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/soc/renesas/rz-sysc.h b/drivers/soc/renesas/rz-sysc.h
new file mode 100644
index 000000000..921ee0d26
--- /dev/null
+++ b/drivers/soc/renesas/rz-sysc.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Renesas RZ System Controller
+ *
+ * Copyright (C) 2024 Renesas Electronics Corp.
+ */
+
+#ifndef __SOC_RENESAS_RZ_SYSC_H__
+#define __SOC_RENESAS_RZ_SYSC_H__
+
+#include <linux/device.h>
+#include <linux/sys_soc.h>
+#include <linux/types.h>
+
+/**
+ * struct rz_syc_soc_id_init_data - RZ SYSC SoC identification initialization data
+ * @family: RZ SoC family
+ * @id: RZ SoC expected ID
+ * @devid_offset: SYSC SoC ID register offset
+ * @revision_mask: SYSC SoC ID revision mask
+ * @specific_id_mask: SYSC SoC ID specific ID mask
+ * @print_id: print SoC-specific extended device identification
+ */
+struct rz_sysc_soc_id_init_data {
+	const char * const family;
+	u32 id;
+	u32 devid_offset;
+	u32 revision_mask;
+	u32 specific_id_mask;
+	void (*print_id)(struct device *dev, void __iomem *sysc_base,
+			 struct soc_device_attribute *soc_dev_attr);
+};
+
+/**
+ * struct rz_sysc_init_data - RZ SYSC initialization data
+ * @soc_id_init_data: RZ SYSC SoC ID initialization data
+ * @writeable_reg: Regmap writeable register check function
+ * @readable_reg: Regmap readable register check function
+ * @max_register: Maximum SYSC register offset to be used by the regmap config
+ */
+struct rz_sysc_init_data {
+	const struct rz_sysc_soc_id_init_data *soc_id_init_data;
+	bool (*writeable_reg)(struct device *dev, unsigned int reg);
+	bool (*readable_reg)(struct device *dev, unsigned int reg);
+	u32 max_register;
+};
+
+extern const struct rz_sysc_init_data rzg3e_sys_init_data;
+extern const struct rz_sysc_init_data rzg3l_sysc_init_data;
+extern const struct rz_sysc_init_data rzg3s_sysc_init_data;
+extern const struct rz_sysc_init_data rzv2h_sys_init_data;
+extern const struct rz_sysc_init_data rzv2n_sys_init_data;
+
+#endif /* __SOC_RENESAS_RZ_SYSC_H__ */