diff --git a/src/mworker.c b/src/mworker.c
index a77c0a1..48a2c5b 100644
--- a/src/mworker.c
+++ b/src/mworker.c
@@ -406,6 +406,9 @@
 	if (tid != 0)
 		return 1;
 
+	if (proc_self->ipc_fd[1] < 0) /* proc_self was incomplete and we can't find the socketpair */
+		return 1;
+
 	fcntl(proc_self->ipc_fd[1], F_SETFL, O_NONBLOCK);
 	/* In multi-tread, we need only one thread to process
 	 * events on the pipe with master