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, 95 insertions, 0 deletions

diff --git a/drivers/scsi/aacraid/rkt.c b/drivers/scsi/aacraid/rkt.c
new file mode 100644
index 000000000..8ebc67e54
--- /dev/null
+++ b/drivers/scsi/aacraid/rkt.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Adaptec AAC series RAID controller driver
+ *	(c) Copyright 2001 Red Hat Inc.
+ *
+ * based on the old aacraid driver that is..
+ * Adaptec aacraid device driver for Linux.
+ *
+ * Copyright (c) 2000-2010 Adaptec, Inc.
+ *               2010-2015 PMC-Sierra, Inc. (aacraid@pmc-sierra.com)
+ *		 2016-2017 Microsemi Corp. (aacraid@microsemi.com)
+ *
+ * Module Name:
+ *  rkt.c
+ *
+ * Abstract: Hardware miniport for Drawbridge specific hardware functions.
+ */
+
+#include <linux/blkdev.h>
+
+#include <scsi/scsi_host.h>
+
+#include "aacraid.h"
+
+#define AAC_NUM_IO_FIB_RKT      (246 - AAC_NUM_MGT_FIB)
+
+/**
+ *	aac_rkt_select_comm	-	Select communications method
+ *	@dev: Adapter
+ *	@comm: communications method
+ */
+
+static int aac_rkt_select_comm(struct aac_dev *dev, int comm)
+{
+	int retval;
+	retval = aac_rx_select_comm(dev, comm);
+	if (comm == AAC_COMM_MESSAGE) {
+		/*
+		 * FIB Setup has already been done, but we can minimize the
+		 * damage by at least ensuring the OS never issues more
+		 * commands than we can handle. The Rocket adapters currently
+		 * can only handle 246 commands and 8 AIFs at the same time,
+		 * and in fact do notify us accordingly if we negotiate the
+		 * FIB size. The problem that causes us to add this check is
+		 * to ensure that we do not overdo it with the adapter when a
+		 * hard coded FIB override is being utilized. This special
+		 * case warrants this half baked, but convenient, check here.
+		 */
+		if (dev->scsi_host_ptr->can_queue > AAC_NUM_IO_FIB_RKT) {
+			dev->init->r7.max_io_commands =
+				cpu_to_le32(AAC_NUM_IO_FIB_RKT + AAC_NUM_MGT_FIB);
+			dev->scsi_host_ptr->can_queue = AAC_NUM_IO_FIB_RKT;
+		}
+	}
+	return retval;
+}
+
+/**
+ *	aac_rkt_ioremap
+ *	@dev: device to ioremap
+ *	@size: mapping resize request
+ *
+ */
+static int aac_rkt_ioremap(struct aac_dev * dev, u32 size)
+{
+	if (!size) {
+		iounmap(dev->regs.rkt);
+		return 0;
+	}
+	dev->base = dev->regs.rkt = ioremap(dev->base_start, size);
+	if (dev->base == NULL)
+		return -1;
+	dev->IndexRegs = &dev->regs.rkt->IndexRegs;
+	return 0;
+}
+
+/**
+ *	aac_rkt_init	-	initialize an i960 based AAC card
+ *	@dev: device to configure
+ *
+ *	Allocate and set up resources for the i960 based AAC variants. The
+ *	device_interface in the commregion will be allocated and linked
+ *	to the comm region.
+ */
+
+int aac_rkt_init(struct aac_dev *dev)
+{
+	/*
+	 *	Fill in the function dispatch table.
+	 */
+	dev->a_ops.adapter_ioremap = aac_rkt_ioremap;
+	dev->a_ops.adapter_comm = aac_rkt_select_comm;
+
+	return _aac_rx_init(dev);
+}