Re: [PATCH v2 0/3] pidfd: add task path ioctls

* Chen Linxuan via:

This series adds PIDFD_GET_EXE, PIDFD_GET_CWD, and PIDFD_GET_ROOT. Each
ioctl takes no argument and returns a close-on-exec O_PATH file
descriptor referencing the corresponding task path.  The new ioctls use
the same ptrace permission check and nonzero-argument rejection as the
existing pidfd namespace ioctls.

How would one upgrade the O_PATH descriptor to a full descriptor without
a mounted /proc?

Thanks,
Florian