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, 83 insertions, 0 deletions

diff --git a/drivers/hid/hid-huawei.c b/drivers/hid/hid-huawei.c
new file mode 100644
index 000000000..ee3fc6f68
--- /dev/null
+++ b/drivers/hid/hid-huawei.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  HID driver for some huawei "special" devices
+ *
+ * Copyright (c) 2026 Miao Li <limiao@kylinos.cn>
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+
+static const __u8 huawei_cd30_kbd_rdesc_fixed[] = {
+	0x05, 0x01,		/* Usage Page (Generic Desktop)		*/
+	0x09, 0x80,		/* Usage (System Control)		*/
+	0xa1, 0x01,		/* Collection (Application)		*/
+	0x85, 0x01,		/*   Report ID (1)			*/
+	0x19, 0x81,		/*   Usage Minimum (System Power Down)	*/
+	0x29, 0x83,		/*   Usage Maximum (System Wake Up)	*/
+	0x15, 0x00,		/*   Logical Minimum (0)		*/
+	0x25, 0x01,		/*   Logical Maximum (1)		*/
+	0x75, 0x01,		/*   Report Size (1 bit)		*/
+	0x95, 0x03,		/*   Report Count (3)			*/
+	0x81, 0x02,		/*   Input (Data,Var,Abs)		*/
+	0x95, 0x05,		/*   Report Count (5)			*/
+	0x81, 0x01,		/*   Input (Cnst,Ary,Abs)		*/
+	0xc0,			/* End Collection			*/
+	0x05, 0x0c,		/* Usage Page (Consumer)		*/
+	0x09, 0x01,		/* Usage (Consumer Control)		*/
+	0xa1, 0x01,		/* Collection (Application)		*/
+	0x85, 0x02,		/*   Report ID (2)			*/
+	0x19, 0x00,		/*   Usage Minimum (0)			*/
+	0x2a, 0x3c, 0x02,	/*   Usage Maximum (0x023C)		*/
+	0x15, 0x00,		/*   Logical Minimum (0)		*/
+	0x26, 0x3c, 0x02,	/*   Logical Maximum (0x023C)		*/
+	0x95, 0x01,		/*   Report Count (1)			*/
+	0x75, 0x10,		/*   Report Size (16 bits)		*/
+	0x81, 0x00,		/*   Input (Data,Ary,Abs)		*/
+	0xc0			/* End Collection			*/
+};
+
+static const __u8 *huawei_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+				  unsigned int *rsize)
+{
+	struct usb_interface *intf = hid_is_usb(hdev) ?
+			to_usb_interface(hdev->dev.parent) : NULL;
+
+	switch (hdev->product) {
+	case USB_DEVICE_ID_HUAWEI_CD30KBD:
+		if (!intf || intf->cur_altsetting->desc.bInterfaceNumber == 1) {
+			if (*rsize != sizeof(huawei_cd30_kbd_rdesc_fixed) ||
+				memcmp(huawei_cd30_kbd_rdesc_fixed, rdesc,
+					sizeof(huawei_cd30_kbd_rdesc_fixed)) != 0) {
+				hid_info(hdev, "Replacing Huawei cd30 keyboard report descriptor.\n");
+				*rsize = sizeof(huawei_cd30_kbd_rdesc_fixed);
+				return huawei_cd30_kbd_rdesc_fixed;
+			}
+		}
+		break;
+	}
+
+	return rdesc;
+}
+
+static const struct hid_device_id huawei_devices[] = {
+	/* HUAWEI cd30 keyboard */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_HUAWEI, USB_DEVICE_ID_HUAWEI_CD30KBD)},
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, huawei_devices);
+
+static struct hid_driver huawei_driver = {
+	.name = "huawei",
+	.id_table = huawei_devices,
+	.report_fixup = huawei_report_fixup,
+};
+module_hid_driver(huawei_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Miao Li <limiao@kylinos.cn>");
+MODULE_DESCRIPTION("HID driver for some huawei \"special\" devices");