--- a/src/event/modules/ngx_select_module.c
+++ b/src/event/modules/ngx_select_module.c
@@ -18,6 +18,7 @@ static ngx_int_t ngx_select_del_event(ng
     ngx_uint_t flags);
 static ngx_int_t ngx_select_process_events(ngx_cycle_t *cycle, ngx_msec_t timer,
     ngx_uint_t flags);
+static void ngx_select_repair_fd_sets(ngx_cycle_t *cycle);
 static char *ngx_select_init_conf(ngx_cycle_t *cycle, void *conf);
 
 
@@ -343,6 +344,11 @@ ngx_select_process_events(ngx_cycle_t *c
 
     if (err) {
         ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "select() failed");
+
+        if (err == WSAENOTSOCK) {
+            ngx_select_repair_fd_sets(cycle);
+        }
+
         return NGX_ERROR;
     }
 
@@ -365,6 +371,11 @@ ngx_select_process_events(ngx_cycle_t *c
         }
 
         ngx_log_error(level, cycle->log, err, "select() failed");
+
+        if (err == EBADF) {
+            ngx_select_repair_fd_sets(cycle);
+        }
+
         return NGX_ERROR;
     }
 
@@ -425,6 +436,91 @@ ngx_select_process_events(ngx_cycle_t *c
 }
 
 
+static void
+ngx_select_repair_fd_sets(ngx_cycle_t *cycle)
+{
+    int           n;
+    socklen_t     len;
+    ngx_err_t     err;
+    ngx_socket_t  s;
+
+#if (NGX_WIN32)
+    u_int         i;
+
+    for (i = 0; i < master_read_fd_set.fd_count; i++) {
+
+        s = master_read_fd_set.fd_array[i];
+        len = sizeof(int);
+
+        if (getsockopt(s, SOL_SOCKET, SO_TYPE, (char *) &n, &len) == -1) {
+            err = ngx_socket_errno;
+
+            ngx_log_error(NGX_LOG_ALERT, cycle->log, err,
+                          "invalid descriptor #%d in read fd_set", s);
+
+            FD_CLR(s, &master_read_fd_set);
+        }
+    }
+
+    for (i = 0; i < master_write_fd_set.fd_count; i++) {
+
+        s = master_write_fd_set.fd_array[i];
+        len = sizeof(int);
+
+        if (getsockopt(s, SOL_SOCKET, SO_TYPE, (char *) &n, &len) == -1) {
+            err = ngx_socket_errno;
+
+            ngx_log_error(NGX_LOG_ALERT, cycle->log, err,
+                          "invalid descriptor #%d in write fd_set", s);
+
+            FD_CLR(s, &master_write_fd_set);
+        }
+    }
+
+#else
+
+    for (s = 0; s <= max_fd; s++) {
+
+        if (FD_ISSET(s, &master_read_fd_set) == 0) {
+            continue;
+        }
+
+        len = sizeof(int);
+
+        if (getsockopt(s, SOL_SOCKET, SO_TYPE, &n, &len) == -1) {
+            err = ngx_socket_errno;
+
+            ngx_log_error(NGX_LOG_ALERT, cycle->log, err,
+                          "invalid descriptor #%d in read fd_set", s);
+
+            FD_CLR(s, &master_read_fd_set);
+        }
+    }
+
+    for (s = 0; s <= max_fd; s++) {
+
+        if (FD_ISSET(s, &master_write_fd_set) == 0) {
+            continue;
+        }
+
+        len = sizeof(int);
+
+        if (getsockopt(s, SOL_SOCKET, SO_TYPE, &n, &len) == -1) {
+            err = ngx_socket_errno;
+
+            ngx_log_error(NGX_LOG_ALERT, cycle->log, err,
+                          "invalid descriptor #%d in write fd_set", s);
+
+            FD_CLR(s, &master_write_fd_set);
+        }
+    }
+
+    max_fd = -1;
+
+#endif
+}
+
+
 static char *
 ngx_select_init_conf(ngx_cycle_t *cycle, void *conf)
 {