batman-adv: protect each hash row with rcu locks

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

8 files changed, 141 insertions, 45 deletions

diff --git a/net/batman-adv/hash.c b/net/batman-adv/hash.c
index fa2693973ab8..02653666a26b 100644
--- a/net/batman-adv/hash.c
+++ b/net/batman-adv/hash.c
@@ -27,13 +27,16 @@ static void hash_init(struct hashtable_t *hash)
 {
         int i;
 
-        for (i = 0 ; i < hash->size; i++)
+        for (i = 0 ; i < hash->size; i++) {
                 INIT_HLIST_HEAD(&hash->table[i]);
+                spin_lock_init(&hash->list_locks[i]);
+        }
 }
 
 /* free only the hashtable and the hash itself. */
 void hash_destroy(struct hashtable_t *hash)
 {
+        kfree(hash->list_locks);
         kfree(hash->table);
         kfree(hash);
 }
@@ -43,20 +46,33 @@ struct hashtable_t *hash_new(int size)
 {
         struct hashtable_t *hash;
 
-        hash = kmalloc(sizeof(struct hashtable_t) , GFP_ATOMIC);
-
+        hash = kmalloc(sizeof(struct hashtable_t), GFP_ATOMIC);
         if (!hash)
                 return NULL;
 
-        hash->size = size;
         hash->table = kmalloc(sizeof(struct element_t *) * size, GFP_ATOMIC);
+        if (!hash->table)
+                goto free_hash;
 
-        if (!hash->table) {
-                kfree(hash);
-                return NULL;
-        }
+        hash->list_locks = kmalloc(sizeof(spinlock_t) * size, GFP_ATOMIC);
+        if (!hash->list_locks)
+                goto free_table;
 
+        hash->size = size;
         hash_init(hash);
-
         return hash;
+
+free_table:
+        kfree(hash->table);
+free_hash:
+        kfree(hash);
+        return NULL;
+}
+
+void bucket_free_rcu(struct rcu_head *rcu)
+{
+        struct element_t *bucket;
+
+        bucket = container_of(rcu, struct element_t, rcu);
+        kfree(bucket);
 }
diff --git a/net/batman-adv/hash.h b/net/batman-adv/hash.h
index eae24402fd0a..3c48c6bb1acd 100644
--- a/net/batman-adv/hash.h
+++ b/net/batman-adv/hash.h
@@ -39,10 +39,12 @@ typedef void (*hashdata_free_cb)(void *, void *);
 struct element_t {
         void *data;             /* pointer to the data */
         struct hlist_node hlist;        /* bucket list pointer */
+        struct rcu_head rcu;
 };
 
 struct hashtable_t {
-        struct hlist_head *table;   /* the hashtable itself, with the buckets */
+        struct hlist_head *table;   /* the hashtable itself with the buckets */
+        spinlock_t *list_locks;     /* spinlock for each hash list entry */
         int size;                   /* size of hashtable */
 };
 
@@ -52,6 +54,8 @@ struct hashtable_t *hash_new(int size);
 /* free only the hashtable and the hash itself. */
 void hash_destroy(struct hashtable_t *hash);
 
+void bucket_free_rcu(struct rcu_head *rcu);
+
 /* remove the hash structure. if hashdata_free_cb != NULL, this function will be
  * called to remove the elements inside of the hash.  if you don't remove the
  * elements, memory might be leaked. */
@@ -61,19 +65,22 @@ static inline void hash_delete(struct hashtable_t *hash,
         struct hlist_head *head;
         struct hlist_node *walk, *safe;
         struct element_t *bucket;
+        spinlock_t *list_lock; /* spinlock to protect write access */
         int i;
 
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
+                list_lock = &hash->list_locks[i];
 
-                hlist_for_each_safe(walk, safe, head) {
-                        bucket = hlist_entry(walk, struct element_t, hlist);
+                spin_lock_bh(list_lock);
+                hlist_for_each_entry_safe(bucket, walk, safe, head, hlist) {
                         if (free_cb)
                                 free_cb(bucket->data, arg);
 
