diff --git a/src/exec.c b/src/exec.c
index 6fea52e..e0a04f3 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -9,6 +9,7 @@
 #include <sched.h>
 #include <errno.h>
 #include <string.h>
+#include <signal.h>
 #include <fcntl.h>
 #include <inttypes.h>
 #include "syscall.h"
@@ -407,7 +408,8 @@ int hyper_exec_cmd(char *json, int length)
 	}
 
 	arg.exec = exec;
-	pid = clone(hyper_do_exec_cmd, stack + stacksize, CLONE_VM| CLONE_FILES, &arg);
+	pid = clone(hyper_do_exec_cmd, stack + stacksize, CLONE_VM| CLONE_FILES| SIGCHLD, &arg);
+	fprintf(stdout, "do_exec_cmd pid %d\n", pid);
 	free(stack);
 	if (pid < 0) {
 		perror("clone hyper_do_exec_cmd failed");
diff --git a/src/init.c b/src/init.c
index dfd6a96..7893c08 100644
--- a/src/init.c
+++ b/src/init.c
@@ -468,7 +468,7 @@ int hyper_start_containers(struct hyper_pod *pod)
 		goto out;
 	}
 
-	pid = clone(hyper_do_start_containers, stack + stacksize, CLONE_VM| CLONE_FILES, &arg);
+	pid = clone(hyper_do_start_containers, stack + stacksize, CLONE_VM| CLONE_FILES| SIGCHLD, &arg);
 	free(stack);
 	if (pid < 0) {
 		perror("enter container pid ns failed");
@@ -932,7 +932,7 @@ static int hyper_cmd_read_file(char *json, int length, uint32_t *datalen, uint8_
 	arg.data = data;
 	sprintf(arg.root, "/tmp/hyper/%s/root/%s/", c->id, c->rootfs);
 
-	pid = clone(hyper_do_cmd_read_file, stack + stacksize, CLONE_VM, &arg);
+	pid = clone(hyper_do_cmd_read_file, stack + stacksize, CLONE_VM| SIGCHLD, &arg);
 	free(stack);
 	if (pid < 0) {
 		perror("fail to fork writter process");