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, 57 insertions, 0 deletions

diff --git a/drivers/bcma/scan.h b/drivers/bcma/scan.h
new file mode 100644
index 000000000..e53079a3d
--- /dev/null
+++ b/drivers/bcma/scan.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef BCMA_SCAN_H_
+#define BCMA_SCAN_H_
+
+#define BCMA_ADDR_BASE		0x18000000
+#define BCMA_WRAP_BASE		0x18100000
+
+#define SCAN_ER_VALID		0x00000001
+#define SCAN_ER_TAGX		0x00000006 /* we have to ignore 0x8 bit when checking tag for SCAN_ER_TAG_ADDR */
+#define SCAN_ER_TAG		0x0000000E
+#define  SCAN_ER_TAG_CI		0x00000000
+#define  SCAN_ER_TAG_MP		0x00000002
+#define  SCAN_ER_TAG_ADDR	0x00000004
+#define  SCAN_ER_TAG_END	0x0000000E
+#define SCAN_ER_BAD		0xFFFFFFFF
+
+#define SCAN_CIA_CLASS		0x000000F0
+#define SCAN_CIA_CLASS_SHIFT	4
+#define SCAN_CIA_ID		0x000FFF00
+#define SCAN_CIA_ID_SHIFT	8
+#define SCAN_CIA_MANUF		0xFFF00000
+#define SCAN_CIA_MANUF_SHIFT	20
+
+#define SCAN_CIB_NMP		0x000001F0
+#define SCAN_CIB_NMP_SHIFT	4
+#define SCAN_CIB_NSP		0x00003E00
+#define SCAN_CIB_NSP_SHIFT	9
+#define SCAN_CIB_NMW		0x0007C000
+#define SCAN_CIB_NMW_SHIFT	14
+#define SCAN_CIB_NSW		0x00F80000
+#define SCAN_CIB_NSW_SHIFT	19
+#define SCAN_CIB_REV		0xFF000000
+#define SCAN_CIB_REV_SHIFT	24
+
+#define SCAN_ADDR_AG32		0x00000008
+#define SCAN_ADDR_SZ		0x00000030
+#define SCAN_ADDR_SZ_SHIFT	4
+#define  SCAN_ADDR_SZ_4K	0x00000000
+#define  SCAN_ADDR_SZ_8K	0x00000010
+#define  SCAN_ADDR_SZ_16K	0x00000020
+#define  SCAN_ADDR_SZ_SZD	0x00000030
+#define SCAN_ADDR_TYPE		0x000000C0
+#define  SCAN_ADDR_TYPE_SLAVE	0x00000000
+#define  SCAN_ADDR_TYPE_BRIDGE	0x00000040
+#define  SCAN_ADDR_TYPE_SWRAP	0x00000080
+#define  SCAN_ADDR_TYPE_MWRAP	0x000000C0
+#define SCAN_ADDR_PORT		0x00000F00
+#define SCAN_ADDR_PORT_SHIFT	8
+#define SCAN_ADDR_ADDR		0xFFFFF000
+
+#define SCAN_ADDR_SZ_BASE	0x00001000	/* 4KB */
+
+#define SCAN_SIZE_SZ_ALIGN	0x00000FFF
+#define SCAN_SIZE_SZ		0xFFFFF000
+#define SCAN_SIZE_SG32		0x00000008
+
+#endif /* BCMA_SCAN_H_ */