2023-03-02 17:28:39

by Harshit Mogalapalli

Subject: [PATCH 5.10.y] drm/virtio: Fix error code in virtio_gpu_object_shmem_init()

In virtio_gpu_object_shmem_init() we are passing NULL to PTR_ERR, which
is returning 0/success.

Fix this by storing error value in 'ret' variable before assigning
shmem->pages to NULL.

Found using static analysis with Smatch.

Fixes: 64b88afbd92f ("drm/virtio: Correct drm_gem_shmem_get_sg_table() error handling")
Signed-off-by: Harshit Mogalapalli <[email protected]>
---
Only compile tested.

Upstream commit b5c9ed70d1a9 ("drm/virtio: Improve DMA API usage for shmem BOs")
deleted this code, so this patch is not necessary in linux-6.1.y and
linux-6.2.y.
---
drivers/gpu/drm/virtio/virtgpu_object.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 168148686001..49fa59e09187 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -159,8 +159,9 @@ static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
shmem->pages = drm_gem_shmem_get_sg_table(&bo->base.base);
if (IS_ERR(shmem->pages)) {
drm_gem_shmem_unpin(&bo->base.base);
+ ret = PTR_ERR(shmem->pages);
shmem->pages = NULL;
- return PTR_ERR(shmem->pages);
+ return ret;
}

if (use_dma_api) {
--
2.31.1

2023-03-03 21:32:22

by Dmitry Osipenko

Subject: Re: [PATCH 5.10.y] drm/virtio: Fix error code in virtio_gpu_object_shmem_init()

On 3/2/23 20:28, Harshit Mogalapalli wrote:
> In virtio_gpu_object_shmem_init() we are passing NULL to PTR_ERR, which
> is returning 0/success.
>
> Fix this by storing error value in 'ret' variable before assigning
> shmem->pages to NULL.
>
> Found using static analysis with Smatch.
>
> Fixes: 64b88afbd92f ("drm/virtio: Correct drm_gem_shmem_get_sg_table() error handling")
> Signed-off-by: Harshit Mogalapalli <[email protected]>
> ---
> Only compile tested.
>
> Upstream commit b5c9ed70d1a9 ("drm/virtio: Improve DMA API usage for shmem BOs")
> deleted this code, so this patch is not necessary in linux-6.1.y and
> linux-6.2.y.
> ---
> drivers/gpu/drm/virtio/virtgpu_object.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
> index 168148686001..49fa59e09187 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -159,8 +159,9 @@ static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
> shmem->pages = drm_gem_shmem_get_sg_table(&bo->base.base);
> if (IS_ERR(shmem->pages)) {
> drm_gem_shmem_unpin(&bo->base.base);
> + ret = PTR_ERR(shmem->pages);
> shmem->pages = NULL;
> - return PTR_ERR(shmem->pages);
> + return ret;
> }
>
> if (use_dma_api) {

Reviewed-by: Dmitry Osipenko <[email protected]>

--
Best regards,
Dmitry