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, 434 insertions, 0 deletions

diff --git a/drivers/usb/serial/upd78f0730.c b/drivers/usb/serial/upd78f0730.c
new file mode 100644
index 000000000..78c4d3c19
--- /dev/null
+++ b/drivers/usb/serial/upd78f0730.c
@@ -0,0 +1,434 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas Electronics uPD78F0730 USB to serial converter driver
+ *
+ * Copyright (C) 2014,2016 Maksim Salau <maksim.salau@gmail.com>
+ *
+ * Protocol of the adaptor is described in the application note U19660EJ1V0AN00
+ * μPD78F0730 8-bit Single-Chip Microcontroller
+ * USB-to-Serial Conversion Software
+ * <https://www.renesas.com/en-eu/doc/DocumentServer/026/U19660EJ1V0AN00.pdf>
+ *
+ * The adaptor functionality is limited to the following:
+ * - data bits: 7 or 8
+ * - stop bits: 1 or 2
+ * - parity: even, odd or none
+ * - flow control: none
+ * - baud rates: 0, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 153600
+ * - signals: DTR, RTS and BREAK
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+#define DRIVER_DESC "Renesas uPD78F0730 USB to serial converter driver"
+
+#define DRIVER_AUTHOR "Maksim Salau <maksim.salau@gmail.com>"
+
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x0409, 0x0063) }, /* V850ESJX3-STICK */
+	{ USB_DEVICE(0x045B, 0x0212) }, /* YRPBRL78G13, YRPBRL78G14 */
+	{ USB_DEVICE(0x064B, 0x7825) }, /* Analog Devices EVAL-ADXL362Z-DB */
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, id_table);
+
+/*
+ * Each adaptor is associated with a private structure, that holds the current
+ * state of control signals (DTR, RTS and BREAK).
+ */
+struct upd78f0730_port_private {
+	struct mutex	lock;		/* mutex to protect line_signals */
+	u8		line_signals;
+};
+
+/* Op-codes of control commands */
+#define UPD78F0730_CMD_LINE_CONTROL	0x00
+#define UPD78F0730_CMD_SET_DTR_RTS	0x01
+#define UPD78F0730_CMD_SET_XON_XOFF_CHR	0x02
+#define UPD78F0730_CMD_OPEN_CLOSE	0x03
+#define UPD78F0730_CMD_SET_ERR_CHR	0x04
+
+/* Data sizes in UPD78F0730_CMD_LINE_CONTROL command */
+#define UPD78F0730_DATA_SIZE_7_BITS	0x00
+#define UPD78F0730_DATA_SIZE_8_BITS	0x01
+#define UPD78F0730_DATA_SIZE_MASK	0x01
+
+/* Stop-bit modes in UPD78F0730_CMD_LINE_CONTROL command */
+#define UPD78F0730_STOP_BIT_1_BIT	0x00
+#define UPD78F0730_STOP_BIT_2_BIT	0x02
+#define UPD78F0730_STOP_BIT_MASK	0x02
+
+/* Parity modes in UPD78F0730_CMD_LINE_CONTROL command */
+#define UPD78F0730_PARITY_NONE	0x00
+#define UPD78F0730_PARITY_EVEN	0x04
+#define UPD78F0730_PARITY_ODD	0x08
+#define UPD78F0730_PARITY_MASK	0x0C
+
+/* Flow control modes in UPD78F0730_CMD_LINE_CONTROL command */
+#define UPD78F0730_FLOW_CONTROL_NONE	0x00
+#define UPD78F0730_FLOW_CONTROL_HW	0x10
+#define UPD78F0730_FLOW_CONTROL_SW	0x20
+#define UPD78F0730_FLOW_CONTROL_MASK	0x30
+
+/* Control signal bits in UPD78F0730_CMD_SET_DTR_RTS command */
+#define UPD78F0730_RTS		0x01
+#define UPD78F0730_DTR		0x02
+#define UPD78F0730_BREAK	0x04
