endless loop in probable_prime

[Salz, Rich]

>    BN_bin2bn assumes that the size of a BN_ULONG (the type of a bn->d) is
    BN_BYTES. You have already told us that sizeof(*d) is 4. So BN_BYTES
    should also be 4. If BN_BYTES is being incorrectly set to 8 on your
    platform then that would explain the discrepancy. Can you check?

This seems HIGHLY likely since Ronny said earlier that the same config/toolchain is used for 32bit userspace and 64bit kernel, right?