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, 175 insertions, 0 deletions

diff --git a/drivers/hid/hid-roccat-common.c b/drivers/hid/hid-roccat-common.c
new file mode 100644
index 000000000..4465ef95d
--- /dev/null
+++ b/drivers/hid/hid-roccat-common.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Roccat common functions for device specific drivers
+ *
+ * Copyright (c) 2011 Stefan Achatz <erazor_de@users.sourceforge.net>
+ */
+
+/*
+ */
+
+#include <linux/hid.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include "hid-roccat-common.h"
+
+static inline uint16_t roccat_common2_feature_report(uint8_t report_id)
+{
+	return 0x300 | report_id;
+}
+
+int roccat_common2_receive(struct usb_device *usb_dev, uint report_id,
+		void *data, uint size)
+{
+	char *buf;
+	int len;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	len = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
+			HID_REQ_GET_REPORT,
+			USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			roccat_common2_feature_report(report_id),
+			0, buf, size, USB_CTRL_SET_TIMEOUT);
+
+	memcpy(data, buf, size);
+	kfree(buf);
+	return ((len < 0) ? len : ((len != size) ? -EIO : 0));
+}
+EXPORT_SYMBOL_GPL(roccat_common2_receive);
+
+int roccat_common2_send(struct usb_device *usb_dev, uint report_id,
+		void const *data, uint size)
+{
+	char *buf;
+	int len;
+
+	buf = kmemdup(data, size, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	len = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
+			HID_REQ_SET_REPORT,
+			USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
+			roccat_common2_feature_report(report_id),
+			0, buf, size, USB_CTRL_SET_TIMEOUT);
+
+	kfree(buf);
+	return ((len < 0) ? len : ((len != size) ? -EIO : 0));
+}
+EXPORT_SYMBOL_GPL(roccat_common2_send);
+
+enum roccat_common2_control_states {
+	ROCCAT_COMMON_CONTROL_STATUS_CRITICAL = 0,
+	ROCCAT_COMMON_CONTROL_STATUS_OK = 1,
+	ROCCAT_COMMON_CONTROL_STATUS_INVALID = 2,
+	ROCCAT_COMMON_CONTROL_STATUS_BUSY = 3,
+	ROCCAT_COMMON_CONTROL_STATUS_CRITICAL_NEW = 4,
+};
+
+static int roccat_common2_receive_control_status(struct usb_device *usb_dev)
+{
+	int retval;
+	struct roccat_common2_control control;
+
+	do {
+		msleep(50);
+		retval = roccat_common2_receive(usb_dev,
+				ROCCAT_COMMON_COMMAND_CONTROL,
+				&control, sizeof(struct roccat_common2_control));
+
+		if (retval)
+			return retval;
+
+		switch (control.value) {
+		case ROCCAT_COMMON_CONTROL_STATUS_OK:
+			return 0;
+		case ROCCAT_COMMON_CONTROL_STATUS_BUSY:
+			msleep(500);
+			continue;
+		case ROCCAT_COMMON_CONTROL_STATUS_INVALID:
+		case ROCCAT_COMMON_CONTROL_STATUS_CRITICAL:
+		case ROCCAT_COMMON_CONTROL_STATUS_CRITICAL_NEW:
+			return -EINVAL;
+		default:
+			dev_err(&usb_dev->dev,
+					"roccat_common2_receive_control_status: "
+					"unknown response value 0x%x\n",
+					control.value);
+			return -EINVAL;
+		}
+
+	} while (1);
+}
+
+int roccat_common2_send_with_status(struct usb_device *usb_dev,
+		uint command, void const *buf, uint size)
+{
+	int retval;
+
+	retval = roccat_common2_send(usb_dev, command, buf, size);
+	if (retval)
+		return retval;
+
+	msleep(100);
+
+	return roccat_common2_receive_control_status(usb_dev);
+}
+EXPORT_SYMBOL_GPL(roccat_common2_send_with_status);
+
+int roccat_common2_device_init_struct(struct usb_device *usb_dev,
+		struct roccat_common2_device *dev)
+{
+	mutex_init(&dev->lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(roccat_common2_device_init_struct);
+
+ssize_t roccat_common2_sysfs_read(struct file *fp, struct kobject *kobj,
+		char *buf, loff_t off, size_t count,
+		size_t real_size, uint command)
+{
+	struct device *dev = kobj_to_dev(kobj)->parent->parent;
+	struct roccat_common2_device *roccat_dev = hid_get_drvdata(dev_get_drvdata(dev));
+	struct usb_device *usb_dev = interface_to_usbdev(to_usb_interface(dev));
+	int retval;
+
+	if (off >= real_size)
+		return 0;
+
+	if (off != 0 || count != real_size)
+		return -EINVAL;
+
+	mutex_lock(&roccat_dev->lock);
+	retval = roccat_common2_receive(usb_dev, command, buf, real_size);
+	mutex_unlock(&roccat_dev->lock);
+
+	return retval ? retval : real_size;
+}
+EXPORT_SYMBOL_GPL(roccat_common2_sysfs_read);
+
+ssize_t roccat_common2_sysfs_write(struct file *fp, struct kobject *kobj,
+		void const *buf, loff_t off, size_t count,
+		size_t real_size, uint command)
+{
+	struct device *dev = kobj_to_dev(kobj)->parent->parent;
+	struct roccat_common2_device *roccat_dev = hid_get_drvdata(dev_get_drvdata(dev));
+	struct usb_device *usb_dev = interface_to_usbdev(to_usb_interface(dev));
+	int retval;
+
+	if (off != 0 || count != real_size)
+		return -EINVAL;
+
+	mutex_lock(&roccat_dev->lock);
+	retval = roccat_common2_send_with_status(usb_dev, command, buf, real_size);
+	mutex_unlock(&roccat_dev->lock);
+
+	return retval ? retval : real_size;
+}
+EXPORT_SYMBOL_GPL(roccat_common2_sysfs_write);
+
+MODULE_AUTHOR("Stefan Achatz");
+MODULE_DESCRIPTION("USB Roccat common driver");
+MODULE_LICENSE("GPL v2");