diff --git a/src/http/modules/ngx_http_upstream_hash_module.c b/src/http/modules/ngx_http_upstream_hash_module.c
index 249733f72..56ec38ae0 100644
--- a/src/http/modules/ngx_http_upstream_hash_module.c
+++ b/src/http/modules/ngx_http_upstream_hash_module.c
@@ -176,7 +176,10 @@ ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data)
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                    "get hash peer, try: %ui", pc->tries);
 
+    ngx_http_upstream_rr_peers_wlock(hp->rrp.peers);
+
     if (hp->tries > 20 || hp->rrp.peers->single) {
+        ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
         return hp->get_rr_peer(pc, &hp->rrp);
     }
 
@@ -258,6 +261,7 @@ ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data)
     next:
 
         if (++hp->tries > 20) {
+            ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
             return hp->get_rr_peer(pc, &hp->rrp);
         }
     }
@@ -274,6 +278,8 @@ ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data)
         peer->checked = now;
     }
 
+    ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
+
     hp->rrp.tried[n] |= m;
 
     return NGX_OK;
@@ -465,8 +471,13 @@ ngx_http_upstream_init_chash_peer(ngx_http_request_t *r,
     hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module);
 
     hash = ngx_crc32_long(hp->key.data, hp->key.len);
+
+    ngx_http_upstream_rr_peers_rlock(hp->rrp.peers);
+
     hp->hash = ngx_http_upstream_find_chash_point(hcf->points, hash);
 
+    ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
+
     return NGX_OK;
 }
 
@@ -489,6 +500,8 @@ ngx_http_upstream_get_chash_peer(ngx_peer_connection_t *pc, void *data)
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                    "get consistent hash peer, try: %ui", pc->tries);
 
+    ngx_http_upstream_rr_peers_wlock(hp->rrp.peers);
+
     pc->cached = 0;
     pc->connection = NULL;
 
@@ -561,6 +574,7 @@ ngx_http_upstream_get_chash_peer(ngx_peer_connection_t *pc, void *data)
         hp->tries++;
 
         if (hp->tries >= points->number) {
+            ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
             return NGX_BUSY;
         }
     }
@@ -579,6 +593,8 @@ found:
         best->checked = now;
     }
 
+    ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
+
     n = best_i / (8 * sizeof(uintptr_t));
     m = (uintptr_t) 1 << best_i % (8 * sizeof(uintptr_t));
 
diff --git a/src/http/modules/ngx_http_upstream_ip_hash_module.c b/src/http/modules/ngx_http_upstream_ip_hash_module.c
index 2c6506d6f..debc0d8e5 100644
--- a/src/http/modules/ngx_http_upstream_ip_hash_module.c
+++ b/src/http/modules/ngx_http_upstream_ip_hash_module.c
@@ -161,7 +161,10 @@ ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
 
     /* TODO: cached */
 
+    ngx_http_upstream_rr_peers_wlock(iphp->rrp.peers);
+
     if (iphp->tries > 20 || iphp->rrp.peers->single) {
+        ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
         return iphp->get_rr_peer(pc, &iphp->rrp);
     }
 
@@ -212,8 +215,6 @@ ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
         ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                        "get ip hash peer, hash: %ui %04XA", p, m);
 
-        /* ngx_lock_mutex(iphp->rrp.peers->mutex); */
-
         if (peer->down) {
             goto next_try;
         }
@@ -230,14 +231,12 @@ ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
     next_try:
 
         iphp->rrp.tried[n] |= m;
-
-        /* ngx_unlock_mutex(iphp->rrp.peers->mutex); */
-
         pc->tries--;
 
     next:
 
         if (++iphp->tries > 20) {
+            ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
             return iphp->get_rr_peer(pc, &iphp->rrp);
         }
     }
@@ -254,7 +253,7 @@ ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
         peer->checked = now;
     }
 
-    /* ngx_unlock_mutex(iphp->rrp.peers->mutex); */
+    ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
 
     iphp->rrp.tried[n] |= m;
     iphp->hash = hash;
diff --git a/src/http/modules/ngx_http_upstream_least_conn_module.c b/src/http/modules/ngx_http_upstream_least_conn_module.c
index 61b538631..92951bd20 100644
--- a/src/http/modules/ngx_http_upstream_least_conn_module.c
+++ b/src/http/modules/ngx_http_upstream_least_conn_module.c
@@ -122,6 +122,8 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
 
     peers = rrp->peers;
 
+    ngx_http_upstream_rr_peers_wlock(peers);
+
     best = NULL;
     total = 0;
 
@@ -241,6 +243,8 @@ ngx_http_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
 
     rrp->tried[n] |= m;
 
+    ngx_http_upstream_rr_peers_unlock(peers);
+
     return NGX_OK;
 
 failed:
@@ -258,11 +262,15 @@ failed:
              rrp->tried[i] = 0;
         }
 
+        ngx_http_upstream_rr_peers_unlock(peers);
+
         rc = ngx_http_upstream_get_least_conn_peer(pc, rrp);
 
         if (rc != NGX_BUSY) {
             return rc;
         }
+
+        ngx_http_upstream_rr_peers_wlock(peers);
     }
 
