From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.kundenserver.de ([212.227.17.24]:58366 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752662AbcDSNiT (ORCPT ); Tue, 19 Apr 2016 09:38:19 -0400 Subject: Re: [PATCH RFT 1/5] iio: mxs-lradc: fix memory leak To: Marek Vasut , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler References: <1460648909-2657-1-git-send-email-stefan.wahren@i2se.com> <1460648909-2657-2-git-send-email-stefan.wahren@i2se.com> <570FF70F.3000501@denx.de> <571360A3.3060809@kernel.org> <57151652.4020709@denx.de> <5715D12D.1020303@i2se.com> <57160937.6000903@denx.de> Cc: Ksenija Stanojevic , Fabio Estevam , Juergen Borleis , Alexandre Belloni , linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Greg Kroah-Hartman From: Stefan Wahren Message-ID: <5716348F.70200@i2se.com> Date: Tue, 19 Apr 2016 15:37:19 +0200 MIME-Version: 1.0 In-Reply-To: <57160937.6000903@denx.de> Content-Type: text/plain; charset=utf-8 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org Hi Marek, Am 19.04.2016 um 12:32 schrieb Marek Vasut: > On 04/19/2016 08:33 AM, Stefan Wahren wrote: >> Hi Marek, >> >> Am 18.04.2016 um 19:16 schrieb Marek Vasut: >>> On 04/17/2016 12:08 PM, Jonathan Cameron wrote: >>>> On 14/04/16 21:01, Marek Vasut wrote: >>>>> On 04/14/2016 05:48 PM, Stefan Wahren wrote: >>>>>> 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 >>>>>> --- >>>>>> 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