Re: [PATCH] vhost: initialize vq->nheads properly

[JAEHOON KIM <jhkim@linux.ibm.com>]

On 7/29/2025 2:39 AM, Jason Wang wrote:
> Commit 7918bb2d19c9 ("vhost: basic in order support") introduces
> vq->nheads to store the number of batched used buffers per used elem
> but it forgets to initialize the vq->nheads to NULL in
> vhost_dev_init() this will cause kfree() that would try to free it
> without be allocated if SET_OWNER is not called.
>
> Reported-by: JAEHOON KIM <jhkim@linux.ibm.com>
> Reported-by: Breno Leitao <leitao@debian.org>
> Fixes: 7918bb2d19c9 ("vhost: basic in order support")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>   drivers/vhost/vhost.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index a4873d116df1..b4dfe38c7008 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -615,6 +615,7 @@ void vhost_dev_init(struct vhost_dev *dev,
>   		vq->log = NULL;
>   		vq->indirect = NULL;
>   		vq->heads = NULL;
> +		vq->nheads = NULL;
>   		vq->dev = dev;
>   		mutex_init(&vq->mutex);
>   		vhost_vq_reset(dev, vq);
>
checked and confirmed no crash occurs.
Thanks for the fast update.

Tested-by: Jaehoon Kim <jhkim@linux.ibm.com>