Physical pages can be mapped more than once, it is the mapping that describes protection bits. Implementing an in-place FUSE filesystem for example would have n

Physical pages can be mapped more than once, it is the mapping that describes protection bits. Implementing an in-place FUSE filesystem for example would have no bearing on whether other mappings of the same file lacked execute bits, and in the case of the FUSE interface, the kernel does not even know the original source of the data I think this could also be achieved with a loopback device setup to cover some of the file, again no relevance to NX etc, but that would require setuid or similar to configure the device