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

[Jakub Kicinski <kuba@kernel.org>]

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