redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

iio:adc:ti-adc0832 Fix alignment issue with timestamp 

commit 39e91f3be4 upstream.

One of a class of bugs pointed out by Lars in a recent review.
iio_push_to_buffers_with_timestamp assumes the buffer used is aligned
to the size of the timestamp (8 bytes).  This is not guaranteed in
this driver which uses an array of smaller elements on the stack.

We fix this issues by moving to a suitable structure in the iio_priv()
data with alignment explicitly requested.  This data is allocated
with kzalloc so no data can leak apart from previous readings.
Note that previously no data could leak 'including' previous readings
but I don't think it is an issue to potentially leak them like
this now does.

In this case the postioning of the timestamp is depends on what
other channels are enabled. As such we cannot use a structure to
make the alignment explicit as it would be missleading by suggesting
only one possible location for the timestamp.

Fixes: 815bbc8746 ("iio: ti-adc0832: add triggered buffer support")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200722155103.979802-25-jic23@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Jonathan Cameron 2020-07-22 16:51:00 +01:00 committed by Greg Kroah-Hartman
parent a8c59abdbc
commit 96a5134423
1 changed files with 8 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/iio/adc/ti-adc0832.c
View File

@ -28,6 +28,12 @@ struct adc0832 {
struct regulator *reg;
struct mutex lock;
u8 mux_bits;
/*
* Max size needed: 16x 1 byte ADC data + 8 bytes timestamp
* May be shorter if not all channels are enabled subject
* to the timestamp remaining 8 byte aligned.
*/
u8 data[24] __aligned(8);
u8 tx_buf[2] ____cacheline_aligned;
u8 rx_buf[2];
@ -199,7 +205,6 @@ static irqreturn_t adc0832_trigger_handler(int irq, void *p)
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct adc0832 *adc = iio_priv(indio_dev);
u8 data[24] = { }; /* 16x 1 byte ADC data + 8 bytes timestamp */
int scan_index;
int i = 0;
@ -217,10 +222,10 @@ static irqreturn_t adc0832_trigger_handler(int irq, void *p)
goto out;
}
data[i] = ret;
adc->data[i] = ret;
i++;
}
iio_push_to_buffers_with_timestamp(indio_dev, data,
iio_push_to_buffers_with_timestamp(indio_dev, adc->data,
iio_get_time_ns(indio_dev));
out:
mutex_unlock(&adc->lock);