     /* all peers failed, mark them as live for quick recovery */
@@ -271,6 +279,8 @@ failed:
         peer->fails = 0;
     }
 
+    ngx_http_upstream_rr_peers_unlock(peers);
+
     pc->name = peers->name;
 
     return NGX_BUSY;
diff --git a/src/http/ngx_http_upstream_round_robin.c b/src/http/ngx_http_upstream_round_robin.c
index 8d7046ade..9a970dcba 100644
--- a/src/http/ngx_http_upstream_round_robin.c
+++ b/src/http/ngx_http_upstream_round_robin.c
@@ -432,8 +432,7 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
     pc->connection = NULL;
 
     peers = rrp->peers;
-
-    /* ngx_lock_mutex(peers->mutex); */
+    ngx_http_upstream_rr_peers_wlock(peers);
 
     if (peers->single) {
         peer = peers->peer;
@@ -465,7 +464,7 @@ ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
 
     peer->conns++;
 
-    /* ngx_unlock_mutex(peers->mutex); */
+    ngx_http_upstream_rr_peers_unlock(peers);
 
     return NGX_OK;
 
@@ -473,8 +472,6 @@ failed:
 
     if (peers->next) {
 
-        /* ngx_unlock_mutex(peers->mutex); */
-
         ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0, "backup servers");
 
         rrp->peers = peers->next;
@@ -486,13 +483,15 @@ failed:
              rrp->tried[i] = 0;
         }
 
+        ngx_http_upstream_rr_peers_unlock(peers);
+
         rc = ngx_http_upstream_get_round_robin_peer(pc, rrp);
 
         if (rc != NGX_BUSY) {
             return rc;
         }
 
-        /* ngx_lock_mutex(peers->mutex); */
+        ngx_http_upstream_rr_peers_wlock(peers);
     }
 
     /* all peers failed, mark them as live for quick recovery */
@@ -501,7 +500,7 @@ failed:
         peer->fails = 0;
     }
 
-    /* ngx_unlock_mutex(peers->mutex); */
+    ngx_http_upstream_rr_peers_unlock(peers);
 
     pc->name = peers->name;
 
@@ -608,11 +607,12 @@ ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
         return;
     }
 
+    ngx_http_upstream_rr_peers_rlock(rrp->peers);
+    ngx_http_upstream_rr_peer_lock(rrp->peers, peer);
+
     if (state & NGX_PEER_FAILED) {
         now = ngx_time();
 
-        /* ngx_lock_mutex(rrp->peers->mutex); */
-
         peer->fails++;
         peer->accessed = now;
         peer->checked = now;
@@ -629,8 +629,6 @@ ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
             peer->effective_weight = 0;
         }
 
-        /* ngx_unlock_mutex(rrp->peers->mutex); */
-
     } else {
 
         /* mark peer live if check passed */
@@ -642,11 +640,12 @@ ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
 
     peer->conns--;
 
+    ngx_http_upstream_rr_peer_unlock(rrp->peers, peer);
+    ngx_http_upstream_rr_peers_unlock(rrp->peers);
+
     if (pc->tries) {
         pc->tries--;
     }
-
-    /* ngx_unlock_mutex(rrp->peers->mutex); */
 }
 
 
@@ -664,9 +663,6 @@ ngx_http_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc,
 
     peer = rrp->current;
 
-    /* TODO: threads only mutex */
-    /* ngx_lock_mutex(rrp->peers->mutex); */
-
     ssl_session = peer->ssl_session;
 
     rc = ngx_ssl_set_session(pc->connection, ssl_session);
@@ -674,8 +670,6 @@ ngx_http_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc,
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                    "set session: %p", ssl_session);
 
-    /* ngx_unlock_mutex(rrp->peers->mutex); */
-
     return rc;
 }
 
@@ -700,14 +694,9 @@ ngx_http_upstream_save_round_robin_peer_session(ngx_peer_connection_t *pc,
 
     peer = rrp->current;
 
-    /* TODO: threads only mutex */
-    /* ngx_lock_mutex(rrp->peers->mutex); */
-
     old_ssl_session = peer->ssl_session;
     peer->ssl_session = ssl_session;
 
-    /* ngx_unlock_mutex(rrp->peers->mutex); */
-
     if (old_ssl_session) {
 
         ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
diff --git a/src/http/ngx_http_upstream_round_robin.h b/src/http/ngx_http_upstream_round_robin.h
index 53beac8e3..0dca40e18 100644
--- a/src/http/ngx_http_upstream_round_robin.h
+++ b/src/http/ngx_http_upstream_round_robin.h
@@ -63,6 +63,13 @@ struct ngx_http_upstream_rr_peers_s {
 };
 
 
+#define ngx_http_upstream_rr_peers_rlock(peers)
+#define ngx_http_upstream_rr_peers_wlock(peers)
+#define ngx_http_upstream_rr_peers_unlock(peers)
+#define ngx_http_upstream_rr_peer_lock(peers, peer)
+#define ngx_http_upstream_rr_peer_unlock(peers, peer)
+
+
 typedef struct {
     ngx_http_upstream_rr_peers_t   *peers;
     ngx_http_upstream_rr_peer_t    *current;