-                        hlist_del(walk);
-                        kfree(bucket);
+                        hlist_del_rcu(walk);
+                        call_rcu(&bucket->rcu, bucket_free_rcu);
                 }
+                spin_unlock_bh(list_lock);
         }
 
         hash_destroy(hash);
@@ -88,29 +95,39 @@ static inline int hash_add(struct hashtable_t *hash,
         struct hlist_head *head;
         struct hlist_node *walk, *safe;
         struct element_t *bucket;
+        spinlock_t *list_lock; /* spinlock to protect write access */
 
         if (!hash)
-                return -1;
+                goto err;
 
         index = choose(data, hash->size);
         head = &hash->table[index];
+        list_lock = &hash->list_locks[index];
 
-        hlist_for_each_safe(walk, safe, head) {
-                bucket = hlist_entry(walk, struct element_t, hlist);
+        rcu_read_lock();
+        hlist_for_each_entry_safe(bucket, walk, safe, head, hlist) {
                 if (compare(bucket->data, data))
-                        return -1;
+                        goto err_unlock;
         }
+        rcu_read_unlock();
 
         /* no duplicate found in list, add new element */
         bucket = kmalloc(sizeof(struct element_t), GFP_ATOMIC);
-
         if (!bucket)
-                return -1;
+                goto err;
 
         bucket->data = data;
-        hlist_add_head(&bucket->hlist, head);
+
+        spin_lock_bh(list_lock);
+        hlist_add_head_rcu(&bucket->hlist, head);
+        spin_unlock_bh(list_lock);
 
         return 0;
+
+err_unlock:
+        rcu_read_unlock();
+err:
+        return -1;
 }
 
 /* removes data from hash, if found. returns pointer do data on success, so you
@@ -125,25 +142,31 @@ static inline void *hash_remove(struct hashtable_t *hash,
         struct hlist_node *walk;
         struct element_t *bucket;
         struct hlist_head *head;
-        void *data_save;
+        void *data_save = NULL;
 
         index = choose(data, hash->size);
         head = &hash->table[index];
 
+        spin_lock_bh(&hash->list_locks[index]);
         hlist_for_each_entry(bucket, walk, head, hlist) {
                 if (compare(bucket->data, data)) {
                         data_save = bucket->data;
-                        hlist_del(walk);
-                        kfree(bucket);
-                        return data_save;
+                        hlist_del_rcu(walk);
+                        call_rcu(&bucket->rcu, bucket_free_rcu);
+                        break;
                 }
         }
+        spin_unlock_bh(&hash->list_locks[index]);
 
-        return NULL;
+        return data_save;
 }
 
-/* finds data, based on the key in keydata. returns the found data on success,
- * or NULL on error */
+/**
+ * finds data, based on the key in keydata. returns the found data on success,
+ * or NULL on error
+ *
+ * caller must lock with rcu_read_lock() / rcu_read_unlock()
+ **/
 static inline void *hash_find(struct hashtable_t *hash,
                               hashdata_compare_cb compare,
                               hashdata_choose_cb choose, void *keydata)
@@ -152,6 +175,7 @@ static inline void *hash_find(struct hashtable_t *hash,
         struct hlist_head *head;
         struct hlist_node *walk;
         struct element_t *bucket;
+        void *bucket_data = NULL;
 
         if (!hash)
                 return NULL;
@@ -159,13 +183,14 @@ static inline void *hash_find(struct hashtable_t *hash,
         index = choose(keydata , hash->size);
         head = &hash->table[index];
 
-        hlist_for_each(walk, head) {
-                bucket = hlist_entry(walk, struct element_t, hlist);
-                if (compare(bucket->data, keydata))
-                        return bucket->data;
+        hlist_for_each_entry(bucket, walk, head, hlist) {
+                if (compare(bucket->data, keydata)) {
+                        bucket_data = bucket->data;
+                        break;
+                }
         }
 
