USB: mos7840: fix race in led handling
Fix race in LED handling introduced by commit 0eafe4de ("USB: serial:
mos7840: add support for MCS7810 devices") which reused the port control
urb for manipulating the LED without making sure that the urb is not
already in use. This could lead to the control urb being manipulated
while in flight.
Fix by adding a dedicated LED urb and ctrlrequest along with a LED-busy
flag to handle concurrency.
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index e95d914..c10fc15 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -185,6 +185,7 @@
enum mos7840_flag {
MOS7840_FLAG_CTRL_BUSY,
+ MOS7840_FLAG_LED_BUSY,
};
static const struct usb_device_id id_table[] = {
@@ -240,9 +241,10 @@
/* For device(s) with LED indicator */
bool has_led;
- bool led_flag;
struct timer_list led_timer1; /* Timer for LED on */
struct timer_list led_timer2; /* Timer for LED off */
+ struct urb *led_urb;
+ struct usb_ctrlrequest *led_dr;
unsigned long flags;
};
@@ -535,7 +537,7 @@
__u16 reg)
{
struct usb_device *dev = mcs->port->serial->dev;
- struct usb_ctrlrequest *dr = mcs->dr;
+ struct usb_ctrlrequest *dr = mcs->led_dr;
dr->bRequestType = MCS_WR_RTYPE;
dr->bRequest = MCS_WRREQ;
@@ -543,10 +545,10 @@
dr->wIndex = cpu_to_le16(reg);
dr->wLength = cpu_to_le16(0);
- usb_fill_control_urb(mcs->control_urb, dev, usb_sndctrlpipe(dev, 0),
+ usb_fill_control_urb(mcs->led_urb, dev, usb_sndctrlpipe(dev, 0),
(unsigned char *)dr, NULL, 0, mos7840_set_led_callback, NULL);
- usb_submit_urb(mcs->control_urb, GFP_ATOMIC);
+ usb_submit_urb(mcs->led_urb, GFP_ATOMIC);
}
static void mos7840_set_led_sync(struct usb_serial_port *port, __u16 reg,
@@ -572,7 +574,19 @@
{
struct moschip_port *mcs = (struct moschip_port *) arg;
- mcs->led_flag = false;
+ clear_bit_unlock(MOS7840_FLAG_LED_BUSY, &mcs->flags);
+}
+
+static void mos7840_led_activity(struct usb_serial_port *port)
+{
+ struct moschip_port *mos7840_port = usb_get_serial_port_data(port);
+
+ if (test_and_set_bit_lock(MOS7840_FLAG_LED_BUSY, &mos7840_port->flags))
+ return;
+
+ mos7840_set_led_async(mos7840_port, 0x0301, MODEM_CONTROL_REGISTER);
+ mod_timer(&mos7840_port->led_timer1,
+ jiffies + msecs_to_jiffies(LED_ON_MS));
}
/*****************************************************************************
@@ -770,14 +784,8 @@
return;
}
- /* Turn on LED */
- if (mos7840_port->has_led && !mos7840_port->led_flag) {
- mos7840_port->led_flag = true;
- mos7840_set_led_async(mos7840_port, 0x0301,
- MODEM_CONTROL_REGISTER);
- mod_timer(&mos7840_port->led_timer1,
- jiffies + msecs_to_jiffies(LED_ON_MS));
- }
+ if (mos7840_port->has_led)
+ mos7840_led_activity(port);
mos7840_port->read_urb_busy = true;
retval = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
@@ -1454,13 +1462,8 @@
data1 = urb->transfer_buffer;
dev_dbg(&port->dev, "bulkout endpoint is %d\n", port->bulk_out_endpointAddress);
- /* Turn on LED */
- if (mos7840_port->has_led && !mos7840_port->led_flag) {
- mos7840_port->led_flag = true;
- mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0301);
- mod_timer(&mos7840_port->led_timer1,
- jiffies + msecs_to_jiffies(LED_ON_MS));
- }
+ if (mos7840_port->has_led)
+ mos7840_led_activity(port);
/* send it down the pipe */
status = usb_submit_urb(urb, GFP_ATOMIC);
@@ -2412,6 +2415,14 @@
if (device_type == MOSCHIP_DEVICE_ID_7810) {
mos7840_port->has_led = true;
+ mos7840_port->led_urb = usb_alloc_urb(0, GFP_KERNEL);
+ mos7840_port->led_dr = kmalloc(sizeof(*mos7840_port->led_dr),
+ GFP_KERNEL);
+ if (!mos7840_port->led_urb || !mos7840_port->led_dr) {
+ status = -ENOMEM;
+ goto error;
+ }
+
init_timer(&mos7840_port->led_timer1);
mos7840_port->led_timer1.function = mos7840_led_off;
mos7840_port->led_timer1.expires =
@@ -2424,8 +2435,6 @@
jiffies + msecs_to_jiffies(LED_OFF_MS);
mos7840_port->led_timer2.data = (unsigned long)mos7840_port;
- mos7840_port->led_flag = false;
-
/* Turn off LED */
mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0300);
}
@@ -2447,6 +2456,8 @@
}
return 0;
error:
+ kfree(mos7840_port->led_dr);
+ usb_free_urb(mos7840_port->led_urb);
kfree(mos7840_port->dr);
kfree(mos7840_port->ctrl_buf);
usb_free_urb(mos7840_port->control_urb);
@@ -2467,6 +2478,10 @@
del_timer_sync(&mos7840_port->led_timer1);
del_timer_sync(&mos7840_port->led_timer2);
+
+ usb_kill_urb(mos7840_port->led_urb);
+ usb_free_urb(mos7840_port->led_urb);
+ kfree(mos7840_port->led_dr);
}
usb_kill_urb(mos7840_port->control_urb);
usb_free_urb(mos7840_port->control_urb);
