[PATCH v2] iio: adc: ad7192: fix null pointer de-reference crash during probe

Alexandru Ardelean
2020-04-07T06:34:15Z

When the 'spi_device_id' table was removed, it omitted to cleanup/fix the
assignment:
'indio_dev->name = spi_get_device_id(spi)->name;'

After that patch 'spi_get_device_id(spi)' returns NULL, so this crashes
during probe with null de-ref.

This change assigns the 'compatible' string from the DT table, as the new
'indio_dev->name'. As such, the new device/part name now looks like
'adi,ad719x', and now has the vendor prefix.

Note that this change is not doing any NULL check to the return value of
'of_match_device()'. This shouldn't happen, and if it does it's likely a
framework error on the probe side.

Fixes: 66614ab2be38 ("staging: iio: adc: ad7192: removed spi_device_id")
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---

Changelog v1 -> v2:
* fix colon for Fixes tag
* updated commit title a bit; to make it longer

drivers/iio/adc/ad7192.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index 8ec28aa8fa8a..0039a45e1f33 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -888,6 +888,7 @@ MODULE_DEVICE_TABLE(of, ad7192_of_match);

static int ad7192_probe(struct spi_device *spi)
{
+ const struct of_device_id *of_id;
struct ad7192_state *st;
struct iio_dev *indio_dev;
int ret, voltage_uv = 0;
@@ -937,10 +938,12 @@ static int ad7192_probe(struct spi_device *spi)
goto error_disable_avdd;
}

+ of_id = of_match_device(ad7192_of_match, &spi->dev);
+
spi_set_drvdata(spi, indio_dev);
- st->devid = (unsigned long)of_device_get_match_data(&spi->dev);
+ st->devid = (unsigned long)of_id->data;
indio_dev->dev.parent = &spi->dev;
- indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->name = of_id->compatible;
indio_dev->modes = INDIO_DIRECT_MODE;

ret = ad7192_channels_config(indio_dev);
--
2.17.1