+
+/* Port modes in UPD78F0730_CMD_OPEN_CLOSE command */
+#define UPD78F0730_PORT_CLOSE	0x00
+#define UPD78F0730_PORT_OPEN	0x01
+
+/* Error character substitution modes in UPD78F0730_CMD_SET_ERR_CHR command */
+#define UPD78F0730_ERR_CHR_DISABLED	0x00
+#define UPD78F0730_ERR_CHR_ENABLED	0x01
+
+/*
+ * Declaration of command structures
+ */
+
+/* UPD78F0730_CMD_LINE_CONTROL command */
+struct upd78f0730_line_control {
+	u8	opcode;
+	__le32	baud_rate;
+	u8	params;
+} __packed;
+
+/* UPD78F0730_CMD_SET_DTR_RTS command */
+struct upd78f0730_set_dtr_rts {
+	u8 opcode;
+	u8 params;
+};
+
+/* UPD78F0730_CMD_SET_XON_OFF_CHR command */
+struct upd78f0730_set_xon_xoff_chr {
+	u8 opcode;
+	u8 xon;
+	u8 xoff;
+};
+
+/* UPD78F0730_CMD_OPEN_CLOSE command */
+struct upd78f0730_open_close {
+	u8 opcode;
+	u8 state;
+};
+
+/* UPD78F0730_CMD_SET_ERR_CHR command */
+struct upd78f0730_set_err_chr {
+	u8 opcode;
+	u8 state;
+	u8 err_char;
+};
+
+static int upd78f0730_send_ctl(struct usb_serial_port *port,
+			const void *data, int size)
+{
+	struct usb_device *usbdev = port->serial->dev;
+	void *buf;
+	int res;
+
+	if (size <= 0 || !data)
+		return -EINVAL;
+
+	buf = kmemdup(data, size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	res = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x00,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+			0x0000, 0x0000, buf, size, USB_CTRL_SET_TIMEOUT);
+
+	kfree(buf);
+
+	if (res < 0) {
+		struct device *dev = &port->dev;
+
+		dev_err(dev, "failed to send control request %02x: %d\n",
+			*(u8 *)data, res);
+
+		return res;
+	}
+
+	return 0;
+}
+
+static int upd78f0730_port_probe(struct usb_serial_port *port)
+{
+	struct upd78f0730_port_private *private;
+
+	private = kzalloc_obj(*private);
+	if (!private)
+		return -ENOMEM;
+
+	mutex_init(&private->lock);
+	usb_set_serial_port_data(port, private);
+
+	return 0;
+}
+
+static void upd78f0730_port_remove(struct usb_serial_port *port)
+{
+	struct upd78f0730_port_private *private;
+
+	private = usb_get_serial_port_data(port);
+	mutex_destroy(&private->lock);
+	kfree(private);
+}
+
+static int upd78f0730_tiocmget(struct tty_struct *tty)
+{
+	struct upd78f0730_port_private *private;
+	struct usb_serial_port *port = tty->driver_data;
+	int signals;
+	int res;
+
+	private = usb_get_serial_port_data(port);
+
+	mutex_lock(&private->lock);
+	signals = private->line_signals;
+	mutex_unlock(&private->lock);
+
+	res = ((signals & UPD78F0730_DTR) ? TIOCM_DTR : 0) |
+		((signals & UPD78F0730_RTS) ? TIOCM_RTS : 0);
+
+	dev_dbg(&port->dev, "%s - res = %x\n", __func__, res);
+
+	return res;
+}
+
+static int upd78f0730_tiocmset(struct tty_struct *tty,
+			unsigned int set, unsigned int clear)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct upd78f0730_port_private *private;
+	struct upd78f0730_set_dtr_rts request;
+	struct device *dev = &port->dev;
+	int res;
+
+	private = usb_get_serial_port_data(port);
+
