Messages in this thread |  | | Date | Sun, 30 May 2021 11:17:21 +0300 | From | Eli Cohen <> | Subject | Re: [PATCH 2/2] vdpa/mlx5: Fix possible failure in umem size calculation |
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On Sun, May 30, 2021 at 04:05:57AM -0400, Michael S. Tsirkin wrote: > On Sun, May 30, 2021 at 09:32:14AM +0300, Eli Cohen wrote: > > umem size is a 32 bit unsigned value so assigning it to an int could > > cause false failures. Set the calculated value inside the function and > > modify function name to reflect the fact it updates the size. > > > > Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices") > > Signed-off-by: Eli Cohen <elic@nvidia.com> > > could you clarify the impact of the bug please? >
This was found by code revew. I did not see it causing trouble becuase umem sizes are small enough to fit in int. Nevertheless it's a bug that deserves a fix.
> > > --- > > drivers/vdpa/mlx5/net/mlx5_vnet.c | 15 +++++---------- > > 1 file changed, 5 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c > > index 53312f0460ad..fdf3e74bffbd 100644 > > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > > @@ -610,8 +610,8 @@ static void cq_destroy(struct mlx5_vdpa_net *ndev, u16 idx) > > mlx5_db_free(ndev->mvdev.mdev, &vcq->db); > > } > > > > -static int umem_size(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq, int num, > > - struct mlx5_vdpa_umem **umemp) > > +static void set_umem_size(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq, int num, > > + struct mlx5_vdpa_umem **umemp) > > { > > struct mlx5_core_dev *mdev = ndev->mvdev.mdev; > > int p_a; > > @@ -634,7 +634,7 @@ static int umem_size(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq > > *umemp = &mvq->umem3; > > break; > > } > > - return p_a * mvq->num_ent + p_b; > > + (*umemp)->size = p_a * mvq->num_ent + p_b; > > } > > > > static void umem_frag_buf_free(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_umem *umem) > > @@ -650,15 +650,10 @@ static int create_umem(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *m > > void *in; > > int err; > > __be64 *pas; > > - int size; > > struct mlx5_vdpa_umem *umem; > > > > - size = umem_size(ndev, mvq, num, &umem); > > - if (size < 0) > > - return size; > > - > > - umem->size = size; > > - err = umem_frag_buf_alloc(ndev, umem, size); > > + set_umem_size(ndev, mvq, num, &umem); > > + err = umem_frag_buf_alloc(ndev, umem, umem->size); > > if (err) > > return err; > > > > -- > > 2.31.1 >
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