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, 75 insertions, 0 deletions

diff --git a/drivers/pmdomain/renesas/rcar-sysc.h b/drivers/pmdomain/renesas/rcar-sysc.h
new file mode 100644
index 000000000..07ffce310
--- /dev/null
+++ b/drivers/pmdomain/renesas/rcar-sysc.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Renesas R-Car System Controller
+ *
+ * Copyright (C) 2016 Glider bvba
+ */
+#ifndef __SOC_RENESAS_RCAR_SYSC_H__
+#define __SOC_RENESAS_RCAR_SYSC_H__
+
+#include <linux/types.h>
+
+
+/*
+ * Power Domain flags
+ */
+#define PD_CPU		BIT(0)	/* Area contains main CPU core */
+#define PD_SCU		BIT(1)	/* Area contains SCU and L2 cache */
+#define PD_NO_CR	BIT(2)	/* Area lacks PWR{ON,OFF}CR registers */
+#define PD_OFF_DELAY	BIT(3)	/* Area is subject to power-off delay quirk */
+
+#define PD_CPU_CR	PD_CPU		  /* CPU area has CR (R-Car H1) */
+#define PD_CPU_NOCR	PD_CPU | PD_NO_CR /* CPU area lacks CR (R-Car Gen2/3) */
+#define PD_ALWAYS_ON	PD_NO_CR	  /* Always-on area */
+
+
+/*
+ * Description of a Power Area
+ */
+
+struct rcar_sysc_area {
+	const char *name;
+	u16 chan_offs;		/* Offset of PWRSR register for this area */
+	u8 chan_bit;		/* Bit in PWR* (except for PWRUP in PWRSR) */
+	u8 isr_bit;		/* Bit in SYSCI*R */
+	s8 parent;		/* -1 if none */
+	u8 flags;		/* See PD_* */
+};
+
+
+/*
+ * SoC-specific Power Area Description
+ */
+
+struct rcar_sysc_info {
+	int (*init)(void);	/* Optional */
+	const struct rcar_sysc_area *areas;
+	unsigned int num_areas;
+	/* Optional External Request Mask Register */
+	u32 extmask_offs;	/* SYSCEXTMASK register offset */
+	u32 extmask_val;	/* SYSCEXTMASK register mask value */
+};
+
+extern const struct rcar_sysc_info r8a7742_sysc_info;
+extern const struct rcar_sysc_info r8a7743_sysc_info;
+extern const struct rcar_sysc_info r8a7745_sysc_info;
+extern const struct rcar_sysc_info r8a77470_sysc_info;
+extern const struct rcar_sysc_info r8a774a1_sysc_info;
+extern const struct rcar_sysc_info r8a774b1_sysc_info;
+extern const struct rcar_sysc_info r8a774c0_sysc_info;
+extern const struct rcar_sysc_info r8a774e1_sysc_info;
+extern const struct rcar_sysc_info r8a7779_sysc_info;
+extern const struct rcar_sysc_info r8a7790_sysc_info;
+extern const struct rcar_sysc_info r8a7791_sysc_info;
+extern const struct rcar_sysc_info r8a7792_sysc_info;
+extern const struct rcar_sysc_info r8a7794_sysc_info;
+extern struct rcar_sysc_info r8a7795_sysc_info;
+extern const struct rcar_sysc_info r8a77960_sysc_info;
+extern const struct rcar_sysc_info r8a77961_sysc_info;
+extern const struct rcar_sysc_info r8a77965_sysc_info;
+extern const struct rcar_sysc_info r8a77970_sysc_info;
+extern const struct rcar_sysc_info r8a77980_sysc_info;
+extern const struct rcar_sysc_info r8a77990_sysc_info;
+extern const struct rcar_sysc_info r8a77995_sysc_info;
+
+#endif /* __SOC_RENESAS_RCAR_SYSC_H__ */