In file src/event/ngx_event_timer.c: function: void ngx_event_expire_timers (void) { .... ... for ( ;; ) { ngx_mutex_lock(ngx_event_timer_mutex); root = ngx_event_timer_rbtree.root; if (root == sentinel) { return; } ... ... } While timer rb-tree is empty, mutex_lock 'ngx_event_timer_mutex' would not unlock! This bug is avalby ljzwaterbull - Nginx Mailing List - English