means that zero is returned, and the kernel keeps mounting (and it
probably ends up in a deadlock/memory corruption somewhere).
2) 'nentries' and 'gnentries' are int and user-controlled, and there's no
check to ensure they are greater than zero. Since they are used to
compute the size of two copyin's, a user can control the copied size
by giving a negative value (like 128-2^29), and thus overwrite kernel
memory.
Both triggerable from root only.