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, 57 insertions, 0 deletions

diff --git a/drivers/hid/hid-lcpower.c b/drivers/hid/hid-lcpower.c
new file mode 100644
index 000000000..58953d11d
--- /dev/null
+++ b/drivers/hid/hid-lcpower.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for LC Power Model RC1000MCE
+ *
+ *  Copyright (c) 2011 Chris Schlund 
+ *  based on hid-topseed module
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+#define ts_map_key_clear(c)	hid_map_usage_clear(hi, usage, bit, max, \
+					EV_KEY, (c))
+static int ts_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)
+		return 0;
+
+	switch (usage->hid & HID_USAGE) {
+        case 0x046: ts_map_key_clear(KEY_YELLOW);         break;
+        case 0x047: ts_map_key_clear(KEY_GREEN);          break;
+        case 0x049: ts_map_key_clear(KEY_BLUE);           break;
+        case 0x04a: ts_map_key_clear(KEY_RED);		  break;
+        case 0x00d: ts_map_key_clear(KEY_HOME);           break;
+        case 0x025: ts_map_key_clear(KEY_TV);             break;
+        case 0x048: ts_map_key_clear(KEY_VCR);            break;
+        case 0x024: ts_map_key_clear(KEY_MENU);           break;
+        default:
+        return 0;
+	}
+
+	return 1;
+}
+
+static const struct hid_device_id ts_devices[] = {
+	{ HID_USB_DEVICE( USB_VENDOR_ID_LCPOWER, USB_DEVICE_ID_LCPOWER_LC1000) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ts_devices);
+
+static struct hid_driver ts_driver = {
+	.name = "LC RC1000MCE",
+	.id_table = ts_devices,
+	.input_mapping = ts_input_mapping,
+};
+module_hid_driver(ts_driver);
+
+MODULE_DESCRIPTION("HID driver for LC Power Model RC1000MCE");
+MODULE_LICENSE("GPL");