2021-03-12 14:14:00

by Laurent Vivier

Subject: [PATCH] vhost: Fix vhost_vq_reset()

vhost_reset_is_le() is vhost_init_is_le(), and in the case of
cross-endian legacy, vhost_init_is_le() depends on vq->user_be.

vq->user_be is set by vhost_disable_cross_endian().

But in vhost_vq_reset(), we have:

vhost_reset_is_le(vq);
vhost_disable_cross_endian(vq);

And so user_be is used before being set.

To fix that, reverse the lines order as there is no other dependency
between them.

Signed-off-by: Laurent Vivier <[email protected]>
---
drivers/vhost/vhost.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a262e12c6dc2..5ccb0705beae 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -332,8 +332,8 @@ static void vhost_vq_reset(struct vhost_dev *dev,
vq->error_ctx = NULL;
vq->kick = NULL;
vq->log_ctx = NULL;
- vhost_reset_is_le(vq);
vhost_disable_cross_endian(vq);
+ vhost_reset_is_le(vq);
vq->busyloop_timeout = 0;
vq->umem = NULL;
vq->iotlb = NULL;
--
2.29.2

2021-03-15 08:33:51

by Jason Wang

Subject: Re: [PATCH] vhost: Fix vhost_vq_reset()

?? 2021/3/12 ????10:09, Laurent Vivier д??:
> vhost_reset_is_le() is vhost_init_is_le(), and in the case of
> cross-endian legacy, vhost_init_is_le() depends on vq->user_be.
>
> vq->user_be is set by vhost_disable_cross_endian().
>
> But in vhost_vq_reset(), we have:
>
> vhost_reset_is_le(vq);
> vhost_disable_cross_endian(vq);
>
> And so user_be is used before being set.
>
> To fix that, reverse the lines order as there is no other dependency
> between them.
>
> Signed-off-by: Laurent Vivier <[email protected]>


Acked-by: Jason Wang <[email protected]>


> ---
> drivers/vhost/vhost.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index a262e12c6dc2..5ccb0705beae 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -332,8 +332,8 @@ static void vhost_vq_reset(struct vhost_dev *dev,
> vq->error_ctx = NULL;
> vq->kick = NULL;
> vq->log_ctx = NULL;
> - vhost_reset_is_le(vq);
> vhost_disable_cross_endian(vq);
> + vhost_reset_is_le(vq);
> vq->busyloop_timeout = 0;
> vq->umem = NULL;
> vq->iotlb = NULL;

2021-03-17 08:28:45

by Stefano Garzarella

Subject: Re: [PATCH] vhost: Fix vhost_vq_reset()

On Fri, Mar 12, 2021 at 03:09:13PM +0100, Laurent Vivier wrote:
>vhost_reset_is_le() is vhost_init_is_le(), and in the case of
>cross-endian legacy, vhost_init_is_le() depends on vq->user_be.
>
>vq->user_be is set by vhost_disable_cross_endian().
>
>But in vhost_vq_reset(), we have:
>
> vhost_reset_is_le(vq);
> vhost_disable_cross_endian(vq);
>
>And so user_be is used before being set.
>
>To fix that, reverse the lines order as there is no other dependency
>between them.
>
>Signed-off-by: Laurent Vivier <[email protected]>
>---
> drivers/vhost/vhost.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Stefano Garzarella <[email protected]>