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, 41 insertions, 0 deletions

diff --git a/drivers/hid/usbhid/hid-pidff.h b/drivers/hid/usbhid/hid-pidff.h
new file mode 100644
index 000000000..c413aa732
--- /dev/null
+++ b/drivers/hid/usbhid/hid-pidff.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __HID_PIDFF_H
+#define __HID_PIDFF_H
+
+#include <linux/hid.h>
+
+/* HID PIDFF quirks */
+
+/* Delay field (0xA7) missing. Skip it during set effect report upload */
+#define HID_PIDFF_QUIRK_MISSING_DELAY		BIT(0)
+
+/* Missing Paramter block offset (0x23). Skip it during SET_CONDITION upload */
+#define HID_PIDFF_QUIRK_MISSING_PBO		BIT(1)
+
+/* Initialise device control field even if logical_minimum != 1 */
+#define HID_PIDFF_QUIRK_PERMISSIVE_CONTROL	BIT(2)
+
+/* Use fixed 0x4000 direction during SET_EFFECT report upload */
+#define HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION	BIT(3)
+
+/* Force all periodic effects to be uploaded as SINE */
+#define HID_PIDFF_QUIRK_PERIODIC_SINE_ONLY	BIT(4)
+
+/* Allow devices with missing negative coefficient in the set condition usage */
+#define HID_PIDFF_QUIRK_MISSING_NEG_COEFFICIENT	BIT(5)
+
+/* Allow devices with missing negative saturation in the set condition usage */
+#define HID_PIDFF_QUIRK_MISSING_NEG_SATURATION	BIT(6)
+
+/* Allow devices with missing deadband in the set condition usage */
+#define HID_PIDFF_QUIRK_MISSING_DEADBAND	BIT(7)
+
+#ifdef CONFIG_HID_PID
+int hid_pidff_init(struct hid_device *hid);
+int hid_pidff_init_with_quirks(struct hid_device *hid, u32 initial_quirks);
+#else
+#define hid_pidff_init NULL
+#define hid_pidff_init_with_quirks NULL
+#endif
+
+#endif