+	mutex_lock(&private->lock);
+	if (set & TIOCM_DTR) {
+		private->line_signals |= UPD78F0730_DTR;
+		dev_dbg(dev, "%s - set DTR\n", __func__);
+	}
+	if (set & TIOCM_RTS) {
+		private->line_signals |= UPD78F0730_RTS;
+		dev_dbg(dev, "%s - set RTS\n", __func__);
+	}
+	if (clear & TIOCM_DTR) {
+		private->line_signals &= ~UPD78F0730_DTR;
+		dev_dbg(dev, "%s - clear DTR\n", __func__);
+	}
+	if (clear & TIOCM_RTS) {
+		private->line_signals &= ~UPD78F0730_RTS;
+		dev_dbg(dev, "%s - clear RTS\n", __func__);
+	}
+	request.opcode = UPD78F0730_CMD_SET_DTR_RTS;
+	request.params = private->line_signals;
+
+	res = upd78f0730_send_ctl(port, &request, sizeof(request));
+	mutex_unlock(&private->lock);
+
+	return res;
+}
+
+static int upd78f0730_break_ctl(struct tty_struct *tty, int break_state)
+{
+	struct upd78f0730_port_private *private;
+	struct usb_serial_port *port = tty->driver_data;
+	struct upd78f0730_set_dtr_rts request;
+	struct device *dev = &port->dev;
+	int res;
+
+	private = usb_get_serial_port_data(port);
+
+	mutex_lock(&private->lock);
+	if (break_state) {
+		private->line_signals |= UPD78F0730_BREAK;
+		dev_dbg(dev, "%s - set BREAK\n", __func__);
+	} else {
+		private->line_signals &= ~UPD78F0730_BREAK;
+		dev_dbg(dev, "%s - clear BREAK\n", __func__);
+	}
+	request.opcode = UPD78F0730_CMD_SET_DTR_RTS;
+	request.params = private->line_signals;
+
+	res = upd78f0730_send_ctl(port, &request, sizeof(request));
+	mutex_unlock(&private->lock);
+
+	return res;
+}
+
+static void upd78f0730_dtr_rts(struct usb_serial_port *port, int on)
+{
+	struct tty_struct *tty = port->port.tty;
+	unsigned int set = 0;
+	unsigned int clear = 0;
+
+	if (on)
+		set = TIOCM_DTR | TIOCM_RTS;
+	else
+		clear = TIOCM_DTR | TIOCM_RTS;
+
+	upd78f0730_tiocmset(tty, set, clear);
+}
+
+static speed_t upd78f0730_get_baud_rate(struct tty_struct *tty)
+{
+	const speed_t baud_rate = tty_get_baud_rate(tty);
+	static const speed_t supported[] = {
+		0, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 153600
+	};
+	int i;
+
+	for (i = ARRAY_SIZE(supported) - 1; i >= 0; i--) {
+		if (baud_rate == supported[i])
+			return baud_rate;
+	}
+
+	/* If the baud rate is not supported, switch to the default one */
+	tty_encode_baud_rate(tty, 9600, 9600);
+
+	return tty_get_baud_rate(tty);
+}
+
+static void upd78f0730_set_termios(struct tty_struct *tty,
+				   struct usb_serial_port *port,
+				   const struct ktermios *old_termios)
+{
+	struct device *dev = &port->dev;
+	struct upd78f0730_line_control request;
+	speed_t baud_rate;
+
+	if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
+		return;
+
+	if (C_BAUD(tty) == B0)
+		upd78f0730_dtr_rts(port, 0);
+	else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
+		upd78f0730_dtr_rts(port, 1);
+
+	baud_rate = upd78f0730_get_baud_rate(tty);
+	request.opcode = UPD78F0730_CMD_LINE_CONTROL;
+	request.baud_rate = cpu_to_le32(baud_rate);
+	request.params = 0;
+	dev_dbg(dev, "%s - baud rate = %d\n", __func__, baud_rate);