-        return NULL;
+        return bucket_data;
 }
 
 #endif /* _NET_BATMAN_ADV_HASH_H_ */
diff --git a/net/batman-adv/icmp_socket.c b/net/batman-adv/icmp_socket.c
index 319a7ccf6efa..8e0cd8a1bc02 100644
--- a/net/batman-adv/icmp_socket.c
+++ b/net/batman-adv/icmp_socket.c
@@ -220,9 +220,11 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff,
                 goto dst_unreach;
 
         spin_lock_bh(&bat_priv->orig_hash_lock);
+        rcu_read_lock();
         orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
                                                    compare_orig, choose_orig,
                                                    icmp_packet->dst));
+        rcu_read_unlock();
 
         if (!orig_node)
                 goto unlock;
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 899d4943d8ad..5c32314f8279 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -150,9 +150,11 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr)
         int size;
         int hash_added;
 
+        rcu_read_lock();
         orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
                                                    compare_orig, choose_orig,
                                                    addr));
+        rcu_read_unlock();
 
         if (orig_node)
                 return orig_node;
@@ -294,6 +296,7 @@ static void _purge_orig(struct bat_priv *bat_priv)
         struct hlist_node *walk, *safe;
         struct hlist_head *head;
         struct element_t *bucket;
+        spinlock_t *list_lock; /* spinlock to protect write access */
         struct orig_node *orig_node;
         int i;
 
@@ -305,22 +308,26 @@ static void _purge_orig(struct bat_priv *bat_priv)
         /* for all origins... */
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
+                list_lock = &hash->list_locks[i];
 
+                spin_lock_bh(list_lock);
                 hlist_for_each_entry_safe(bucket, walk, safe, head, hlist) {
                         orig_node = bucket->data;
 
                         if (purge_orig_node(bat_priv, orig_node)) {
                                 if (orig_node->gw_flags)
                                         gw_node_delete(bat_priv, orig_node);
-                                hlist_del(walk);
-                                kfree(bucket);
+                                hlist_del_rcu(walk);
+                                call_rcu(&bucket->rcu, bucket_free_rcu);
                                 free_orig_node(orig_node, bat_priv);
+                                continue;
                         }
 
                         if (time_after(jiffies, orig_node->last_frag_packet +
                                                 msecs_to_jiffies(FRAG_TIMEOUT)))
                                 frag_list_free(&orig_node->frag_list);
                 }
+                spin_unlock_bh(list_lock);
         }
 
         spin_unlock_bh(&bat_priv->orig_hash_lock);
@@ -387,7 +394,8 @@ int orig_seq_print_text(struct seq_file *seq, void *offset)
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
 
-                hlist_for_each_entry(bucket, walk, head, hlist) {
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
                         orig_node = bucket->data;
 
                         if (!orig_node->router)
@@ -408,17 +416,16 @@ int orig_seq_print_text(struct seq_file *seq, void *offset)
                                    neigh_node->addr,
                                    neigh_node->if_incoming->net_dev->name);
 
-                        rcu_read_lock();
                         hlist_for_each_entry_rcu(neigh_node, node,
                                                  &orig_node->neigh_list, list) {
                                 seq_printf(seq, " %pM (%3i)", neigh_node->addr,
                                                 neigh_node->tq_avg);
                         }
-                        rcu_read_unlock();
 
                         seq_printf(seq, "\n");
                         batman_count++;
                 }
+                rcu_read_unlock();
         }
 
         spin_unlock_bh(&bat_priv->orig_hash_lock);
@@ -476,18 +483,21 @@ int orig_hash_add_if(struct batman_if *batman_if, int max_if_num)
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
 
-                hlist_for_each_entry(bucket, walk, head, hlist) {
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
                         orig_node = bucket->data;
 
                         if (orig_node_add_if(orig_node, max_if_num) == -1)
                                 goto err;
                 }
+                rcu_read_unlock();
         }
 
         spin_unlock_bh(&bat_priv->orig_hash_lock);
         return 0;
 
 err:
+        rcu_read_unlock();
         spin_unlock_bh(&bat_priv->orig_hash_lock);
         return -ENOMEM;
 }
@@ -562,7 +572,8 @@ int orig_hash_del_if(struct batman_if *batman_if, int max_if_num)
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
 
