[082/141] USB: mos7840: fix DMA to stack

Steven Rostedt
2013-07-03T19:03:14Z

[-- Attachment #1: 0082-USB-mos7840-fix-DMA-to-stack.patch --]
[-- Type: text/plain, Size: 3330 bytes --]

3.6.11.6 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Johan Hovold <jhovold@gmail.com>

[ Upstream commit 15ee89c3347fbf58a4361011eda5ac2731e45126 ]

Fix regression introduced by commit 0eafe4de1a ("USB: serial: mos7840:
add support for MCS7810 devices") which used stack-allocated buffers for
control messages.

Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
drivers/usb/serial/mos7840.c | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 8654df0..3193d25 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -2341,13 +2341,21 @@ static int mos7840_ioctl(struct tty_struct *tty,
static int mos7810_check(struct usb_serial *serial)
{
int i, pass_count = 0;
+ u8 *buf;
__u16 data = 0, mcr_data = 0;
__u16 test_pattern = 0x55AA;
+ int res;
+
+ buf = kmalloc(VENDOR_READ_LENGTH, GFP_KERNEL);
+ if (!buf)
+ return 0; /* failed to identify 7810 */

/* Store MCR setting */
- usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
+ res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
MCS_RDREQ, MCS_RD_RTYPE, 0x0300, MODEM_CONTROL_REGISTER,
- &mcr_data, VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
+ buf, VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
+ if (res == VENDOR_READ_LENGTH)
+ mcr_data = *buf;

for (i = 0; i < 16; i++) {
/* Send the 1-bit test pattern out to MCS7810 test pin */
@@ -2357,9 +2365,12 @@ static int mos7810_check(struct usb_serial *serial)
MODEM_CONTROL_REGISTER, NULL, 0, MOS_WDR_TIMEOUT);

/* Read the test pattern back */
- usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
- MCS_RDREQ, MCS_RD_RTYPE, 0, GPIO_REGISTER, &data,
- VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
+ res = usb_control_msg(serial->dev,
+ usb_rcvctrlpipe(serial->dev, 0), MCS_RDREQ,
+ MCS_RD_RTYPE, 0, GPIO_REGISTER, buf,
+ VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
+ if (res == VENDOR_READ_LENGTH)
+ data = *buf;

/* If this is a MCS7810 device, both test patterns must match */
if (((test_pattern >> i) ^ (~data >> 1)) & 0x0001)
@@ -2373,6 +2384,8 @@ static int mos7810_check(struct usb_serial *serial)
MCS_WR_RTYPE, 0x0300 | mcr_data, MODEM_CONTROL_REGISTER, NULL,
0, MOS_WDR_TIMEOUT);

+ kfree(buf);
+
if (pass_count == 16)
return 1;

@@ -2382,11 +2395,17 @@ static int mos7810_check(struct usb_serial *serial)
static int mos7840_calc_num_ports(struct usb_serial *serial)
{
__u16 data = 0x00;
+ u8 *buf;
int mos7840_num_ports;

- usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
- MCS_RDREQ, MCS_RD_RTYPE, 0, GPIO_REGISTER, &data,
- VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
+ buf = kzalloc(VENDOR_READ_LENGTH, GFP_KERNEL);
+ if (buf) {
+ usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
+ MCS_RDREQ, MCS_RD_RTYPE, 0, GPIO_REGISTER, buf,
+ VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
+ data = *buf;
+ kfree(buf);
+ }

if (serial->dev->descriptor.idProduct == MOSCHIP_DEVICE_ID_7810 ||
serial->dev->descriptor.idProduct == MOSCHIP_DEVICE_ID_7820) {
--
1.7.10.4