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, 106 insertions, 0 deletions

diff --git a/drivers/hid/hid-petalynx.c b/drivers/hid/hid-petalynx.c
new file mode 100644
index 000000000..1a986f077
--- /dev/null
+++ b/drivers/hid/hid-petalynx.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for some petalynx "special" devices
+ *
+ *  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
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+/* Petalynx Maxter Remote has maximum for consumer page set too low */
+static const __u8 *pl_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize >= 62 && rdesc[39] == 0x2a && rdesc[40] == 0xf5 &&
+			rdesc[41] == 0x00 && rdesc[59] == 0x26 &&
+			rdesc[60] == 0xf9 && rdesc[61] == 0x00) {
+		hid_info(hdev, "fixing up Petalynx Maxter Remote report descriptor\n");
+		rdesc[60] = 0xfa;
+		rdesc[40] = 0xfa;
+	}
+	return rdesc;
+}
+
+#define pl_map_key_clear(c)	hid_map_usage_clear(hi, usage, bit, max, \
+					EV_KEY, (c))
+static int pl_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	if ((usage->hid & HID_USAGE_PAGE) == HID_UP_LOGIVENDOR) {
+		switch (usage->hid & HID_USAGE) {
+		case 0x05a: pl_map_key_clear(KEY_TEXT);		break;
+		case 0x05b: pl_map_key_clear(KEY_RED);		break;
+		case 0x05c: pl_map_key_clear(KEY_GREEN);	break;
+		case 0x05d: pl_map_key_clear(KEY_YELLOW);	break;
+		case 0x05e: pl_map_key_clear(KEY_BLUE);		break;
+		default:
+			return 0;
+		}
+		return 1;
+	}
+
+	if ((usage->hid & HID_USAGE_PAGE) == HID_UP_CONSUMER) {
+		switch (usage->hid & HID_USAGE) {
+		case 0x0f6: pl_map_key_clear(KEY_NEXT);		break;
+		case 0x0fa: pl_map_key_clear(KEY_BACK);		break;
+		default:
+			return 0;
+		}
+		return 1;
+	}
+
+	return 0;
+}
+
+static int pl_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+
+	hdev->quirks |= HID_QUIRK_NOGET;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		goto err_free;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		goto err_free;
+	}
+
+	return 0;
+err_free:
+	return ret;
+}
+
+static const struct hid_device_id pl_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_PETALYNX, USB_DEVICE_ID_PETALYNX_MAXTER_REMOTE) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, pl_devices);
+
+static struct hid_driver pl_driver = {
+	.name = "petalynx",
+	.id_table = pl_devices,
+	.report_fixup = pl_report_fixup,
+	.input_mapping = pl_input_mapping,
+	.probe = pl_probe,
+};
+module_hid_driver(pl_driver);
+
+MODULE_DESCRIPTION("HID driver for some petalynx \"special\" devices");
+MODULE_LICENSE("GPL");