Re: [PATCH v4] dmaengine: sun6i-dma: Fix memory leak in sun6i_dma_terminate_all

[Hongling Zeng]

在 2026年06月30日 19:34, Vinod Koul 写道:
> On 18-06-26, 10:06, Hongling Zeng wrote:
> > When terminating DMA transfers, active descriptors are not properly
> > reclaimed. Only cyclic descriptors were handled, leaving non-cyclic
> > descriptors and their LLI chains to be permanently leaked.
> >
> > Fix by using vchan_terminate_vdesc() which handles both cyclic and
> > non-cyclic descriptors by adding them to desc_terminated queue for
> > proper cleanup.
> >
> > Add pchan->desc != pchan->done check to prevent double-adding completed
> > descriptors, which would corrupt the list.
> Thanks for the patch. Please consider revising the subject which should
> describe the changes in the patch and not the fix/issue.
>
> A better one would be "fix reclaim descriptors while terminating"
  Thank you for the suggestion. I'll update the subject in v5 to describe
  the changes rather than the issue.

> > Fixes: 555859308723 ("dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller")
> > Signed-off-by: Hongling Zeng <zenghongling@xxxxxxxxxx>
> > Acked-by: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
> > Suggested-by: Frank Li <Frank.li@xxxxxxxxxxx>
> >
> > ---
> >   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
> > ---
> >   Change in v3:
> >   -Fix by using vchan_terminate_vdesc() as suggested by Frank Li
> > ---
> >   Change in v4:
> >   -Correct the commit message
> > ---
> >   drivers/dma/sun6i-dma.c | 13 +++++--------
> >   1 file changed, 5 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> > index 7a79f346250a..134ae840f176 100644
> > --- a/drivers/dma/sun6i-dma.c
> > +++ b/drivers/dma/sun6i-dma.c
> > @@ -946,16 +946,13 @@ 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;
> > -
> > -			list_add_tail(&vd->node, &vc->desc_completed);
> > -		}
> > +	if (pchan && pchan->desc && pchan->desc != pchan->done) {
> > +		struct virt_dma_desc *vd = &pchan->desc->vd;
> > +		
> > +		vchan_terminate_vdesc(vd);
> >   	}
> >   
> > +	vchan->cyclic = false;
> >   	vchan_get_all_descriptors(&vchan->vc, &head);
> >   
> >   	if (pchan) {
> > --
> > 2.25.1