst_control_type ctype);