MFC r296652:
Do not perform unneccessary shared recursion on the allproc_lock in
pfs_visible().

MFC r258088:
Add check for buflen overflow by comparing the buflen with both offset
and resid.

MFC r258397:
Redo r258088 to avoid relying on signed arithmetic overflow.

MFC r258088:
Add check for buflen overflow by comparing the buflen with both offset
and resid.

MFC r258397:
Redo r258088 to avoid relying on signed arithmetic overflow.