RE: [PATCH] vdpa/mlx5: Fix erroneous null pointer checks

[Eli Cohen <eli@mellanox.com>]

After all this patch is not fixing it all. If we get to default of the switch statement we will free invalid pointer so removing ack-ed by me.

The previous patch by Colin King fixes it.


-----Original Message-----
From: Eli Cohen <eli@mellanox.com> 
Sent: Sunday, August 9, 2020 8:53 AM
To: Alex Dewar <alex.dewar90@gmail.com>
Cc: Michael S. Tsirkin <mst@redhat.com>; Jason Wang <jasowang@redhat.com>; Parav Pandit <parav@mellanox.com>; virtualization@lists.linux-foundation.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vdpa/mlx5: Fix erroneous null pointer checks

Acked-by: Eli Cohen <eli@mellanox.com>
On Thu, Aug 06, 2020 at 08:18:39PM +0100, Alex Dewar wrote:
> In alloc_inout() in net/mlx5_vnet.c, there are a few places where 
> memory is allocated to *in and *out, but only the values of in and out 
> are null-checked (i.e. there is a missing dereference). Fix this.
> 
> Addresses-Coverity: ("CID 1496603: (REVERSE_INULL)")
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 
> devices")
> Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c 
> b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 3ec44a4f0e45..bcb6600c2839 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -867,7 +867,7 @@ static void alloc_inout(struct mlx5_vdpa_net *ndev, int cmd, void **in, int *inl
>  		*outlen = MLX5_ST_SZ_BYTES(qp_2rst_out);
>  		*in = kzalloc(*inlen, GFP_KERNEL);
>  		*out = kzalloc(*outlen, GFP_KERNEL);
> -		if (!in || !out)
> +		if (!*in || !*out)
>  			goto outerr;
>  
>  		MLX5_SET(qp_2rst_in, *in, opcode, cmd); @@ -879,7 +879,7 @@ static 
> void alloc_inout(struct mlx5_vdpa_net *ndev, int cmd, void **in, int *inl
>  		*outlen = MLX5_ST_SZ_BYTES(rst2init_qp_out);
>  		*in = kzalloc(*inlen, GFP_KERNEL);
>  		*out = kzalloc(MLX5_ST_SZ_BYTES(rst2init_qp_out), GFP_KERNEL);
> -		if (!in || !out)
> +		if (!*in || !*out)
>  			goto outerr;
>  
>  		MLX5_SET(rst2init_qp_in, *in, opcode, cmd); @@ -896,7 +896,7 @@ 
> static void alloc_inout(struct mlx5_vdpa_net *ndev, int cmd, void **in, int *inl
>  		*outlen = MLX5_ST_SZ_BYTES(init2rtr_qp_out);
>  		*in = kzalloc(*inlen, GFP_KERNEL);
>  		*out = kzalloc(MLX5_ST_SZ_BYTES(init2rtr_qp_out), GFP_KERNEL);
> -		if (!in || !out)
> +		if (!*in || !*out)
>  			goto outerr;
>  
>  		MLX5_SET(init2rtr_qp_in, *in, opcode, cmd); @@ -914,7 +914,7 @@ 
> static void alloc_inout(struct mlx5_vdpa_net *ndev, int cmd, void **in, int *inl
>  		*outlen = MLX5_ST_SZ_BYTES(rtr2rts_qp_out);
>  		*in = kzalloc(*inlen, GFP_KERNEL);
>  		*out = kzalloc(MLX5_ST_SZ_BYTES(rtr2rts_qp_out), GFP_KERNEL);
> -		if (!in || !out)
> +		if (!*in || !*out)
>  			goto outerr;
>  
>  		MLX5_SET(rtr2rts_qp_in, *in, opcode, cmd);
> --
> 2.28.0
>