2022-01-07 21:14:03

by Tom Rix

Subject: [PATCH] vdpa/mlx5: fix error handling in mlx5_vdpa_dev_add()

From: Tom Rix <[email protected]>

Clang build fails with
mlx5_vnet.c:2574:6: error: variable 'mvdev' is used uninitialized whenever
'if' condition is true
if (!ndev->vqs || !ndev->event_cbs) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mlx5_vnet.c:2660:14: note: uninitialized use occurs here
put_device(&mvdev->vdev.dev);
^~~~~
This because mvdev is set after trying to allocate ndev->vqs,event_cbs.
So move the allocation to after mvdev is set but before the arrays
are used in init_mvqs()

Fixes: 7620d51af29a ("vdpa/mlx5: Support configuring max data virtqueue")
Signed-off-by: Tom Rix <[email protected]>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index b564c70475815..37220f6db7ad7 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2569,16 +2569,18 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
if (IS_ERR(ndev))
return PTR_ERR(ndev);

+ ndev->mvdev.mlx_features = mgtdev->mgtdev.supported_features;
+ ndev->mvdev.max_vqs = max_vqs;
+ mvdev = &ndev->mvdev;
+ mvdev->mdev = mdev;
+
ndev->vqs = kcalloc(max_vqs, sizeof(*ndev->vqs), GFP_KERNEL);
ndev->event_cbs = kcalloc(max_vqs + 1, sizeof(*ndev->event_cbs), GFP_KERNEL);
if (!ndev->vqs || !ndev->event_cbs) {
err = -ENOMEM;
goto err_alloc;
}
- ndev->mvdev.mlx_features = mgtdev->mgtdev.supported_features;
- ndev->mvdev.max_vqs = max_vqs;
- mvdev = &ndev->mvdev;
- mvdev->mdev = mdev;
+
init_mvqs(ndev);
mutex_init(&ndev->reslock);
config = &ndev->config;
--
2.26.3

2022-01-08 01:50:07

by Si-Wei Liu

Subject: Re: [PATCH] vdpa/mlx5: fix error handling in mlx5_vdpa_dev_add()

The proposed fix looks fine, but I still hope this to revert this series
if at all possible. The review hadn't been done yet.

On 1/7/2022 1:13 PM, [email protected] wrote:
> From: Tom Rix <[email protected]>
>
> Clang build fails with
> mlx5_vnet.c:2574:6: error: variable 'mvdev' is used uninitialized whenever
> 'if' condition is true
> if (!ndev->vqs || !ndev->event_cbs) {
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> mlx5_vnet.c:2660:14: note: uninitialized use occurs here
> put_device(&mvdev->vdev.dev);
> ^~~~~
> This because mvdev is set after trying to allocate ndev->vqs,event_cbs.
> So move the allocation to after mvdev is set but before the arrays
> are used in init_mvqs()
>
> Fixes: 7620d51af29a ("vdpa/mlx5: Support configuring max data virtqueue")
> Signed-off-by: Tom Rix <[email protected]>

Reviewed-by: Si-Wei Liu<[email protected]>
> ---
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index b564c70475815..37220f6db7ad7 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2569,16 +2569,18 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
> if (IS_ERR(ndev))
> return PTR_ERR(ndev);
>
> + ndev->mvdev.mlx_features = mgtdev->mgtdev.supported_features;
> + ndev->mvdev.max_vqs = max_vqs;
> + mvdev = &ndev->mvdev;
> + mvdev->mdev = mdev;
> +
> ndev->vqs = kcalloc(max_vqs, sizeof(*ndev->vqs), GFP_KERNEL);
> ndev->event_cbs = kcalloc(max_vqs + 1, sizeof(*ndev->event_cbs), GFP_KERNEL);
> if (!ndev->vqs || !ndev->event_cbs) {
> err = -ENOMEM;
> goto err_alloc;
> }
> - ndev->mvdev.mlx_features = mgtdev->mgtdev.supported_features;
> - ndev->mvdev.max_vqs = max_vqs;
> - mvdev = &ndev->mvdev;
> - mvdev->mdev = mdev;
> +
> init_mvqs(ndev);
> mutex_init(&ndev->reslock);
> config = &ndev->config;