diff mbox series

[30/32] iio:adc:ti-adc12138 Fix alignment issue with timestamp

Message ID 20200607155408.958437-31-jic23@kernel.org (mailing list archive)
State New, archived
Headers show
Series IIO: Fused set 1 and 2 of timestamp alignment fixes | expand

Commit Message

Jonathan Cameron June 7, 2020, 3:54 p.m. UTC 
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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 move 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 leak at all could occur, but previous readings should never
be a problem.

Fixes: 50a6edb1b6e0 ("iio: adc: add ADC12130/ADC12132/ADC12138 ADC driver")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/adc/ti-adc12138.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/iio/adc/ti-adc12138.c b/drivers/iio/adc/ti-adc12138.c
index e485719cd2c4..16f4fd7a04d9 100644
--- a/drivers/iio/adc/ti-adc12138.c
+++ b/drivers/iio/adc/ti-adc12138.c
@@ -47,6 +47,8 @@  struct adc12138 {
 	struct completion complete;
 	/* The number of cclk periods for the S/H's acquisition time */
 	unsigned int acquisition_time;
+	 /* 16x 2 bytes ADC data + 8 bytes timestamp */
+	__be16 data[20] __aligned(8);
 
 	u8 tx_buf[2] ____cacheline_aligned;
 	u8 rx_buf[2];
@@ -329,7 +331,6 @@  static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct adc12138 *adc = iio_priv(indio_dev);
-	__be16 data[20] = { }; /* 16x 2 bytes ADC data + 8 bytes timestamp */
 	__be16 trash;
 	int ret;
 	int scan_index;
@@ -345,7 +346,7 @@  static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 		reinit_completion(&adc->complete);
 
 		ret = adc12138_start_and_read_conv(adc, scan_chan,
-						   i ? &data[i - 1] : &trash);
+					i ? &adc->data[i - 1] : &trash);
 		if (ret) {
 			dev_warn(&adc->spi->dev,
 				 "failed to start conversion\n");
@@ -362,7 +363,7 @@  static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 	}
 
 	if (i) {
-		ret = adc12138_read_conv_data(adc, &data[i - 1]);
+		ret = adc12138_read_conv_data(adc, &adc->data[i - 1]);
 		if (ret) {
 			dev_warn(&adc->spi->dev,
 				 "failed to get conversion data\n");
@@ -370,7 +371,7 @@  static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 		}
 	}
 
-	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);