Re: [PATCH net] net: hsr: fix memory leak on slave unregistration by removing synced VLANs

[Paolo Abeni <pabeni@redhat.com>]

On 7/21/26 3:12 AM, Jakub Kicinski wrote:
> On Tue, 14 Jul 2026 22:45:24 +0200 Fernando Fernandez Mancera wrote:
>>> When an HSR master device is brought UP, it auto-adds VLAN 0 via
>>> vlan_vid0_add(), which propagates VID 0 to its slave devices.
>>>
>>> If a slave device is later unregistered while HSR is active (e.g., during
>>> netns cleanup or interface destruction), hsr_del_port() is called to
>>> detach the slave port from the HSR master. However, hsr_del_port() currently
>>> does not delete the VLAN IDs that were synced to the slave device by HSR.
>>>
>>> As a result, the slave device retains a refcount on VID 0 (and any other
>>> synced VLANs). When the slave device is destroyed, its vlan_info /
>>> vlan_vid_info structure remains allocated, leading to a memory leak.
>>>
>>> Fix this by calling vlan_vids_del_by_dev(port->dev, master->dev) in
>>> hsr_del_port() before unlinking the slave device, matching the cleanup
>>> behavior in bonding and team drivers.
>>>
>>> Fixes: 1a8a63a5305e ("net: hsr: Add VLAN CTAG filter support")
>>> Reported-by: syzbot+456957213f32970c0762@syzkaller.appspotmail.com
>>> Closes: https://lore.kernel.org/netdev/6a4cb6ca.57639fcc.86d58.000b.GAE@google.com/T/#u
>>> Signed-off-by: Eric Dumazet <edumazet@google.com>
>>
>> Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
> 
> Just to confirm - is the sashiko review a false positive?
> https://sashiko.dev/#/patchset/20260707082327.3238690-1-edumazet%40google.com

I'm sorry, meanwhile PW archived the patch; a repost is needed.

Thanks,

Paolo