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, 40 insertions, 0 deletions

diff --git a/arch/arm/mach-spear/generic.h b/arch/arm/mach-spear/generic.h
new file mode 100644
index 000000000..9e36920d4
--- /dev/null
+++ b/arch/arm/mach-spear/generic.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * spear machine family generic header file
+ *
+ * Copyright (C) 2009-2012 ST Microelectronics
+ * Rajeev Kumar <rajeev-dlh.kumar@st.com>
+ * Viresh Kumar <vireshk@kernel.org>
+ */
+
+#ifndef __MACH_GENERIC_H
+#define __MACH_GENERIC_H
+
+#include <linux/dmaengine.h>
+#include <linux/amba/pl08x.h>
+#include <linux/init.h>
+#include <linux/reboot.h>
+
+#include <asm/mach/time.h>
+
+extern volatile int spear_pen_release;
+
+extern void spear13xx_timer_init(void);
+extern void spear3xx_timer_init(void);
+extern struct pl022_ssp_controller pl022_plat_data;
+extern struct pl08x_platform_data pl080_plat_data;
+
+void __init spear_setup_of_timer(void);
+void __init spear3xx_map_io(void);
+void __init spear3xx_dt_init_irq(void);
+void __init spear13xx_map_io(void);
+void __init spear13xx_l2x0_init(void);
+
+void spear_restart(enum reboot_mode, const char *);
+
+void spear13xx_secondary_startup(void);
+void spear13xx_cpu_die(unsigned int cpu);
+
+extern const struct smp_operations spear13xx_smp_ops;
+
+#endif /* __MACH_GENERIC_H */