net: hsr: fix VLAN add unwind on slave errors

When vlan_vid_add() fails for a secondary slave, the error path calls
vlan_vid_del() on the failing port instead of the peer slave that had
already succeeded. This results in asymmetric VLAN state across the HSR
pair.

Fix this by switching to a centralized unwind path that removes the VID
from any slave device that was already programmed.

Fixes: 1a8a63a5305e ("net: hsr: Add VLAN CTAG filter support")
Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
Link: https://patch.msgid.link/20260401092243.52121-3-luka.gejak@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index d1bfc49b5f017bc7fbbdedcc1eeab4d7e95e56be..fd2fea25eff0ddae29528fe821b545e9d13d57b2 100644 (file)
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -532,8 +532,8 @@ static void hsr_change_rx_flags(struct net_device *dev, int change)
 static int hsr_ndo_vlan_rx_add_vid(struct net_device *dev,
                                   __be16 proto, u16 vid)
 {
-       bool is_slave_a_added = false;
-       bool is_slave_b_added = false;
+       struct net_device *slave_a_dev = NULL;
+       struct net_device *slave_b_dev = NULL;
        struct hsr_port *port;
        struct hsr_priv *hsr;
        int ret = 0;
@@ -549,33 +549,35 @@ static int hsr_ndo_vlan_rx_add_vid(struct net_device *dev,
                switch (port->type) {
                case HSR_PT_SLAVE_A:
                        if (ret) {
-                               /* clean up Slave-B */
                                netdev_err(dev, "add vid failed for Slave-A\n");
-                               if (is_slave_b_added)
-                                       vlan_vid_del(port->dev, proto, vid);
-                               return ret;
+                               goto unwind;
                        }
-
-                       is_slave_a_added = true;
+                       slave_a_dev = port->dev;
                        break;
-
                case HSR_PT_SLAVE_B:
                        if (ret) {
-                               /* clean up Slave-A */
                                netdev_err(dev, "add vid failed for Slave-B\n");
-                               if (is_slave_a_added)
-                                       vlan_vid_del(port->dev, proto, vid);
-                               return ret;
+                               goto unwind;
                        }
-
-                       is_slave_b_added = true;
+                       slave_b_dev = port->dev;
                        break;
                default:
+                       if (ret)
+                               goto unwind;
                        break;
                }
        }
 
        return 0;
+
+unwind:
+       if (slave_a_dev)
+               vlan_vid_del(slave_a_dev, proto, vid);
+
+       if (slave_b_dev)
+               vlan_vid_del(slave_b_dev, proto, vid);
+
+       return ret;
 }
 
 static int hsr_ndo_vlan_rx_kill_vid(struct net_device *dev,