There is a problem in ascii_glyph_lookup(). It doesn't check the return value of grub_malloc(). If memory can't be allocated, then NULL pointer will be written to. This patch fixes the problem by fallbacking to unknown_glyph when grub_malloc() returns NULL. Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>