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, 48 insertions, 0 deletions

diff --git a/arch/arm/mach-s3c/map-base.h b/arch/arm/mach-s3c/map-base.h
new file mode 100644
index 000000000..beb58e6f1
--- /dev/null
+++ b/arch/arm/mach-s3c/map-base.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2003, 2007 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C - Memory map definitions (virtual addresses)
+ */
+
+#ifndef __ASM_PLAT_MAP_H
+#define __ASM_PLAT_MAP_H __FILE__
+
+/* Fit all our registers in at 0xF6000000 upwards, trying to use as
+ * little of the VA space as possible so vmalloc and friends have a
+ * better chance of getting memory.
+ *
+ * we try to ensure stuff like the IRQ registers are available for
+ * an single MOVS instruction (ie, only 8 bits of set data)
+ */
+
+#define S3C_ADDR_BASE	0xF6000000
+
+#ifndef __ASSEMBLER__
+#define S3C_ADDR(x)	((void __iomem __force *)S3C_ADDR_BASE + (x))
+#else
+#define S3C_ADDR(x)	(S3C_ADDR_BASE + (x))
+#endif
+
+#define S3C_VA_IRQ	S3C_ADDR(0x00000000)	/* irq controller(s) */
+#define S3C_VA_SYS	S3C_ADDR(0x00100000)	/* system control */
+#define S3C_VA_MEM	S3C_ADDR(0x00200000)	/* memory control */
+#define S3C_VA_TIMER	S3C_ADDR(0x00300000)	/* timer block */
+#define S3C_VA_WATCHDOG	S3C_ADDR(0x00400000)	/* watchdog */
+#define S3C_VA_UART	S3C_ADDR(0x01000000)	/* UART */
+
+/* ISA device mapping for BAST to use with inb()/outb() on 8-bit I/O.
+ * 16-bit I/O on BAST now requires driver modifications to manually
+ * ioremap CS3.
+ */
+#define S3C24XX_VA_ISA_BYTE	PCI_IOBASE
+
+/* This is used for the CPU specific mappings that may be needed, so that
+ * they do not need to directly used S3C_ADDR() and thus make it easier to
+ * modify the space for mapping.
+ */
+#define S3C_ADDR_CPU(x)	S3C_ADDR(0x00500000 + (x))
+
+#endif /* __ASM_PLAT_MAP_H */