[PATCH] virtio_ring: fix uninitialized symbol warnings

[PATCH] virtio_ring: fix uninitialized symbol warnings

[Chelsy Ratnawat]

Fix below smatch warnings:
  virtio_ring.c:1566 virtqueue_add_packed() error: uninitialized symbol 'prev'.
  virtio_ring.c:1574 virtqueue_add_packed() error: uninitialized symbol 'head_flags'.
  virtio_ring.c:635 virtqueue_add_split() error: uninitialized symbol 'prev'.

No functional changes intended.

Signed-off-by: Chelsy Ratnawat <chelsyratnawat2001@gmail.com>
---
 drivers/virtio/virtio_ring.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index f5062061c408..03aa08aaebed 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -540,7 +540,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 	struct vring_desc_extra *extra;
 	struct scatterlist *sg;
 	struct vring_desc *desc;
-	unsigned int i, n, avail, descs_used, prev, err_idx;
+	unsigned int i, n, avail, descs_used, prev = 0, err_idx;
 	int head;
 	bool indirect;
 
@@ -1459,8 +1459,8 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
 	struct vring_packed_desc *desc;
 	struct scatterlist *sg;
 	unsigned int i, n, c, descs_used, err_idx, len;
-	__le16 head_flags, flags;
-	u16 head, id, prev, curr, avail_used_flags;
+	__le16 head_flags = 0, flags;
+	u16 head, id, prev = 0, curr, avail_used_flags;
 	int err;
 
 	START_USE(vq);
-- 
2.47.3

Re: [PATCH] virtio_ring: fix uninitialized symbol warnings

[Michael S. Tsirkin]

On Wed, Aug 06, 2025 at 05:41:01AM -0700, Chelsy Ratnawat wrote:
> Fix below smatch warnings:
>   virtio_ring.c:1566 virtqueue_add_packed() error: uninitialized symbol 'prev'.
>   virtio_ring.c:1574 virtqueue_add_packed() error: uninitialized symbol 'head_flags'.
>   virtio_ring.c:635 virtqueue_add_split() error: uninitialized symbol 'prev'.
> 
> No functional changes intended.
> 
> Signed-off-by: Chelsy Ratnawat <chelsyratnawat2001@gmail.com>


Sorry we don't mechanically "fix" warnings like this. 
Please analyse the code and report whether the issue is
real or a false positive.


> ---
>  drivers/virtio/virtio_ring.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index f5062061c408..03aa08aaebed 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -540,7 +540,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
>  	struct vring_desc_extra *extra;
>  	struct scatterlist *sg;
>  	struct vring_desc *desc;
> -	unsigned int i, n, avail, descs_used, prev, err_idx;
> +	unsigned int i, n, avail, descs_used, prev = 0, err_idx;
>  	int head;
>  	bool indirect;
>  
> @@ -1459,8 +1459,8 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
>  	struct vring_packed_desc *desc;
>  	struct scatterlist *sg;
>  	unsigned int i, n, c, descs_used, err_idx, len;
> -	__le16 head_flags, flags;
> -	u16 head, id, prev, curr, avail_used_flags;
> +	__le16 head_flags = 0, flags;
> +	u16 head, id, prev = 0, curr, avail_used_flags;
>  	int err;
>  
>  	START_USE(vq);
> -- 
> 2.47.3