+
+	switch (C_CSIZE(tty)) {
+	case CS7:
+		request.params |= UPD78F0730_DATA_SIZE_7_BITS;
+		dev_dbg(dev, "%s - 7 data bits\n", __func__);
+		break;
+	default:
+		tty->termios.c_cflag &= ~CSIZE;
+		tty->termios.c_cflag |= CS8;
+		dev_warn(dev, "data size is not supported, using 8 bits\n");
+		fallthrough;
+	case CS8:
+		request.params |= UPD78F0730_DATA_SIZE_8_BITS;
+		dev_dbg(dev, "%s - 8 data bits\n", __func__);
+		break;
+	}
+
+	if (C_PARENB(tty)) {
+		if (C_PARODD(tty)) {
+			request.params |= UPD78F0730_PARITY_ODD;
+			dev_dbg(dev, "%s - odd parity\n", __func__);
+		} else {
+			request.params |= UPD78F0730_PARITY_EVEN;
+			dev_dbg(dev, "%s - even parity\n", __func__);
+		}
+
+		if (C_CMSPAR(tty)) {
+			tty->termios.c_cflag &= ~CMSPAR;
+			dev_warn(dev, "MARK/SPACE parity is not supported\n");
+		}
+	} else {
+		request.params |= UPD78F0730_PARITY_NONE;
+		dev_dbg(dev, "%s - no parity\n", __func__);
+	}
+
+	if (C_CSTOPB(tty)) {
+		request.params |= UPD78F0730_STOP_BIT_2_BIT;
+		dev_dbg(dev, "%s - 2 stop bits\n", __func__);
+	} else {
+		request.params |= UPD78F0730_STOP_BIT_1_BIT;
+		dev_dbg(dev, "%s - 1 stop bit\n", __func__);
+	}
+
+	if (C_CRTSCTS(tty)) {
+		tty->termios.c_cflag &= ~CRTSCTS;
+		dev_warn(dev, "RTSCTS flow control is not supported\n");
+	}
+	if (I_IXOFF(tty) || I_IXON(tty)) {
+		tty->termios.c_iflag &= ~(IXOFF | IXON);
+		dev_warn(dev, "XON/XOFF flow control is not supported\n");
+	}
+	request.params |= UPD78F0730_FLOW_CONTROL_NONE;
+	dev_dbg(dev, "%s - no flow control\n", __func__);
+
+	upd78f0730_send_ctl(port, &request, sizeof(request));
+}
+
+static int upd78f0730_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	static const struct upd78f0730_open_close request = {
+		.opcode = UPD78F0730_CMD_OPEN_CLOSE,
+		.state = UPD78F0730_PORT_OPEN
+	};
+	int res;
+
+	res = upd78f0730_send_ctl(port, &request, sizeof(request));
+	if (res)
+		return res;
+
+	if (tty)
+		upd78f0730_set_termios(tty, port, NULL);
+
+	return usb_serial_generic_open(tty, port);
+}
+
+static void upd78f0730_close(struct usb_serial_port *port)
+{
+	static const struct upd78f0730_open_close request = {
+		.opcode = UPD78F0730_CMD_OPEN_CLOSE,
+		.state = UPD78F0730_PORT_CLOSE
+	};
+
+	usb_serial_generic_close(port);
+	upd78f0730_send_ctl(port, &request, sizeof(request));
+}
+
+static struct usb_serial_driver upd78f0730_device = {
+	.driver	 = {
+		.name	= "upd78f0730",
+	},
+	.id_table	= id_table,
+	.num_ports	= 1,
+	.port_probe	= upd78f0730_port_probe,
+	.port_remove	= upd78f0730_port_remove,
+	.open		= upd78f0730_open,
+	.close		= upd78f0730_close,
+	.set_termios	= upd78f0730_set_termios,
+	.tiocmget	= upd78f0730_tiocmget,
+	.tiocmset	= upd78f0730_tiocmset,
+	.dtr_rts	= upd78f0730_dtr_rts,
+	.break_ctl	= upd78f0730_break_ctl,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&upd78f0730_device,
+	NULL
+};
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_LICENSE("GPL v2");