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, 25 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/mx27.h b/arch/arm/mach-imx/mx27.h
new file mode 100644
index 000000000..241c04d70
--- /dev/null
+++ b/arch/arm/mach-imx/mx27.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ *
+ * This contains i.MX27-specific hardware definitions. For those
+ * hardware pieces that are common between i.MX21 and i.MX27, have a
+ * look at mx2x.h.
+ */
+
+#ifndef __MACH_MX27_H__
+#define __MACH_MX27_H__
+
+#define MX27_AIPI_BASE_ADDR		0x10000000
+#define MX27_AIPI_SIZE			SZ_1M
+
+#define MX27_SAHB1_BASE_ADDR		0x80000000
+#define MX27_SAHB1_SIZE			SZ_1M
+
+#define MX27_X_MEMC_BASE_ADDR		0xd8000000
+#define MX27_X_MEMC_SIZE		SZ_1M
+
+#define MX27_IO_P2V(x)			IMX_IO_P2V(x)
+
+#endif /* ifndef __MACH_MX27_H__ */