AZL-53954

In the Linux kernel, the following vulnerability has been resolved:

i40e: fix race condition by adding filter's intermediate sync state

Fix a race condition in the i40e driver that leads to MAC/VLAN filters becoming corrupted and leaking. Address the issue that occurs under heavy load when multiple threads are concurrently modifying MAC/VLAN filters by setting mac and port VLAN.

1. Thread T0 allocates a filter in i40e_add_filter() within i40e_ndo_set_vf_port_vlan().
2. Thread T1 concurrently frees the filter in __i40e_del_filter() within i40e_ndo_set_vf_mac().
3. Subsequently, i40e_service_task() calls i40e_sync_vsi_filters(), which refers to the already freed filter memory, causing corruption.

Reproduction steps:

1. Spawn multiple VFs.
2. Apply a concurrent heavy load by running parallel operations to change MAC addresses on the VFs and change port VLANs on the host.
3. Observe errors in dmesg: "Error I40E_AQ_RC_ENOSPC adding RX filters on VF XX, please set promiscuous on manually for VF XX".

Exact code for stable reproduction Intel can't open-source now.

The fix involves implementing a new intermediate filter state, I40E_FILTER_NEW_SYNC, for the time when a filter is on a tmp_add_list. These filters cannot be deleted from the hash list directly but must be removed using the full process.