Hi!
From: Mauro Carvalho Chehab mchehab+huawei@kernel.org
[ Upstream commit a2ab06d7c4d6bfd0b545a768247a70463e977e27 ]
Using stack-allocated pointers for USB message data don't work. This driver is almost OK with that, except for the I2C read logic.
Fix it by using a temporary read buffer, just like on all other calls to m920x_read().
This introduces memory leak... and I don't believe it really fixes the problem.
index eafc5c82467f4..5b806779e2106 100644 --- a/drivers/media/usb/dvb-usb/m920x.c +++ b/drivers/media/usb/dvb-usb/m920x.c @@ -284,6 +284,13 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu /* Should check for ack here, if we knew how. */ } if (msg[i].flags & I2C_M_RD) {
char *read = kmalloc(1, GFP_KERNEL);if (!read) {ret = -ENOMEM;kfree(read);goto unlock;}
kfree(NULL);
for (j = 0; j < msg[i].len; j++) { /* Last byte of transaction? * Send STOP, otherwise send ACK. */@@ -291,9 +298,12 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu if ((ret = m920x_read(d->udev, M9206_I2C, 0x0, 0x20 | stop,
&msg[i].buf[j], 1)) != 0)
read, 1)) != 0) goto unlock;
Memory leak of read.
msg[i].buf[j] = read[0]; }kfree(read);
But more importantly, do we have exact copy of the read problem just below, during write?
Best regards, Pavel
diff --git a/drivers/media/usb/dvb-usb/m920x.c b/drivers/media/usb/dvb-usb/m920x.c index 691e05833db1..e5ee54324a28 100644 --- a/drivers/media/usb/dvb-usb/m920x.c +++ b/drivers/media/usb/dvb-usb/m920x.c @@ -250,7 +250,7 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu { struct dvb_usb_device *d = i2c_get_adapdata(adap); int i, j; - int ret = 0; + int ret;
if (mutex_lock_interruptible(&d->i2c_mutex) < 0) return -EAGAIN; @@ -277,7 +277,6 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu char *read = kmalloc(1, GFP_KERNEL); if (!read) { ret = -ENOMEM; - kfree(read); goto unlock; }
@@ -288,8 +287,10 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu
if ((ret = m920x_read(d->udev, M9206_I2C, 0x0, 0x20 | stop, - read, 1)) != 0) + read, 1)) != 0) { + kfree(read); goto unlock; + } msg[i].buf[j] = read[0]; }