Tweaked callbacks to prevent race condition (https://github.com/libevent/libevent...

diff --git a/event.c b/event.c
index b97f1dbfd276724a76ea9c6d6415f08d1dd41be0..0c1f4f92320674960f1873077a5f05a3425f8507 100644 (file)
--- a/event.c
+++ b/event.c
@@ -1454,6 +1454,10 @@ done:
 static inline void
 event_persist_closure(struct event_base *base, struct event *ev)
 {
+
+       // Define our callback, we use this to store our callback before it's executed
+       void (*evcb_callback)(evutil_socket_t, short, void *);
+
        /* reschedule the persistent event if we have a timeout. */
        if (ev->ev_io_timeout.tv_sec || ev->ev_io_timeout.tv_usec) {
                /* If there was a timeout, we want it to run at an interval of
@@ -1496,8 +1500,8 @@ event_persist_closure(struct event_base *base, struct event *ev)
                event_add_nolock_(ev, &run_at, 1);
        }
 
-       // Get our callback before we release the lock
-       void (*evcb_callback)(evutil_socket_t, short, void *) = *ev->ev_callback;
+       // Save our callback before we release the lock
+       evcb_callback = *ev->ev_callback;
 
        // Release the lock
        EVBASE_RELEASE_LOCK(base, th_base_lock);
@@ -1564,34 +1568,40 @@ event_process_active_single_queue(struct event_base *base,
                        EVUTIL_ASSERT(ev != NULL);
                        event_persist_closure(base, ev);
                        break;
-               case EV_CLOSURE_EVENT:
+               case EV_CLOSURE_EVENT: {
+                       void (*evcb_callback)(evutil_socket_t, short, void *) = *ev->ev_callback;
                        EVUTIL_ASSERT(ev != NULL);
                        EVBASE_RELEASE_LOCK(base, th_base_lock);
-                       (*ev->ev_callback)(
-                               ev->ev_fd, ev->ev_res, ev->ev_arg);
-                       break;
-               case EV_CLOSURE_CB_SELF:
+                       evcb_callback(ev->ev_fd, ev->ev_res, ev->ev_arg);
+               }
+               break;
+               case EV_CLOSURE_CB_SELF: {
+                       void (*evcb_selfcb)(struct event_callback *, void *) = evcb->evcb_cb_union.evcb_selfcb;
                        EVBASE_RELEASE_LOCK(base, th_base_lock);
-                       evcb->evcb_cb_union.evcb_selfcb(evcb, evcb->evcb_arg);
-                       break;
+                       evcb_selfcb(evcb, evcb->evcb_arg);
+               }
+               break;
                case EV_CLOSURE_EVENT_FINALIZE:
-               case EV_CLOSURE_EVENT_FINALIZE_FREE:
+               case EV_CLOSURE_EVENT_FINALIZE_FREE: {
+                       void (*evcb_evfinalize)(struct event *, void *) = ev->ev_evcallback.evcb_cb_union.evcb_evfinalize;
                        base->current_event = NULL;
                        EVUTIL_ASSERT(ev != NULL);
                        EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING));
                        EVBASE_RELEASE_LOCK(base, th_base_lock);
-                       ev->ev_evcallback.evcb_cb_union.evcb_evfinalize(ev, ev->ev_arg);
+                       evcb_evfinalize(ev, ev->ev_arg);
                        event_debug_note_teardown_(ev);
                        if (evcb->evcb_closure == EV_CLOSURE_EVENT_FINALIZE_FREE)
                                mm_free(ev);
-                       break;
-               case EV_CLOSURE_CB_FINALIZE:
+               }
+               break;
+               case EV_CLOSURE_CB_FINALIZE: {
+                       void (*evcb_cbfinalize)(struct event_callback *, void *) = evcb->evcb_cb_union.evcb_cbfinalize;
                        base->current_event = NULL;
                        EVUTIL_ASSERT((evcb->evcb_flags & EVLIST_FINALIZING));
                        EVBASE_RELEASE_LOCK(base, th_base_lock);
-                       base->current_event = NULL;
-                       evcb->evcb_cb_union.evcb_cbfinalize(evcb, evcb->evcb_arg);
-                       break;
+                       evcb_cbfinalize(evcb, evcb->evcb_arg);
+               }
+               break;
                default:
                        EVUTIL_ASSERT(0);
                }