-                hlist_for_each_entry(bucket, walk, head, hlist) {
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
                         orig_node = bucket->data;
 
                         ret = orig_node_del_if(orig_node, max_if_num,
@@ -571,6 +582,7 @@ int orig_hash_del_if(struct batman_if *batman_if, int max_if_num)
                         if (ret == -1)
                                 goto err;
                 }
+                rcu_read_unlock();
         }
 
         /* renumber remaining batman interfaces _inside_ of orig_hash_lock */
@@ -595,6 +607,7 @@ int orig_hash_del_if(struct batman_if *batman_if, int max_if_num)
         return 0;
 
 err:
+        rcu_read_unlock();
         spin_unlock_bh(&bat_priv->orig_hash_lock);
         return -ENOMEM;
 }
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index c15e6c1c20b5..32ae04e26a05 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -52,7 +52,8 @@ void slide_own_bcast_window(struct batman_if *batman_if)
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
 
-                hlist_for_each_entry(bucket, walk, head, hlist) {
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
                         orig_node = bucket->data;
                         word_index = batman_if->if_num * NUM_WORDS;
                         word = &(orig_node->bcast_own[word_index]);
@@ -61,6 +62,7 @@ void slide_own_bcast_window(struct batman_if *batman_if)
                         orig_node->bcast_own_sum[batman_if->if_num] =
                                 bit_packet_count(word);
                 }
+                rcu_read_unlock();
         }
 
         spin_unlock_bh(&bat_priv->orig_hash_lock);
@@ -873,9 +875,11 @@ static int recv_my_icmp_packet(struct bat_priv *bat_priv,
         /* answer echo request (ping) */
         /* get routing information */
         spin_lock_bh(&bat_priv->orig_hash_lock);
+        rcu_read_lock();
         orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
                                                    compare_orig, choose_orig,
                                                    icmp_packet->orig));
+        rcu_read_unlock();
         ret = NET_RX_DROP;
 
         if ((orig_node) && (orig_node->router)) {
@@ -931,9 +935,11 @@ static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv,
 
         /* get routing information */
         spin_lock_bh(&bat_priv->orig_hash_lock);
+        rcu_read_lock();
         orig_node = ((struct orig_node *)
                      hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                                icmp_packet->orig));
+        rcu_read_unlock();
         ret = NET_RX_DROP;
 
         if ((orig_node) && (orig_node->router)) {
@@ -1023,9 +1029,11 @@ int recv_icmp_packet(struct sk_buff *skb, struct batman_if *recv_if)
 
         /* get routing information */
         spin_lock_bh(&bat_priv->orig_hash_lock);
+        rcu_read_lock();
         orig_node = ((struct orig_node *)
                      hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                                icmp_packet->dst));
+        rcu_read_unlock();
 
         if ((orig_node) && (orig_node->router)) {
 
@@ -1094,9 +1102,11 @@ struct neigh_node *find_router(struct bat_priv *bat_priv,
                                 router_orig->orig, ETH_ALEN) == 0) {
                 primary_orig_node = router_orig;
         } else {
+                rcu_read_lock();
                 primary_orig_node = hash_find(bat_priv->orig_hash, compare_orig,
                                                choose_orig,
                                                router_orig->primary_addr);
+                rcu_read_unlock();
 
                 if (!primary_orig_node)
                         return orig_node->router;
@@ -1199,9 +1209,11 @@ int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,
 
         /* get routing information */
         spin_lock_bh(&bat_priv->orig_hash_lock);
+        rcu_read_lock();
         orig_node = ((struct orig_node *)
                      hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                                unicast_packet->dest));
+        rcu_read_unlock();
 
         router = find_router(bat_priv, orig_node, recv_if);
 
