CVE-2024-50041: Missing Release of Memory after Effective Lifetime

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

i40e: Fix macvlan leak by synchronizing access to mac_filter_hash

This patch addresses a macvlan leak issue in the i40e driver caused by concurrent access to vsi->mac_filter_hash. The leak occurs when multiple threads attempt to modify the mac_filter_hash simultaneously, leading to inconsistent state and potential memory leaks.

To fix this, we now wrap the calls to i40e_del_mac_filter() and zeroing vf->default_lan_addr.addr with spin_lock/unlock_bh(&vsi->mac_filter_hash_lock), ensuring atomic operations and preventing concurrent access.

Additionally, we add lockdep_assert_held(&vsi->mac_filter_hash_lock) in i40e_add_mac_filter() to help catch similar issues in the future.

Reproduction steps: 1. Spawn VFs and configure port vlan on them. 2. Trigger concurrent macvlan operations (e.g., adding and deleting portvlan and/or mac filters). 3. Observe the potential memory leak and inconsistent state in the mac_filter_hash.

This synchronization ensures the integrity of the mac_filter_hash and prevents the described leak.