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, 56 insertions, 0 deletions

diff --git a/drivers/hid/hid-nti.c b/drivers/hid/hid-nti.c
new file mode 100644
index 000000000..03f7dd491
--- /dev/null
+++ b/drivers/hid/hid-nti.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  USB HID quirks support for Network Technologies, Inc. "USB-SUN" USB
+ *  adapter for pre-USB Sun keyboards
+ *
+ *  Copyright (c) 2011 Google, Inc.
+ *
+ * Based on HID apple driver by
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2006-2007 Jiri Kosina
+ *  Copyright (c) 2008 Jiri Slaby <jirislaby@gmail.com>
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+MODULE_AUTHOR("Jonathan Klabunde Tomer <jktomer@google.com>");
+MODULE_DESCRIPTION("HID driver for Network Technologies USB-SUN keyboard adapter");
+
+/*
+ * NTI Sun keyboard adapter has wrong logical maximum in report descriptor
+ */
+static const __u8 *nti_usbsun_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize >= 60 && rdesc[53] == 0x65 && rdesc[59] == 0x65) {
+		hid_info(hdev, "fixing up NTI USB-SUN keyboard adapter report descriptor\n");
+		rdesc[53] = rdesc[59] = 0xe7;
+	}
+	return rdesc;
+}
+
+static const struct hid_device_id nti_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTI, USB_DEVICE_ID_USB_SUN) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, nti_devices);
+
+static struct hid_driver nti_driver = {
+	.name = "nti",
+	.id_table = nti_devices,
+	.report_fixup = nti_usbsun_report_fixup
+};
+
+module_hid_driver(nti_driver);
+
+MODULE_LICENSE("GPL");