At 2023-03-19 00:39:13, "Jonathan Cameron" <jic23@xxxxxxxxxx> wrote:
>On Fri, 10 Mar 2023 17:12:39 +0800
>Zheng Wang <zyytlz.wz@xxxxxxx> wrote:
>
>> In at91_adc_probe, &st->touch_st.workq is bound with
>> at91_adc_workq_handler. Then it will be started by irq
>> handler at91_adc_touch_data_handler
>>
>> If we remove the driver which will call at91_adc_remove
>> to make cleanup, there may be a unfinished work.
>>
>> The possible sequence is as follows:
>>
>> Fix it by finishing the work before cleanup in the at91_adc_remove
>>
>> CPU0 CPU1
>>
>> |at91_adc_workq_handler
>> at91_adc_remove |
>> iio_device_unregister|
>> iio_dev_release |
>> kfree(iio_dev_opaque);|
>> |
>> |iio_push_to_buffers
>> |&iio_dev_opaque->buffer_list
>> |//use
>> Fixes: 23ec2774f1cc ("iio: adc: at91-sama5d2_adc: add support for position and pressure channels")
>> Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
>> ---
>> drivers/iio/adc/at91-sama5d2_adc.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
>> index 50d02e5fc6fc..1b95d18d9e0b 100644
>> --- a/drivers/iio/adc/at91-sama5d2_adc.c
>> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
>> @@ -2495,6 +2495,8 @@ static int at91_adc_remove(struct platform_device *pdev)
>> struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>> struct at91_adc_state *st = iio_priv(indio_dev);
>>
>> + disable_irq_nosync(st->irq);
>> + cancel_work_sync(&st->touch_st.workq);
>
>I'd like some input form someone more familiar with this driver than I am.
>
>In particular, whilst it fixes the bug seen I'm not sure what the most
>logical ordering for the disable is or the best way to do it.
>
>I'd prefer to see the irq cut off at source by disabling it at the device
>feature that is generating the irq followed by cancelling or waiting for
>completion of any in flight work.
Hi,
Sorry for my late reply. I think we need to replace disable_irq_nosync with free_irq.
Thanks,
Zheng
>
>> iio_device_unregister(indio_dev);
>>
>> at91_adc_dma_disable(st);
