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vxlan: few locking fixes in nexthop event handler 

- remove fdb from nh_list before the rcu grace period
- protect fdb->vdev with rcu
- hold spin lock before destroying fdb

Fixes: c7cdbe2efc ("vxlan: support for nexthop notifiers")
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Roopa Prabhu 2020-05-28 22:12:36 -07:00 committed by David S. Miller
parent 72b4868211
commit 79472fe873
1 changed files with 25 additions and 7 deletions
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32
drivers/net/vxlan.c
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@ -81,7 +81,7 @@ struct vxlan_fdb {
u16 flags; /* see ndm_flags and below */
struct list_head nh_list;
struct nexthop __rcu *nh;
struct vxlan_dev *vdev;
struct vxlan_dev __rcu *vdev;
};
#define NTF_VXLAN_ADDED_BY_USER 0x100
@ -837,7 +837,7 @@ static struct vxlan_fdb *vxlan_fdb_alloc(struct vxlan_dev *vxlan, const u8 *mac,
f->updated = f->used = jiffies;
f->vni = src_vni;
f->nh = NULL;
f->vdev = vxlan;
RCU_INIT_POINTER(f->vdev, vxlan);
INIT_LIST_HEAD(&f->nh_list);
INIT_LIST_HEAD(&f->remotes);
memcpy(f->eth_addr, mac, ETH_ALEN);
@ -963,7 +963,7 @@ static void __vxlan_fdb_free(struct vxlan_fdb *f)
nh = rcu_dereference_raw(f->nh);
if (nh) {
rcu_assign_pointer(f->nh, NULL);
list_del_rcu(&f->nh_list);
rcu_assign_pointer(f->vdev, NULL);
nexthop_put(nh);
}
@ -1000,7 +1000,7 @@ static void vxlan_fdb_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f,
}
hlist_del_rcu(&f->hlist);
f->vdev = NULL;
list_del_rcu(&f->nh_list);
call_rcu(&f->rcu, vxlan_fdb_free);
}
@ -4615,17 +4615,35 @@ static struct notifier_block vxlan_switchdev_notifier_block __read_mostly = {
.notifier_call = vxlan_switchdev_event,
};
static void vxlan_fdb_nh_flush(struct nexthop *nh)
{
struct vxlan_fdb *fdb;
struct vxlan_dev *vxlan;
u32 hash_index;
rcu_read_lock();
list_for_each_entry_rcu(fdb, &nh->fdb_list, nh_list) {
vxlan = rcu_dereference(fdb->vdev);
WARN_ON(!vxlan);
hash_index = fdb_head_index(vxlan, fdb->eth_addr,
vxlan->default_dst.remote_vni);
spin_lock_bh(&vxlan->hash_lock[hash_index]);
if (!hlist_unhashed(&fdb->hlist))
vxlan_fdb_destroy(vxlan, fdb, false, false);
spin_unlock_bh(&vxlan->hash_lock[hash_index]);
}
rcu_read_unlock();
}
static int vxlan_nexthop_event(struct notifier_block *nb,
unsigned long event, void *ptr)
{
struct nexthop *nh = ptr;
struct vxlan_fdb *fdb, *tmp;
if (!nh || event != NEXTHOP_EVENT_DEL)
return NOTIFY_DONE;
list_for_each_entry_safe(fdb, tmp, &nh->fdb_list, nh_list)
vxlan_fdb_destroy(fdb->vdev, fdb, false, false);
vxlan_fdb_nh_flush(nh);
return NOTIFY_DONE;
}