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, 53 insertions, 0 deletions

diff --git a/drivers/scsi/gvp11.h b/drivers/scsi/gvp11.h
new file mode 100644
index 000000000..61c1a3584
--- /dev/null
+++ b/drivers/scsi/gvp11.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef GVP11_H
+
+/* $Id: gvp11.h,v 1.4 1997/01/19 23:07:12 davem Exp $
+ *
+ * Header file for the GVP Series II SCSI controller for Linux
+ *
+ * Written and (C) 1993, Ralf Baechle, see gvp11.c for more info
+ * based on a2091.h (C) 1993 by Hamish Macdonald
+ *
+ */
+
+#include <linux/types.h>
+
+#ifndef CMD_PER_LUN
+#define CMD_PER_LUN		2
+#endif
+
+#ifndef CAN_QUEUE
+#define CAN_QUEUE		16
+#endif
+
+/*
+ * if the transfer address ANDed with this results in a non-zero
+ * result, then we can't use DMA.
+ */
+#define GVP11_XFER_MASK		(0xff000001)
+
+struct gvp11_scsiregs {
+		 unsigned char	pad1[64];
+	volatile unsigned short	CNTR;
+		 unsigned char	pad2[31];
+	volatile unsigned char	SASR;
+		 unsigned char	pad3;
+	volatile unsigned char	SCMD;
+		 unsigned char	pad4[4];
+	volatile unsigned short	BANK;
+		 unsigned char	pad5[6];
+	volatile unsigned long	ACR;
+	volatile unsigned short	secret1; /* store 0 here */
+	volatile unsigned short	ST_DMA;
+	volatile unsigned short	SP_DMA;
+	volatile unsigned short	secret2; /* store 1 here */
+	volatile unsigned short	secret3; /* store 15 here */
+};
+
+/* bits in CNTR */
+#define GVP11_DMAC_BUSY		(1<<0)
+#define GVP11_DMAC_INT_PENDING	(1<<1)
+#define GVP11_DMAC_INT_ENABLE	(1<<3)
+#define GVP11_DMAC_DIR_WRITE	(1<<4)
+
+#endif /* GVP11_H */