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, 72 insertions, 0 deletions

diff --git a/drivers/scsi/aacraid/nark.c b/drivers/scsi/aacraid/nark.c
new file mode 100644
index 000000000..4745a99fb
--- /dev/null
+++ b/drivers/scsi/aacraid/nark.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Adaptec AAC series RAID controller driver
+ *
+ * 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:
+ *  nark.c
+ *
+ * Abstract: Hardware Device Interface for NEMER/ARK
+ */
+
+#include <linux/pci.h>
+#include <linux/blkdev.h>
+
+#include <scsi/scsi_host.h>
+
+#include "aacraid.h"
+
+/**
+ *	aac_nark_ioremap
+ *	@dev: device to ioremap
+ *	@size: mapping resize request
+ *
+ */
+static int aac_nark_ioremap(struct aac_dev * dev, u32 size)
+{
+	if (!size) {
+		iounmap(dev->regs.rx);
+		dev->regs.rx = NULL;
+		iounmap(dev->base);
+		dev->base = NULL;
+		return 0;
+	}
+	dev->base_start = pci_resource_start(dev->pdev, 2);
+	dev->regs.rx = ioremap((u64)pci_resource_start(dev->pdev, 0) |
+	  ((u64)pci_resource_start(dev->pdev, 1) << 32),
+	  sizeof(struct rx_registers) - sizeof(struct rx_inbound));
+	dev->base = NULL;
+	if (dev->regs.rx == NULL)
+		return -1;
+	dev->base = ioremap(dev->base_start, size);
+	if (dev->base == NULL) {
+		iounmap(dev->regs.rx);
+		dev->regs.rx = NULL;
+		return -1;
+	}
+	dev->IndexRegs = &((struct rx_registers __iomem *)dev->base)->IndexRegs;
+	return 0;
+}
+
+/**
+ *	aac_nark_init	-	initialize an NEMER/ARK Split Bar card
+ *	@dev: device to configure
+ *
+ */
+
+int aac_nark_init(struct aac_dev * dev)
+{
+	/*
+	 *	Fill in the function dispatch table.
+	 */
+	dev->a_ops.adapter_ioremap = aac_nark_ioremap;
+	dev->a_ops.adapter_comm = aac_rx_select_comm;
+
+	return _aac_rx_init(dev);
+}