question on "cannot map memory"

[photoszzt]

I saw dmesg prints out something like this: "Cannot map memory with base addr 0x7f66a4000000 and size of 0x8000 pages". Then there's a following prints:
nvidia-peermem nv_get_p2p_free_callback:127 ERROR detected invalid context, skipping further processing

Are these two errors related? Looking at the source code, the first error is print from os_lookup_user_io_memory. In what cases the first error will shown?