@@ -1345,9 +1357,11 @@ int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if)
                 return NET_RX_DROP;
 
         spin_lock_bh(&bat_priv->orig_hash_lock);
+        rcu_read_lock();
         orig_node = ((struct orig_node *)
                      hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                                bcast_packet->orig));
+        rcu_read_unlock();
 
         if (!orig_node) {
                 spin_unlock_bh(&bat_priv->orig_hash_lock);
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 7fb6726ccbdd..b25e4b328dcb 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -60,10 +60,12 @@ void hna_local_add(struct net_device *soft_iface, uint8_t *addr)
         int required_bytes;
 
         spin_lock_bh(&bat_priv->hna_lhash_lock);
+        rcu_read_lock();
         hna_local_entry =
                 ((struct hna_local_entry *)hash_find(bat_priv->hna_local_hash,
                                                      compare_orig, choose_orig,
                                                      addr));
+        rcu_read_unlock();
         spin_unlock_bh(&bat_priv->hna_lhash_lock);
 
         if (hna_local_entry) {
@@ -116,9 +118,11 @@ void hna_local_add(struct net_device *soft_iface, uint8_t *addr)
         /* remove address from global hash if present */
         spin_lock_bh(&bat_priv->hna_ghash_lock);
 
+        rcu_read_lock();
         hna_global_entry = ((struct hna_global_entry *)
                                 hash_find(bat_priv->hna_global_hash,
                                           compare_orig, choose_orig, addr));
+        rcu_read_unlock();
 
         if (hna_global_entry)
                 _hna_global_del_orig(bat_priv, hna_global_entry,
@@ -252,9 +256,11 @@ void hna_local_remove(struct bat_priv *bat_priv,
 
         spin_lock_bh(&bat_priv->hna_lhash_lock);
 
+        rcu_read_lock();
         hna_local_entry = (struct hna_local_entry *)
                 hash_find(bat_priv->hna_local_hash, compare_orig, choose_orig,
                           addr);
+        rcu_read_unlock();
 
         if (hna_local_entry)
                 hna_local_del(bat_priv, hna_local_entry, message);
@@ -334,9 +340,11 @@ void hna_global_add_orig(struct bat_priv *bat_priv,
                 spin_lock_bh(&bat_priv->hna_ghash_lock);
 
                 hna_ptr = hna_buff + (hna_buff_count * ETH_ALEN);
+                rcu_read_lock();
                 hna_global_entry = (struct hna_global_entry *)
                         hash_find(bat_priv->hna_global_hash, compare_orig,
                                   choose_orig, hna_ptr);
+                rcu_read_unlock();
 
                 if (!hna_global_entry) {
                         spin_unlock_bh(&bat_priv->hna_ghash_lock);
@@ -368,9 +376,11 @@ void hna_global_add_orig(struct bat_priv *bat_priv,
                 spin_lock_bh(&bat_priv->hna_lhash_lock);
 
                 hna_ptr = hna_buff + (hna_buff_count * ETH_ALEN);
+                rcu_read_lock();
                 hna_local_entry = (struct hna_local_entry *)
                         hash_find(bat_priv->hna_local_hash, compare_orig,
                                   choose_orig, hna_ptr);
+                rcu_read_unlock();
 
                 if (hna_local_entry)
                         hna_local_del(bat_priv, hna_local_entry,
@@ -483,9 +493,11 @@ void hna_global_del_orig(struct bat_priv *bat_priv,
 
         while ((hna_buff_count + 1) * ETH_ALEN <= orig_node->hna_buff_len) {
                 hna_ptr = orig_node->hna_buff + (hna_buff_count * ETH_ALEN);
+                rcu_read_lock();
                 hna_global_entry = (struct hna_global_entry *)
                         hash_find(bat_priv->hna_global_hash, compare_orig,
                                   choose_orig, hna_ptr);
+                rcu_read_unlock();
 
                 if ((hna_global_entry) &&
                     (hna_global_entry->orig_node == orig_node))
@@ -521,9 +533,11 @@ struct orig_node *transtable_search(struct bat_priv *bat_priv, uint8_t *addr)
         struct hna_global_entry *hna_global_entry;
 
         spin_lock_bh(&bat_priv->hna_ghash_lock);
+        rcu_read_lock();
         hna_global_entry = (struct hna_global_entry *)
                                 hash_find(bat_priv->hna_global_hash,
                                           compare_orig, choose_orig, addr);
+        rcu_read_unlock();
         spin_unlock_bh(&bat_priv->hna_ghash_lock);
 
         if (!hna_global_entry)
diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
index 1b5e761d8823..4687027f1495 100644
--- a/net/batman-adv/unicast.c
+++ b/net/batman-adv/unicast.c
@@ -179,9 +179,11 @@ int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
 
