RE: [Intel-wired-lan] [PATCH iwl-net v1] i40e: Fix macvlan leak by synchronizing access to mac_filter_hash

-----Original Message-----
From: Intel-wired-lan <redacted> On Behalf Of Simon
Horman
Sent: Tuesday, September 24, 2024 8:57 AM
To: Loktionov, Aleksandr <redacted>
Cc: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kubalewski, Arkadiusz
[off-list ref]; intel-wired-lan@lists.osuosl.org;
netdev@vger.kernel.org
Subject: Re: [Intel-wired-lan] [PATCH iwl-net v1] i40e: Fix macvlan leak by
synchronizing access to mac_filter_hash

On Mon, Sep 23, 2024 at 11:12:19AM +0200, Aleksandr Loktionov wrote:

quoted

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
vf->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.

Fixes: fed0d9f13266 ("i40e: Fix VF's MAC Address change on VM")
Reviewed-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Signed-off-by: Aleksandr Loktionov <redacted>

Thanks Aleksandr,

I see that:

1) All calls to i40e_add_mac_filter() and all other calls
   to i40e_del_mac_filter() are already protected by
   vsi->mac_filter_hash_lock.

2) i40e_del_mac_filter() already asserts that
   vsi->mac_filter_hash_lock is held.

So this looks good to me.

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

...

Tested-by: Rafal Romanowski <redacted>