[PATCH RFT 1/5] iio: mxs-lradc: fix memory leak

Hi Marek,

Am 19.04.2016 um 12:32 schrieb Marek Vasut:

On 04/19/2016 08:33 AM, Stefan Wahren wrote:

quoted

Hi Marek,

Am 18.04.2016 um 19:16 schrieb Marek Vasut:

quoted

On 04/17/2016 12:08 PM, Jonathan Cameron wrote:

quoted

On 14/04/16 21:01, Marek Vasut wrote:

quoted

On 04/14/2016 05:48 PM, Stefan Wahren wrote:

quoted

After successful touchscreen registration the input device was
never freed. So fix this issue by using devm_input_allocate_device().

Signed-off-by: Stefan Wahren <redacted>
---
 drivers/iio/adc/mxs-lradc.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/adc/mxs-lradc.c b/drivers/iio/adc/mxs-lradc.c
index 33051b8..0576953 100644
--- a/drivers/iio/adc/mxs-lradc.c
+++ b/drivers/iio/adc/mxs-lradc.c

@@ -1109,12 +1109,11 @@ static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
 {
 	struct input_dev *input;
 	struct device *dev = lradc->dev;
-	int ret;
 
 	if (!lradc->use_touchscreen)
 		return 0;
 
-	input = input_allocate_device();
+	input = devm_input_allocate_device(dev);
 	if (!input)
 		return -ENOMEM;
 

@@ -1134,11 +1133,8 @@ static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
 
 	lradc->ts_input = input;
 	input_set_drvdata(input, lradc);
-	ret = input_register_device(input);
-	if (ret)
-		input_free_device(lradc->ts_input);
 
-	return ret;
+	return input_register_device(input);
 }
 
 static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)

Nice find.

Looks like at91_adc.c and exynos_adc.c suffer from the exact same issue.
The leak looks a bit more severe on exynos even, exynos_adc_ts_init()
could use a proper fail path. Do you want to send patches or shall I ?

As this has been there a long time I'm not going to rush it in as a fix.

I did take a proper look today and it seems they do the right thing
afterall. I checked them with kmemleak too to be sure.

thanks, input_unregister_device already free the memory.

Sorry for the mess :-(

I think it would be the best to remove / revert this patch.

This one? Why exactly? Please elaborate some more, so it's possible to
understand the reasoning :)

as you already pointed out this is not a memory leak, because
input_unregister_device free the input device. So the commit message is
incorrect.

This commit also simplifies the code but in this case we should also
remove input_unregister_device.

Regards
Stefan