fix curl resumable epoll related crash

runtime/curl.cpp

@@ -1129,6 +1129,15 @@ void CurlRequest::detach_multi_and_easy_handles() const noexcept {
 }
 
 static int curl_epoll_cb(int fd, void *data, event_t *ev) {
+  // Sometimes epoll callbacks can be invoked AFTER the related 'fd' is removed from epoll.
+  // It happens because our net_reactor at first stores epoll events from epoll_wait, and only then runs related callbacks (see epoll_fetch_events())
+  // Usually this situation is handled via some additional connection flags (conn_expect_query, C_WANTRD etc.)
+  // in callbacks like `server_read_write_gateway` and related.
+  // But here we try to keep it simple and not to do all of this stuff.
+  // So we need to check explicitly that this fd is still present in epoll reactor:
+  if (!(ev->state & EVT_IN_EPOLL)) {
+    return 0;
+  }
   auto *curl_request = static_cast<CurlRequest *>(data);
   php_assert(curl_request);
 

server/php-worker.cpp

@@ -234,7 +234,11 @@ void PhpWorker::state_run() noexcept {
         tvkprintf(php_runner, 3, "PHP-worker before swap context [req_id = %016llx]\n", req_id);
         php_script->iterate();
         tvkprintf(php_runner, 3, "PHP-worker after swap context [req_id = %016llx]\n", req_id);;
-        wait(0); // check for net events
+        if (php_script->state != run_state_t::finished) {
+          // We don't need to check net events when the script is going to finish.
+          // Otherwise we can fetch some net events related to this script that will be processed after the script termination.
+          wait(0);
+        }
         break;
       }
       case run_state_t::query: {