[PATCH] net/mlx4_core: Adjust allocation type for buddy->bits

[PATCH] net/mlx4_core: Adjust allocation type for buddy->bits

[Kees Cook]

In preparation for making the kmalloc family of allocators type aware,
we need to make sure that the returned type from the allocation matches
the type of the variable being assigned. (Before, the allocator would
always return "void *", which can be implicitly cast to any pointer type.)

The assigned type is "unsigned long **", but the returned type will be
"long **". These are the same size allocation (pointer size) but the
types do not match. Adjust the allocation type to match the assignment.

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Tariq Toukan <tariqt@nvidia.com>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: <netdev@vger.kernel.org>
Cc: <linux-rdma@vger.kernel.org>
---
 drivers/net/ethernet/mellanox/mlx4/mr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/mr.c b/drivers/net/ethernet/mellanox/mlx4/mr.c
index d7444782bfdd..698a5d1f0d7e 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mr.c
+++ b/drivers/net/ethernet/mellanox/mlx4/mr.c
@@ -106,7 +106,7 @@ static int mlx4_buddy_init(struct mlx4_buddy *buddy, int max_order)
 	buddy->max_order = max_order;
 	spin_lock_init(&buddy->lock);
 
-	buddy->bits = kcalloc(buddy->max_order + 1, sizeof(long *),
+	buddy->bits = kcalloc(buddy->max_order + 1, sizeof(*buddy->bits),
 			      GFP_KERNEL);
 	buddy->num_free = kcalloc(buddy->max_order + 1, sizeof(*buddy->num_free),
 				  GFP_KERNEL);
-- 
2.34.1

Re: [PATCH] net/mlx4_core: Adjust allocation type for buddy->bits

[Simon Horman]

On Fri, Apr 25, 2025 at 11:07:58PM -0700, Kees Cook wrote:
> In preparation for making the kmalloc family of allocators type aware,
> we need to make sure that the returned type from the allocation matches
> the type of the variable being assigned. (Before, the allocator would
> always return "void *", which can be implicitly cast to any pointer type.)
> 
> The assigned type is "unsigned long **", but the returned type will be
> "long **". These are the same size allocation (pointer size) but the
> types do not match. Adjust the allocation type to match the assignment.
> 
> Signed-off-by: Kees Cook <kees@kernel.org>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH] net/mlx4_core: Adjust allocation type for buddy->bits

[Tariq Toukan]

On 26/04/2025 9:07, Kees Cook wrote:
> In preparation for making the kmalloc family of allocators type aware,
> we need to make sure that the returned type from the allocation matches
> the type of the variable being assigned. (Before, the allocator would
> always return "void *", which can be implicitly cast to any pointer type.)
> 
> The assigned type is "unsigned long **", but the returned type will be
> "long **". These are the same size allocation (pointer size) but the
> types do not match. Adjust the allocation type to match the assignment.
> 
> Signed-off-by: Kees Cook <kees@kernel.org>
> ---
> Cc: Tariq Toukan <tariqt@nvidia.com>
> Cc: Andrew Lunn <andrew+netdev@lunn.ch>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: <netdev@vger.kernel.org>
> Cc: <linux-rdma@vger.kernel.org>
> ---
>   drivers/net/ethernet/mellanox/mlx4/mr.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/mr.c b/drivers/net/ethernet/mellanox/mlx4/mr.c
> index d7444782bfdd..698a5d1f0d7e 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/mr.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/mr.c
> @@ -106,7 +106,7 @@ static int mlx4_buddy_init(struct mlx4_buddy *buddy, int max_order)
>   	buddy->max_order = max_order;
>   	spin_lock_init(&buddy->lock);
>   
> -	buddy->bits = kcalloc(buddy->max_order + 1, sizeof(long *),
> +	buddy->bits = kcalloc(buddy->max_order + 1, sizeof(*buddy->bits),
>   			      GFP_KERNEL);
>   	buddy->num_free = kcalloc(buddy->max_order + 1, sizeof(*buddy->num_free),
>   				  GFP_KERNEL);

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>

Thanks.

Re: [PATCH] net/mlx4_core: Adjust allocation type for buddy->bits

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 25 Apr 2025 23:07:58 -0700 you wrote:
> In preparation for making the kmalloc family of allocators type aware,
> we need to make sure that the returned type from the allocation matches
> the type of the variable being assigned. (Before, the allocator would
> always return "void *", which can be implicitly cast to any pointer type.)
> 
> The assigned type is "unsigned long **", but the returned type will be
> "long **". These are the same size allocation (pointer size) but the
> types do not match. Adjust the allocation type to match the assignment.
> 
> [...]

Here is the summary with links:
  - net/mlx4_core: Adjust allocation type for buddy->bits
    https://git.kernel.org/netdev/net-next/c/01cbf838c775

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html