vlan: Fix register_vlan_dev() error path

In case register_netdevice() returns an error, and a new vlan_group
was allocated and inserted in vlan_group_hash[] we call
vlan_group_free() without deleting group from hash table. Future
lookups can give infinite loops or crashes.

We must delete the vlan_group using RCU safe procedure.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index 8836575f9d79..a29c5ab5815c 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -281,8 +281,11 @@ out_uninit_applicant:
         if (ngrp)
                 vlan_gvrp_uninit_applicant(real_dev);
 out_free_group:
-        if (ngrp)
-                vlan_group_free(ngrp);
+        if (ngrp) {
+                hlist_del_rcu(&ngrp->hlist);
+                /* Free the group, after all cpu's are done. */
+                call_rcu(&ngrp->rcu, vlan_rcu_free);
+        }
         return err;
 }