Use nonblocking pipes

src/iomux_waker.c

@@ -3,6 +3,7 @@
 #include <unistd.h>
 #include <assert.h>
 #include "ucore/iomux_waker.h"
+#include "ucore/fd_utils.h"
 
 static void uc_waker_pipe_cb(struct IOMux *mux, struct IOMuxFD *fd, unsigned int event)
 {
@@ -64,6 +65,10 @@ int uc_iomux_waker_init(struct IOMux *mux, struct IOMuxWaker *wk, uc_waker_cb cb
     wk->mux = mux;
     wk->wake_cb = cb;
     wk->signaller.fd = pfds[1];
+    rc = uc_set_nonblocking(pfds[0]);
+    assert(rc == 0);
+    rc = uc_set_nonblocking(pfds[1]);
+    assert(rc == 0);
 
     if (uc_install_wake_handler(wk, pfds[0]) == 0) {
         return 0;