Merge of r4498:

Fix of rbtree lookup on hash collisions.

Previous code incorrectly assumed that nodes with identical keys are linked
together.  This might not be true after tree rebalance.

Patch by Lanshun Zhou.

1 files changed, 14 insertions, 19 deletions

diff --git a/src/http/modules/ngx_http_limit_zone_module.c b/src/http/modules/ngx_http_limit_zone_module.c
index d92f5354a..9a8ea87fe 100644
--- a/src/http/modules/ngx_http_limit_zone_module.c
+++ b/src/http/modules/ngx_http_limit_zone_module.c
@@ -194,31 +194,26 @@ ngx_http_limit_zone_handler(ngx_http_request_t *r)
 
         /* hash == node->key */
 
-        do {
-            lz = (ngx_http_limit_zone_node_t *) &node->color;
+        lz = (ngx_http_limit_zone_node_t *) &node->color;
 
-            rc = ngx_memn2cmp(vv->data, lz->data, len, (size_t) lz->len);
+        rc = ngx_memn2cmp(vv->data, lz->data, len, (size_t) lz->len);
 
-            if (rc == 0) {
-                if ((ngx_uint_t) lz->conn < lzcf->conn) {
-                    lz->conn++;
-                    goto done;
-                }
-
-                ngx_shmtx_unlock(&shpool->mutex);
-
-                ngx_log_error(lzcf->log_level, r->connection->log, 0,
-                              "limiting connections by zone \"%V\"",
-                              &lzcf->shm_zone->shm.name);
-
-                return NGX_HTTP_SERVICE_UNAVAILABLE;
+        if (rc == 0) {
+            if ((ngx_uint_t) lz->conn < lzcf->conn) {
+                lz->conn++;
+                goto done;
             }
 
-            node = (rc < 0) ? node->left : node->right;
+            ngx_shmtx_unlock(&shpool->mutex);
 
-        } while (node != sentinel && hash == node->key);
+            ngx_log_error(lzcf->log_level, r->connection->log, 0,
+                          "limiting connections by zone \"%V\"",
+                          &lzcf->shm_zone->shm.name);
+
+            return NGX_HTTP_SERVICE_UNAVAILABLE;
+        }
 
-        break;
+        node = (rc < 0) ? node->left : node->right;
     }
 
     n = offsetof(ngx_rbtree_node_t, color)