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Date: Wed, 08 Aug 2012 09:37:09 +0200
From: Lars-Peter Clausen <lars@...afoo.de>
To: Peter Meerwald <pmeerw@...erw.net>
CC: Alexey Khoroshilov <khoroshilov@...ras.ru>,
Jonathan Cameron <jic23@....ac.uk>, linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org, ldv-project@...ras.ru
Subject: Re: [PATCH] iio/adjd_s311: Fix potential memory leak in adjd_s311_update_scan_mode()
On 08/08/2012 09:17 AM, Peter Meerwald wrote:
>
>> Do not leak memory by updating pointer with potentially
>> NULL realloc return value.
>
> I agree
>
> use of krealloc() was suggested in driver review (see
> http://www.spinics.net/lists/linux-iio/msg05930.html) to shorten the code;
> unfortunately, I misunderstood the semantics of krealloc() in case
> allocation fails
My fault I guess, sorry for that.
>
> this is the original code:
>
> kfree(data->buffer);
> data->buffer = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> if (!data->buffer)
> return -ENOMEM;
>
> I suggest to switch back to that original code, there is no need preserve
> the data in the buffer as krealloc does
Agreed.
>
> thanks, p.
>
>> Found by Linux Driver Verification project (linuxtesting.org).
>>
>> Signed-off-by: Alexey Khoroshilov <khoroshilov@...ras.ru>
>> ---
>> drivers/iio/light/adjd_s311.c | 14 ++++++++++----
>> 1 file changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/iio/light/adjd_s311.c b/drivers/iio/light/adjd_s311.c
>> index 1cbb449..0adda5b 100644
>> --- a/drivers/iio/light/adjd_s311.c
>> +++ b/drivers/iio/light/adjd_s311.c
>> @@ -271,12 +271,18 @@ static int adjd_s311_update_scan_mode(struct iio_dev *indio_dev,
>> const unsigned long *scan_mask)
>> {
>> struct adjd_s311_data *data = iio_priv(indio_dev);
>> - data->buffer = krealloc(data->buffer, indio_dev->scan_bytes,
>> + u16 *new_buffer;
>> + int ret = 0;
>> +
>> + new_buffer = krealloc(data->buffer, indio_dev->scan_bytes,
>> GFP_KERNEL);
>> - if (!data->buffer)
>> - return -ENOMEM;
>> + if (new_buffer == NULL) {
>> + kfree(data->buffer);
>> + ret = -ENOMEM;
>> + }
>> + data->buffer = new_buffer;
>>
>> - return 0;
>> + return ret;
>> }
>>
>> static const struct iio_info adjd_s311_info = {
>>
>
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