In vb2_dc_alloc(), get_device() is called to increment the device
reference count. However, if subsequent DMA allocation fails
(vb2_dc_alloc_coherent or vb2_dc_alloc_non_coherent returns error),
the function returns without calling put_device(), causing a device
reference leak.

Add put_device() call in the error path before kfree() to properly
release the device reference acquired earlier.

Fixes: de27891f675e ("media: videobuf2: handle non-contiguous DMA allocations")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
---
 drivers/media/common/videobuf2/videobuf2-dma-contig.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index a13ec569c82f..7123c5fae92c 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -258,6 +258,7 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
 
 	if (ret) {
 		dev_err(dev, "dma alloc of size %lu failed\n", size);
+		put_device(buf->dev);
 		kfree(buf);
 		return ERR_PTR(-ENOMEM);
 	}
-- 
2.50.1.windows.1

On 28.10.2025 07:44, Haotian Zhang wrote:
> In vb2_dc_alloc(), get_device() is called to increment the device
> reference count. However, if subsequent DMA allocation fails
> (vb2_dc_alloc_coherent or vb2_dc_alloc_non_coherent returns error),
> the function returns without calling put_device(), causing a device
> reference leak.
>
> Add put_device() call in the error path before kfree() to properly
> release the device reference acquired earlier.
>
> Fixes: de27891f675e ("media: videobuf2: handle non-contiguous DMA allocations")
> Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>   drivers/media/common/videobuf2/videobuf2-dma-contig.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> index a13ec569c82f..7123c5fae92c 100644
> --- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> +++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
> @@ -258,6 +258,7 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
>   
>   	if (ret) {
>   		dev_err(dev, "dma alloc of size %lu failed\n", size);
> +		put_device(buf->dev);
>   		kfree(buf);
>   		return ERR_PTR(-ENOMEM);
>   	}

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland