diff -r 67fbf09d3fa5 src/lib/ioloop-kqueue.c
--- a/src/lib/ioloop-kqueue.c	Wed Nov 10 16:09:14 2010 +0000
+++ b/src/lib/ioloop-kqueue.c	Sun Nov 14 18:09:46 2010 +0000
@@ -6,7 +6,7 @@
 
 #include "lib.h"
 
-#ifdef IOLOOP_KQUEUE
+#ifndef IOLOOP_KQUEUE
 
 #include "array.h"
 #include "fd-close-on-exec.h"
@@ -125,8 +125,22 @@
 	/* wait for events */
 	events = array_get_modifiable(&ctx->events, &events_count);
 	ret = kevent (ctx->kq, NULL, 0, events, events_count, &ts);
-	if (ret < 0 && errno != EINTR)
-		i_fatal("kevent(): %m");
+	if (ret < 0 && errno != EINTR) {
+		memset(&ts, 0, sizeof(ts));
+		if (kevent (ctx->kq, NULL, 0, events, events_count, &ts) == 0)
+			i_fatal("kevent: invalid timespec");
+		for (i = 0; i < (int)events_count; i++) {
+			struct kevent *e = &events[i];
+			io = (void *)e->udata;
+
+			if (kevent(ctx->kq, NULL, 0, e, 1, &ts) < 0) {
+				i_panic("kevent: invalid event: ident=%p filter=%d flags=%u fflags=%u fd=%d callback=%p",
+					(void *)e->ident, e->filter, e->flags, e->fflags,
+					io->fd, io->io.callback);
+			}
+		}
+		i_panic("kevent(): dunno why it broke");
+	}
 
 	/* reference all IOs */
 	for (i = 0; i < ret; i++) {