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/arch/arm/mach-pxa/generic.h b/arch/arm/mach-pxa/generic.h
new file mode 100644
index 000000000..caad4fca8
--- /dev/null
+++ b/arch/arm/mach-pxa/generic.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  linux/arch/arm/mach-pxa/generic.h
+ *
+ * Author:	Nicolas Pitre
+ * Copyright:	MontaVista Software Inc.
+ */
+
+#include <linux/reboot.h>
+
+struct irq_data;
+
+extern void __init pxa_dt_irq_init(int (*fn)(struct irq_data *,
+					     unsigned int));
+extern void __init pxa_map_io(void);
+extern void pxa_timer_init(void);
+
+#define SET_BANK(__nr,__start,__size) \
+	mi->bank[__nr].start = (__start), \
+	mi->bank[__nr].size = (__size)
+
+#define ARRAY_AND_SIZE(x)	(x), ARRAY_SIZE(x)
+
+#define pxa25x_handle_irq icip_handle_irq
+extern void __init pxa25x_init_irq(void);
+extern void __init pxa25x_map_io(void);
+extern void __init pxa26x_init_irq(void);
+
+#define pxa27x_handle_irq ichp_handle_irq
+extern void __init pxa27x_init_irq(void);
+extern void __init pxa27x_map_io(void);
+
+#define pxa3xx_handle_irq ichp_handle_irq
+extern void __init pxa3xx_init_irq(void);
+extern void __init pxa3xx_map_io(void);
+
+extern struct syscore pxa_irq_syscore;
+extern struct syscore pxa2xx_mfp_syscore;
+extern struct syscore pxa3xx_mfp_syscore;
+
+void __init pxa_set_ffuart_info(void *info);
+void __init pxa_set_btuart_info(void *info);
+void __init pxa_set_stuart_info(void *info);
+void __init pxa_set_hwuart_info(void *info);
+
+void pxa_restart(enum reboot_mode, const char *);
+
+#if defined(CONFIG_PXA25x) || defined(CONFIG_PXA27x)
+extern void pxa2xx_clear_reset_status(unsigned int);
+#else
+static inline void pxa2xx_clear_reset_status(unsigned int mask) {}
+#endif
+
+