[PATCH] drm: virtio: fix kmem_cache_alloc error check

[PATCH] drm: virtio: fix kmem_cache_alloc error check

[Gerd Hoffmann]

kmem_cache_alloc returns NULL on error, not ERR_PTR.

Fixes: f5985bf9cadd4e3ed8d5d9a9cbbb2e39cdb81cd9
Reported-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_vq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 472e349..9eb96fb2 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -97,8 +97,8 @@ void virtio_gpu_free_vbufs(struct virtio_gpu_device *vgdev)
 	struct virtio_gpu_vbuffer *vbuf;
 
 	vbuf = kmem_cache_alloc(vgdev->vbufs, GFP_KERNEL);
-	if (IS_ERR(vbuf))
-		return ERR_CAST(vbuf);
+	if (!vbuf)
+		return ERR_PTR(-ENOMEM);
 	memset(vbuf, 0, VBUFFER_SIZE);
 
 	BUG_ON(size > MAX_INLINE_CMD_SIZE);
-- 
1.8.3.1

Re: [PATCH] drm: virtio: fix kmem_cache_alloc error check

[Daniel Vetter]

On Mon, Mar 13, 2017 at 09:22:26AM +0100, Gerd Hoffmann wrote:
> kmem_cache_alloc returns NULL on error, not ERR_PTR.
> 
> Fixes: f5985bf9cadd4e3ed8d5d9a9cbbb2e39cdb81cd9
> Reported-by: Jiri Slaby <jslaby@suse.cz>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

I guess we should have smatch integrated into 0day to catch these ...

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/virtio/virtgpu_vq.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index 472e349..9eb96fb2 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -97,8 +97,8 @@ void virtio_gpu_free_vbufs(struct virtio_gpu_device *vgdev)
>  	struct virtio_gpu_vbuffer *vbuf;
>  
>  	vbuf = kmem_cache_alloc(vgdev->vbufs, GFP_KERNEL);
> -	if (IS_ERR(vbuf))
> -		return ERR_CAST(vbuf);
> +	if (!vbuf)
> +		return ERR_PTR(-ENOMEM);
>  	memset(vbuf, 0, VBUFFER_SIZE);
>  
>  	BUG_ON(size > MAX_INLINE_CMD_SIZE);
> -- 
> 1.8.3.1
> 
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> dri-devel@lists.freedesktop.org
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch