Re: [PATCH v2] dmaengine: sun6i-dma: Fix memory leak in sun6i_dma_terminate_all

[Hongling Zeng <zhongling0719@126.com>]

Hi Frank and Jernej Skrabec:

      Thanks for all the review!

   You're absolutely right.After checking virt-dma.h, I see that 
desc_terminated is the correct queue for actively terminated transfers. 
I'll update to use:

   - vchan_terminate_vdesc(vd);

   I'll send v3 ,Please help to review.

   Best regards,
   Hongling Zeng

在 2026年06月17日 04:47, Frank Li 写道:
> On Tue, Jun 16, 2026 at 02:04:49PM +0800, Hongling Zeng wrote:
>> When terminating a non-cyclic DMA transfer, the active descriptor
>> is not properly reclaimed. The descriptor is removed from the
>> desc_issued list in sun6i_dma_start_desc(), but in
>> sun6i_dma_terminate_all(), only cyclic transfer descriptors are
>> added to the desc_completed list before cleanup.
>>
>> For non-cyclic transfers, pchan->desc is set to NULL without first
>> adding the descriptor back to a list that vchan_get_all_descriptors()
>> can collect. This causes the descriptor and its associated LLI chain
>> to be permanently leaked.
>>
>> Fix by ensuring both cyclic and non-cyclic active descriptors are
>> added to the desc_completed list before setting pchan->desc to NULL.
>>
>> Fixes: 555859308723 ("dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller")
>> Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
>>
>> ---
>>   Change in v2;
>>   -Add pchan->desc != pchan->done check to prevent race condition
>>    where completed descriptors could be double-added to desc_completed
>>    list, causing list corruption
>> ---
>>   drivers/dma/sun6i-dma.c | 12 +++++-------
>>   1 file changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
>> index 7a79f346250a..12d038ef5f2e 100644
>> --- a/drivers/dma/sun6i-dma.c
>> +++ b/drivers/dma/sun6i-dma.c
>> @@ -946,16 +946,14 @@ static int sun6i_dma_terminate_all(struct dma_chan *chan)
>>
>>   	spin_lock_irqsave(&vchan->vc.lock, flags);
>>
>> -	if (vchan->cyclic) {
>> -		vchan->cyclic = false;
>> -		if (pchan && pchan->desc) {
>> -			struct virt_dma_desc *vd = &pchan->desc->vd;
>> -			struct virt_dma_chan *vc = &vchan->vc;
>> +	if (pchan && pchan->desc && pchan->desc != pchan->done) {
>> +		struct virt_dma_desc *vd = &pchan->desc->vd;
>> +		struct virt_dma_chan *vc = &vchan->vc;
>>
>> -			list_add_tail(&vd->node, &vc->desc_completed);
>> -		}
>> +		list_add_tail(&vd->node, &vc->desc_completed);
> should It be in desc_terminated queue?
>
> ref: https://lore.kernel.org/dmaengine/ajETw7uwVx_U9o5F@ryzen/T/#m541c24b45fb425c6a8a81d800db225b58411447e
>
> Frank
>>   	}
>>
>> +	vchan->cyclic = false;
>>   	vchan_get_all_descriptors(&vchan->vc, &head);
>>
>>   	if (pchan) {
>> --
>> 2.25.1
>>