Subject: Re: [PATCH net] ixgbe: fix crash with empty VF macvlan list

From: Simon Horman <[email-masked]>
Date: Fri, 6 Oct 2023 13:16:27 +0200

On Thu, Oct 05, 2023 at 04:57:02PM +0300, Dan Carpenter wrote:
> The adapter->vf_mvs.l list needs to be initialized even if the list is
> empty.  Otherwise it will lead to crashes.
> 
> Fixes: c6bda30a06d9 ("ixgbe: Reconfigure SR-IOV Init")

Hi Dan,

I see that the patch cited above added the line you are changing.
But it also seems to me that patch was moving it from elsewhere.

Perhaps I am mistaken, but I wonder if this is a better tag.

Fixes: a1cbb15c1397 ("ixgbe: Add macvlan support for VF")

> Signed-off-by: Dan Carpenter <[email-masked]>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
> index a703ba975205..9cfdfa8a4355 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
> @@ -28,6 +28,9 @@ static inline void ixgbe_alloc_vf_macvlans(struct ixgbe_adapter *adapter,
>  	struct vf_macvlans *mv_list;
>  	int num_vf_macvlans, i;
>  
> +	/* Initialize list of VF macvlans */
> +	INIT_LIST_HEAD(&adapter->vf_mvs.l);
> +
>  	num_vf_macvlans = hw->mac.num_rar_entries -
>  			  (IXGBE_MAX_PF_MACVLANS + 1 + num_vfs);
>  	if (!num_vf_macvlans)
> @@ -36,8 +39,6 @@ static inline void ixgbe_alloc_vf_macvlans(struct ixgbe_adapter *adapter,
>  	mv_list = kcalloc(num_vf_macvlans, sizeof(struct vf_macvlans),
>  			  GFP_KERNEL);
>  	if (mv_list) {

I'm not sure it it is worth it, but perhaps more conventional error
handling could be used here:

	if (!mv_list)
		return;

	for (i = 0; i < num_vf_macvlans; i++) {
		...

> -		/* Initialize list of VF macvlans */
> -		INIT_LIST_HEAD(&adapter->vf_mvs.l);
>  		for (i = 0; i < num_vf_macvlans; i++) {
>  			mv_list[i].vf = -1;
>  			mv_list[i].free = true;
> -- 
> 2.39.2
> 
>