flat: fix unmap len in load error path

The data chunk is mmaped with 'len' which remains unchanged, so use that
when unmapping in the error path rather than trying to recalculate (and
incorrectly so) the value used originally.

Signed-off-by: Mike Frysinger <[email protected]>
Acked-by: David McCullough <[email protected]>
Acked-by: Greg Ungerer <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Hirokazu Takata <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Acked-by: David Howells <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

fs/binfmt_flat.c

@@ -596,7 +596,7 @@ static int load_flat_file(struct linux_binprm * bprm,
 		if (IS_ERR_VALUE(result)) {
 			printk("Unable to read data+bss, errno %d\n", (int)-result);
 			do_munmap(current->mm, textpos, text_len);
-			do_munmap(current->mm, realdatastart, data_len + extra);
+			do_munmap(current->mm, realdatastart, len);
 			ret = result;
 			goto err;
 		}