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USB: serial: mos7840: fix probe error handling 

The driver would return success and leave the port structures
half-initialised if any of the register accesses during probe fails.

This would specifically leave the port control urb unallocated,
something which could trigger a NULL pointer dereference on interrupt
events.

Fortunately the interrupt implementation is completely broken and has
never even been enabled...

Note that the zero-length-enable register write used to set the zle-flag
for all ports is moved to attach.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2019-11-07 14:28:56 +01:00
parent 1c333550ea
commit 960fbd1ca5
1 changed files with 28 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/usb/serial/mos7840.c
View File

@ -2066,6 +2066,23 @@ static int mos7840_calc_num_ports(struct usb_serial *serial,
return num_ports;
}
static int mos7840_attach(struct usb_serial *serial)
{
struct device *dev = &serial->interface->dev;
int status;
u16 val;
/* Zero Length flag enable */
val = 0x0f;
status = mos7840_set_reg_sync(serial->port[0], ZLP_REG5, val);
if (status < 0)
dev_dbg(dev, "Writing ZLP_REG5 failed status-0x%x\n", status);
else
dev_dbg(dev, "ZLP_REG5 Writing success status%d\n", status);
return status;
}
static int mos7840_port_probe(struct usb_serial_port *port)
{
struct usb_serial *serial = port->serial;
@ -2123,7 +2140,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
mos7840_port->ControlRegOffset, &Data);
if (status < 0) {
dev_dbg(&port->dev, "Reading ControlReg failed status-0x%x\n", status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "ControlReg Reading success val is %x, status%d\n", Data, status);
Data |= 0x08; /* setting driver done bit */
@ -2135,7 +2152,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
mos7840_port->ControlRegOffset, Data);
if (status < 0) {
dev_dbg(&port->dev, "Writing ControlReg failed(rx_disable) status-0x%x\n", status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "ControlReg Writing success(rx_disable) status%d\n", status);
@ -2146,7 +2163,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
(__u16) (mos7840_port->DcrRegOffset + 0), Data);
if (status < 0) {
dev_dbg(&port->dev, "Writing DCR0 failed status-0x%x\n", status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "DCR0 Writing success status%d\n", status);
@ -2155,7 +2172,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
(__u16) (mos7840_port->DcrRegOffset + 1), Data);
if (status < 0) {
dev_dbg(&port->dev, "Writing DCR1 failed status-0x%x\n", status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "DCR1 Writing success status%d\n", status);
@ -2164,7 +2181,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
(__u16) (mos7840_port->DcrRegOffset + 2), Data);
if (status < 0) {
dev_dbg(&port->dev, "Writing DCR2 failed status-0x%x\n", status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "DCR2 Writing success status%d\n", status);
@ -2173,7 +2190,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
status = mos7840_set_reg_sync(port, CLK_START_VALUE_REGISTER, Data);
if (status < 0) {
dev_dbg(&port->dev, "Writing CLK_START_VALUE_REGISTER failed status-0x%x\n", status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "CLK_START_VALUE_REGISTER Writing success status%d\n", status);
@ -2190,7 +2207,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
status = mos7840_set_uart_reg(port, SCRATCH_PAD_REGISTER, Data);
if (status < 0) {
dev_dbg(&port->dev, "Writing SCRATCH_PAD_REGISTER failed status-0x%x\n", status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "SCRATCH_PAD_REGISTER Writing success status%d\n", status);
@ -2204,7 +2221,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
(__u16)(ZLP_REG1 + ((__u16) mos7840_port->port_num)));
if (status < 0) {
dev_dbg(&port->dev, "Writing ZLP_REG%d failed status-0x%x\n", pnum + 2, status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "ZLP_REG%d Writing success status%d\n", pnum + 2, status);
} else {
@ -2216,7 +2233,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
(__u16)(ZLP_REG1 + ((__u16) mos7840_port->port_num) - 0x1));
if (status < 0) {
dev_dbg(&port->dev, "Writing ZLP_REG%d failed status-0x%x\n", pnum + 1, status);
goto out;
goto error;
} else
dev_dbg(&port->dev, "ZLP_REG%d Writing success status%d\n", pnum + 1, status);
@ -2254,17 +2271,7 @@ static int mos7840_port_probe(struct usb_serial_port *port)
/* Turn off LED */
mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0300);
}
out:
if (pnum == serial->num_ports - 1) {
/* Zero Length flag enable */
Data = 0x0f;
status = mos7840_set_reg_sync(serial->port[0], ZLP_REG5, Data);
if (status < 0) {
dev_dbg(&port->dev, "Writing ZLP_REG5 failed status-0x%x\n", status);
goto error;
} else
dev_dbg(&port->dev, "ZLP_REG5 Writing success status%d\n", status);
}
return 0;
error:
kfree(mos7840_port->led_dr);
@ -2320,6 +2327,7 @@ static struct usb_serial_driver moschip7840_4port_device = {
.unthrottle = mos7840_unthrottle,
.calc_num_ports = mos7840_calc_num_ports,
.probe = mos7840_probe,
.attach = mos7840_attach,
.ioctl = mos7840_ioctl,
.get_serial = mos7840_get_serial_info,
.set_termios = mos7840_set_termios,