diff --git a/src/userprog/process.c b/src/userprog/process.c
index a507d5d..c960df9 100644
--- a/src/userprog/process.c
+++ b/src/userprog/process.c
@@ -43,7 +43,8 @@ struct process_start_data
     char *cmd_saveptr; /* Value pointed to by 'saveptr' argument used by
                           successive calls to strtok_r to split 'cmd' into
                           tokens while maintaining state. */
-    char *file_name; /* Name of the file of the process to be started. */
+    char file_name[FNAME_MAX_LEN]; /* Name of the file of the process to
+                                      be started. */
   };
 
 static thread_func start_process NO_RETURN;
@@ -58,7 +59,12 @@ process_execute (const char *cmd)
 {
   char *cmd_copy;
   tid_t tid;
-  struct process_start_data data;
+  
+  struct process_start_data *data = malloc (sizeof (struct process_start_data));
+  if (data == NULL)
+    {
+      return TID_ERROR;
+    }
 
   /* Make a copy of command.
      Otherwise there's a race between the caller and load(). */
@@ -72,17 +78,15 @@ process_execute (const char *cmd)
 
   /* Retrieve first argument of command, which is the file name
      of the process. */
-  char *file_name = strtok_r (cmd_copy, " ", &data.cmd_saveptr);
-  if (strlen (file_name) > FNAME_MAX_LEN)
-    file_name[FNAME_MAX_LEN + 1] = '\n';
+  char *file_name = strtok_r (cmd_copy, " ", &data->cmd_saveptr);
 
   /* Create a new thread to execute the command, by initializing
      it running the function 'start_process' with the appropriate
      arguments. For details of arguments, see 'start_process'. */
-  data.cmd = cmd_copy;
-  data.file_name = file_name;
-  
-  tid = thread_create (file_name, PRI_DEFAULT, start_process, &data);
+  data->cmd = cmd_copy;
+  strlcpy (data->file_name, file_name, FNAME_MAX_LEN);
+
+  tid = thread_create (file_name, PRI_DEFAULT, start_process, data);
   if (tid == TID_ERROR)
     palloc_free_page (cmd_copy); 
   return tid;
@@ -105,7 +109,6 @@ start_process (void *proc_start_data)
   bool success;
 
   struct process_start_data *data = proc_start_data;
-  ASSERT (data->cmd_saveptr != NULL);
 
   /* Initialize interrupt frame and load executable. */
   memset (&if_, 0, sizeof if_);
@@ -118,7 +121,7 @@ start_process (void *proc_start_data)
   if (!success) 
     {
       palloc_free_page (data->cmd);
-      thread_exit ();
+      goto fail;
     }
 
   /* Initialize user process stack and free page used to store the
@@ -130,7 +133,7 @@ start_process (void *proc_start_data)
   if (!success)
     {
       process_exit ();
-      thread_exit ();
+      goto fail;
     }
 
   /* Start the user process by simulating a return from an
@@ -141,6 +144,11 @@ start_process (void *proc_start_data)
      and jump to it. */
   asm volatile ("movl %0, %%esp; jmp intr_exit" : : "g" (&if_) : "memory");
   NOT_REACHED ();
+
+/* If starting the process failed, free its common resources and exit. */
+ fail:
+  free (data);
+  thread_exit ();
 }
 
 /* Helper function that initializes the stack of a newly created