ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 206 insertions, 0 deletions

diff --git a/drivers/hid/hid-universal-pidff.c b/drivers/hid/hid-universal-pidff.c
new file mode 100644
index 000000000..60180467a
--- /dev/null
+++ b/drivers/hid/hid-universal-pidff.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * HID UNIVERSAL PIDFF
+ * hid-pidff wrapper for PID-enabled devices
+ * Handles device reports, quirks and extends usable button range
+ *
+ * Copyright (c) 2024, 2025 Oleg Makarenko
+ * Copyright (c) 2024, 2025 Tomasz Pakuła
+ */
+
+#include "hid-ids.h"
+#include "usbhid/hid-pidff.h"
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/input-event-codes.h>
+#include <linux/module.h>
+
+#define JOY_RANGE (BTN_DEAD - BTN_JOYSTICK + 1)
+
+/*
+ * Map buttons manually to extend the default joystick button limit
+ */
+static int universal_pidff_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_BUTTON)
+		return 0;
+
+	if (field->application != HID_GD_JOYSTICK)
+		return 0;
+
+	int button = ((usage->hid - 1) & HID_USAGE);
+	int code = button + BTN_JOYSTICK;
+
+	/* Detect the end of JOYSTICK buttons range */
+	if (code > BTN_DEAD)
+		code = button + KEY_NEXT_FAVORITE - JOY_RANGE;
+
+	/*
+	 * Map overflowing buttons to KEY_RESERVED to not ignore
+	 * them and let them still trigger MSC_SCAN
+	 */
+	if (code > KEY_MAX)
+		code = KEY_RESERVED;
+
+	hid_map_usage(hi, usage, bit, max, EV_KEY, code);
+	hid_dbg(hdev, "Button %d: usage %d", button, code);
+	return 1;
+}
+
+/*
+ * Check if the device is PID and initialize it
+ * Add quirks after initialisation
+ */
+static int universal_pidff_probe(struct hid_device *hdev,
+				 const struct hid_device_id *id)
+{
+	int i, error;
+
+	error = hid_parse(hdev);
+	if (error) {
+		hid_err(hdev, "HID parse failed\n");
+		goto err;
+	}
+
+	error = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
+	if (error) {
+		hid_err(hdev, "HID hw start failed\n");
+		goto err;
+	}
+
+	/* Check if device contains PID usage page */
+	error = 1;
+	for (i = 0; i < hdev->collection_size; i++)
+		if ((hdev->collection[i].usage & HID_USAGE_PAGE) == HID_UP_PID) {
+			error = 0;
+			hid_dbg(hdev, "PID usage page found\n");
+			break;
+		}
+
+	/*
+	 * Do not fail as this might be the second "device"
+	 * just for additional buttons/axes. Exit cleanly if force
+	 * feedback usage page wasn't found (included devices were
+	 * tested and confirmed to be USB PID after all).
+	 */
+	if (error) {
+		hid_dbg(hdev, "PID usage page not found in the descriptor\n");
+		return 0;
+	}
+
+	/* Check if HID_PID support is enabled */
+	int (*init_function)(struct hid_device *, u32);
+
+	init_function = hid_pidff_init_with_quirks;
+	if (!init_function) {
+		hid_warn(hdev, "HID_PID support not enabled!\n");
+		return 0;
+	}
+
+	error = init_function(hdev, id->driver_data);
+	if (error) {
+		hid_warn(hdev, "Error initialising force feedback\n");
+		goto err_stop;
+	}
+
+	hid_info(hdev, "Universal pidff driver loaded successfully!");
+
+	return 0;
+err_stop:
+	hid_hw_stop(hdev);
+err:
+	return error;
+}
+
+static int universal_pidff_input_configured(struct hid_device *hdev,
+					    struct hid_input *hidinput)
+{
+	int axis;
+	struct input_dev *input = hidinput->input;
+
+	if (!input->absinfo)
+		return 0;
+
+	/* Decrease fuzz and deadzone on available axes */
+	for (axis = ABS_X; axis <= ABS_BRAKE; axis++) {
+		if (!test_bit(axis, input->absbit))
+			continue;
+
+		input_set_abs_params(input, axis, input->absinfo[axis].minimum,
+				     input->absinfo[axis].maximum,
+				     axis == ABS_X ? 0 : 8, 0);
+	}
+
+	/* Remove fuzz and deadzone from the second joystick axis */
+	if (hdev->vendor == USB_VENDOR_ID_FFBEAST &&
+	    hdev->product == USB_DEVICE_ID_FFBEAST_JOYSTICK)
+		input_set_abs_params(input, ABS_Y,
+				     input->absinfo[ABS_Y].minimum,
+				     input->absinfo[ABS_Y].maximum, 0, 0);
+
+	return 0;
+}
+
+static const struct hid_device_id universal_pidff_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R3),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R3_2),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R5),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R5_2),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R9),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R9_2),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R12),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R12_2),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R16_R21),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MOZA, USB_DEVICE_ID_MOZA_R16_R21_2),
+	  .driver_data = HID_PIDFF_QUIRK_FIX_CONDITIONAL_DIRECTION },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CAMMUS, USB_DEVICE_ID_CAMMUS_C5) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CAMMUS, USB_DEVICE_ID_CAMMUS_C12) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_VRS, USB_DEVICE_ID_VRS_DFP),
+	  .driver_data = HID_PIDFF_QUIRK_PERMISSIVE_CONTROL },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_FFBEAST, USB_DEVICE_ID_FFBEAST_JOYSTICK), },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_FFBEAST, USB_DEVICE_ID_FFBEAST_RUDDER), },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_FFBEAST, USB_DEVICE_ID_FFBEAST_WHEEL) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LITE_STAR, USB_DEVICE_ID_PXN_V10),
+	  .driver_data = HID_PIDFF_QUIRK_PERIODIC_SINE_ONLY },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LITE_STAR, USB_DEVICE_ID_PXN_V12),
+	  .driver_data = HID_PIDFF_QUIRK_PERIODIC_SINE_ONLY },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LITE_STAR, USB_DEVICE_ID_PXN_V12_LITE),
+	  .driver_data = HID_PIDFF_QUIRK_PERIODIC_SINE_ONLY },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LITE_STAR, USB_DEVICE_ID_PXN_V12_LITE_2),
+	  .driver_data = HID_PIDFF_QUIRK_PERIODIC_SINE_ONLY },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LITE_STAR, USB_DEVICE_ID_LITE_STAR_GT987),
+	  .driver_data = HID_PIDFF_QUIRK_PERIODIC_SINE_ONLY },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ASETEK, USB_DEVICE_ID_ASETEK_INVICTA) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ASETEK, USB_DEVICE_ID_ASETEK_FORTE) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ASETEK, USB_DEVICE_ID_ASETEK_LA_PRIMA) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ASETEK, USB_DEVICE_ID_ASETEK_TONY_KANAAN) },
+	{}
+};
+MODULE_DEVICE_TABLE(hid, universal_pidff_devices);
+
+static struct hid_driver universal_pidff = {
+	.name = "hid-universal-pidff",
+	.id_table = universal_pidff_devices,
+	.input_mapping = universal_pidff_input_mapping,
+	.probe = universal_pidff_probe,
+	.input_configured = universal_pidff_input_configured
+};
+module_hid_driver(universal_pidff);
+
+MODULE_DESCRIPTION("Universal driver for USB PID Force Feedback devices");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Oleg Makarenko <oleg@makarenk.ooo>");
+MODULE_AUTHOR("Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>");