         *new_skb = NULL;
         spin_lock_bh(&bat_priv->orig_hash_lock);
+        rcu_read_lock();
         orig_node = ((struct orig_node *)
                     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
                               unicast_packet->orig));
+        rcu_read_unlock();
 
         if (!orig_node) {
                 pr_debug("couldn't find originator in orig_hash\n");
diff --git a/net/batman-adv/vis.c b/net/batman-adv/vis.c
index a77b773b0868..8092eadcbdee 100644
--- a/net/batman-adv/vis.c
+++ b/net/batman-adv/vis.c
@@ -380,8 +380,10 @@ static struct vis_info *add_packet(struct bat_priv *bat_priv,
                                                      sizeof(struct vis_packet));
 
         memcpy(search_packet->vis_orig, vis_packet->vis_orig, ETH_ALEN);
+        rcu_read_lock();
         old_info = hash_find(bat_priv->vis_hash, vis_info_cmp, vis_info_choose,
                              &search_elem);
+        rcu_read_unlock();
         kfree_skb(search_elem.skb_packet);
 
         if (old_info) {
@@ -540,7 +542,8 @@ static int find_best_vis_server(struct bat_priv *bat_priv,
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
 
-                hlist_for_each_entry(bucket, walk, head, hlist) {
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
                         orig_node = bucket->data;
                         if ((orig_node) && (orig_node->router) &&
                         (orig_node->flags & VIS_SERVER) &&
@@ -550,6 +553,7 @@ static int find_best_vis_server(struct bat_priv *bat_priv,
                                        ETH_ALEN);
                         }
                 }
+                rcu_read_unlock();
         }
 
         return best_tq;
@@ -605,7 +609,8 @@ static int generate_vis_packet(struct bat_priv *bat_priv)
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
 
-                hlist_for_each_entry(bucket, walk, head, hlist) {
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
                         orig_node = bucket->data;
                         neigh_node = orig_node->router;
 
@@ -632,10 +637,12 @@ static int generate_vis_packet(struct bat_priv *bat_priv)
                         packet->entries++;
 
                         if (vis_packet_full(info)) {
+                                rcu_read_unlock();
                                 spin_unlock_bh(&bat_priv->orig_hash_lock);
                                 return 0;
                         }
                 }
+                rcu_read_unlock();
         }
 
         spin_unlock_bh(&bat_priv->orig_hash_lock);
@@ -721,7 +728,8 @@ static void broadcast_vis_packet(struct bat_priv *bat_priv,
         for (i = 0; i < hash->size; i++) {
                 head = &hash->table[i];
 
-                hlist_for_each_entry(bucket, walk, head, hlist) {
+                rcu_read_lock();
+                hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
                         orig_node = bucket->data;
 
                         /* if it's a vis server and reachable, send it. */
@@ -746,7 +754,7 @@ static void broadcast_vis_packet(struct bat_priv *bat_priv,
 
                         spin_lock_bh(&bat_priv->orig_hash_lock);
                 }
-
+                rcu_read_unlock();
         }
 
         spin_unlock_bh(&bat_priv->orig_hash_lock);
@@ -763,9 +771,11 @@ static void unicast_vis_packet(struct bat_priv *bat_priv,
 
         spin_lock_bh(&bat_priv->orig_hash_lock);
         packet = (struct vis_packet *)info->skb_packet->data;
+        rcu_read_lock();
         orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
                                                    compare_orig, choose_orig,
                                                    packet->target_orig));
+        rcu_read_unlock();
 
         if ((!orig_node) || (!orig_node->router))
                 goto out;