add check

CCXXXI · Jan 10, 2021 · 03d0f98 · 03d0f98
1 parent 3a03ccb
commit 03d0f98
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/src/userprog/syscall.c b/src/userprog/syscall.c
@@ -265,6 +265,9 @@ static pid_t exec(const char *cmd_line)
     pid_t pid = process_execute(cmd_line);
     lock_release(&file_lock);
 
+    if (pid == TID_ERROR)
+        return -1;
+
     struct process *child = get_child(pid);
     sema_down(&child->sema_load);