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SubjectRe: [PATCH v1 1/1] platform/mellanox: fix potential race in mlxbf-tmfifo driver
From
Vadim,

On 4/26/23 16:23, Liming Sun wrote:
> This commit adds memory barrier for the 'vq' update in function
> mlxbf_tmfifo_virtio_find_vqs() to avoid potential race due to
> out-of-order memory write. It also adds barrier for the 'is_ready'
> flag to make sure the initializations are visible before this flag
> is checked.
>
> Signed-off-by: Liming Sun <limings@nvidia.com>

Can you review this patch please ?

Regards,

Hans




> ---
> drivers/platform/mellanox/mlxbf-tmfifo.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
> index 91a077c35b8b..a79318e90a13 100644
> --- a/drivers/platform/mellanox/mlxbf-tmfifo.c
> +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c
> @@ -784,7 +784,7 @@ static void mlxbf_tmfifo_rxtx(struct mlxbf_tmfifo_vring *vring, bool is_rx)
> fifo = vring->fifo;
>
> /* Return if vdev is not ready. */
> - if (!fifo->vdev[devid])
> + if (!fifo || !fifo->vdev[devid])
> return;
>
> /* Return if another vring is running. */
> @@ -980,9 +980,13 @@ static int mlxbf_tmfifo_virtio_find_vqs(struct virtio_device *vdev,
>
> vq->num_max = vring->num;
>
> + vq->priv = vring;
> +
> + /* Make vq update visible before using it. */
> + virtio_mb(false);
> +
> vqs[i] = vq;
> vring->vq = vq;
> - vq->priv = vring;
> }
>
> return 0;
> @@ -1302,6 +1306,9 @@ static int mlxbf_tmfifo_probe(struct platform_device *pdev)
>
> mod_timer(&fifo->timer, jiffies + MLXBF_TMFIFO_TIMER_INTERVAL);
>
> + /* Make all updates visible before setting the 'is_ready' flag. */
> + virtio_mb(false);
> +
> fifo->is_ready = true;
> return 0;
>

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