Re: [PATCH] iio: inkern: fix a static checker error

From: Peter Rosin
Date: Mon Apr 24 2017 - 05:32:58 EST


On 2017-04-20 23:13, Peter Rosin wrote:
> On 2017-04-20 23:12, Lars-Peter Clausen wrote:
>> On 04/20/2017 11:01 PM, Peter Rosin wrote:
>>> Avoid this smatch error:
>>> drivers/iio/inkern.c:751 iio_read_avail_channel_raw() error: double unlock 'mutex:&chan->indio_dev->info_exist_lock'
>>
>> Looks good, but it's not just the smatch error, this is a real issue. This
>> even seems to be a endless loop, always jumping back to err_unlock.
>
> Yes, it should probably go to stable too...

Nope, not an endless loop, but I of course only noticed after sending
a v2 [1] which falsely stated just that. Ignore that v2 patch and take
this one instead, for the reasons stated in my followup [2] to that
message.

Involving stable is probably not needed either...

Cheers,
peda

[1] https://lkml.org/lkml/2017/4/24/179
[2] https://lkml.org/lkml/2017/4/24/221

>>>
>>> Fixes: 00c5f80c2fad ("iio: inkern: add helpers to query available values from channels")
>>> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
>>
>>> ---
>>> drivers/iio/inkern.c | 4 +---
>>> 1 file changed, 1 insertion(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
>>> index 7a13535dc3e9..a3941bade6a7 100644
>>> --- a/drivers/iio/inkern.c
>>> +++ b/drivers/iio/inkern.c
>>> @@ -750,11 +750,9 @@ int iio_read_avail_channel_raw(struct iio_channel *chan,
>>> err_unlock:
>>> mutex_unlock(&chan->indio_dev->info_exist_lock);
>>>
>>> - if (ret >= 0 && type != IIO_VAL_INT) {
>>> + if (ret >= 0 && type != IIO_VAL_INT)
>>> /* raw values are assumed to be IIO_VAL_INT */
>>> ret = -EINVAL;
>>> - goto err_unlock;
>>> - }
>>>
>>> return ret;
>>> }
>>>
>>
>