Re: [PATCH net] net: hsr: fix memory leak on slave unregistration by removing synced VLANs
From: Felix Maurer <hidden>
Date: 2026-07-07 11:38:29
On Tue, Jul 07, 2026 at 08:23:27AM +0000, Eric Dumazet 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 (local)
Signed-off-by: Eric Dumazet <edumazet@google.com>Looks good to me, thank you! Reviewed-by: Felix Maurer <redacted>
quoted hunk ↗ jump to hunk
--- net/hsr/hsr_slave.c | 1 + 1 file changed, 1 insertion(+)diff --git a/net/hsr/hsr_slave.c b/net/hsr/hsr_slave.c index d9af9e65f72f07b1997b80c85db16d812fbda488..2d1e3ea72088e35d5d870b4cc86dd2f789670394 100644 --- a/net/hsr/hsr_slave.c +++ b/net/hsr/hsr_slave.c@@ -242,6 +242,7 @@ void hsr_del_port(struct hsr_port *port) netdev_rx_handler_unregister(port->dev); if (!port->hsr->fwd_offloaded) dev_set_promiscuity(port->dev, -1); + vlan_vids_del_by_dev(port->dev, master->dev); netdev_upper_dev_unlink(port->dev, master->dev); if (hsr->prot_version == PRP_V1 && port->type == HSR_PT_SLAVE_B) { --2.55.0.795.g602f6c329a-goog