Unmap crash with map_read


I experience a crash in clEnqueueUnmapBufferObject if I map a buffer (created with USE_HOST_PTR) with a READ access .

If use READ_WRITE map access or if I use COPY_HSOT_PTR : there is no problem.

Is it a bug (I use nVidia 195.55 under vista 64), or a bad usage of mapping?