We only use the last pid from the list in NSpid entry (from
/proc/<pid>/fdinfo/<pidfd>) while restoring pidfds.
The last pid refers to the pid of the process in the most deeply nested
pid namespace. Since CRIU does not currently support nested pid
namespaces, this entry is the one we want.
After Linux 6.9, inode numbers can be used to compare pidfds. pidfds
referring to the same process will have the same inode numbers. We use
inode numbers to restore pidfds that point to dead processes.
Signed-off-by: Bhavik Sachdev <b.sachdev1904@gmail.com>
