2 files changed, 3 insertions, 6 deletions

diff --git a/arch/um/drivers/xterm.c b/arch/um/drivers/xterm.c
index 386f8b952982..850221d9b4c9 100644
--- a/arch/um/drivers/xterm.c
+++ b/arch/um/drivers/xterm.c
@@ -136,8 +136,6 @@ int xterm_open(int input, int output, int primary, void *d,
                 return(pid);
         }
 
-        if(data->stack == 0) free_stack(stack, 0);
-
         if (data->direct_rcv) {
                 new = os_rcv_fd(fd, &data->helper_pid);
         } else {
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index 8a78bf03b468..d13299cfa318 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -50,7 +50,8 @@ static int helper_child(void *arg)
 }
 
 /* Returns either the pid of the child process we run or -E* on failure.
- * XXX The alloc_stack here breaks if this is called in the tracing thread */
+ * XXX The alloc_stack here breaks if this is called in the tracing thread, so
+ * we need to receive a preallocated stack (a local buffer is ok). */
 int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
                unsigned long *stack_out)
 {
@@ -113,10 +114,8 @@ out_close:
                 close(fds[1]);
         close(fds[0]);
 out_free:
-        if (stack_out == NULL)
+        if ((stack_out == NULL) || (*stack_out == 0))
                 free_stack(stack, 0);
-        else
-                *stack_out = stack;
         return ret;
 }