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, 192 insertions, 0 deletions

diff --git a/drivers/hid/hid-cypress.c b/drivers/hid/hid-cypress.c
new file mode 100644
index 000000000..f18fddc17
--- /dev/null
+++ b/drivers/hid/hid-cypress.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for some cypress "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/input.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+#define CP_RDESC_SWAPPED_MIN_MAX	0x01
+#define CP_2WHEEL_MOUSE_HACK		0x02
+#define CP_2WHEEL_MOUSE_HACK_ON		0x04
+
+#define VA_INVAL_LOGICAL_BOUNDARY	0x08
+
+struct cp_device {
+	unsigned long quirks;
+};
+
+/*
+ * Some USB barcode readers from cypress have usage min and usage max in
+ * the wrong order
+ */
+static __u8 *cp_rdesc_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	unsigned int i;
+
+	if (*rsize < 4)
+		return rdesc;
+
+	for (i = 0; i < *rsize - 4; i++)
+		if (rdesc[i] == 0x29 && rdesc[i + 2] == 0x19) {
+			rdesc[i] = 0x19;
+			rdesc[i + 2] = 0x29;
+			swap(rdesc[i + 3], rdesc[i + 1]);
+		}
+	return rdesc;
+}
+
+static __u8 *va_logical_boundary_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	/*
+	 * Varmilo VA104M (with VID Cypress and device ID 07B1) incorrectly
+	 * reports Logical Minimum of its Consumer Control device as 572
+	 * (0x02 0x3c). Fix this by setting its Logical Minimum to zero.
+	 */
+	if (*rsize == 25 &&
+			rdesc[0] == 0x05 && rdesc[1] == 0x0c &&
+			rdesc[2] == 0x09 && rdesc[3] == 0x01 &&
+			rdesc[6] == 0x19 && rdesc[7] == 0x00 &&
+			rdesc[11] == 0x16 && rdesc[12] == 0x3c && rdesc[13] == 0x02) {
+		hid_info(hdev,
+			 "fixing up varmilo VA104M consumer control report descriptor\n");
+		rdesc[12] = 0x00;
+		rdesc[13] = 0x00;
+	}
+	return rdesc;
+}
+
+static const __u8 *cp_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	const struct cp_device *cp_device = hid_get_drvdata(hdev);
+	unsigned long quirks = cp_device->quirks;
+
+	if (quirks & CP_RDESC_SWAPPED_MIN_MAX)
+		rdesc = cp_rdesc_fixup(hdev, rdesc, rsize);
+	if (quirks & VA_INVAL_LOGICAL_BOUNDARY)
+		rdesc = va_logical_boundary_fixup(hdev, rdesc, rsize);
+
+	return rdesc;
+}
+
+static int cp_input_mapped(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	const struct cp_device *cp_device = hid_get_drvdata(hdev);
+	unsigned long quirks = cp_device->quirks;
+
+	if (!(quirks & CP_2WHEEL_MOUSE_HACK))
+		return 0;
+
+	if (usage->type == EV_REL && usage->code == REL_WHEEL)
+		set_bit(REL_HWHEEL, *bit);
+	if (usage->hid == 0x00090005)
+		return -1;
+
+	return 0;
+}
+
+static int cp_event(struct hid_device *hdev, struct hid_field *field,
+		struct hid_usage *usage, __s32 value)
+{
+	struct cp_device *cp_device = hid_get_drvdata(hdev);
+
+	if (!(hdev->claimed & HID_CLAIMED_INPUT) || !field->hidinput ||
+			!usage->type || !(cp_device->quirks & CP_2WHEEL_MOUSE_HACK))
+		return 0;
+
+	if (usage->hid == 0x00090005) {
+		if (value)
+			cp_device->quirks |= CP_2WHEEL_MOUSE_HACK_ON;
+		else
+			cp_device->quirks &= ~CP_2WHEEL_MOUSE_HACK_ON;
+		return 1;
+	}
+
+	if (usage->code == REL_WHEEL && (cp_device->quirks & CP_2WHEEL_MOUSE_HACK_ON)) {
+		struct input_dev *input = field->hidinput->input;
+
+		input_event(input, usage->type, REL_HWHEEL, value);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int cp_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+	struct cp_device *cp_device;
+
+	cp_device = devm_kzalloc(&hdev->dev, sizeof(*cp_device), GFP_KERNEL);
+
+	if (!cp_device)
+		return -ENOMEM;
+
+	cp_device->quirks = id->driver_data;
+
+	hid_set_drvdata(hdev, cp_device);
+
+	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 cp_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_1),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_2),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_3),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_4),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_MOUSE),
+		.driver_data = CP_2WHEEL_MOUSE_HACK },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_VARMILO_VA104M_07B1),
+		.driver_data = VA_INVAL_LOGICAL_BOUNDARY },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, cp_devices);
+
+static struct hid_driver cp_driver = {
+	.name = "cypress",
+	.id_table = cp_devices,
+	.report_fixup = cp_report_fixup,
+	.input_mapped = cp_input_mapped,
+	.event = cp_event,
+	.probe = cp_probe,
+};
+module_hid_driver(cp_driver);
+
+MODULE_DESCRIPTION("HID driver for some cypress \"special\" devices");
+MODULE_LICENSE("GPL");