Provided by: systemtap-doc_2.3-1ubuntu1.4_all 

NAME
function::pstrace - Chain of processes and pids back to init(1)
SYNOPSIS
pstrace:string(task:long)
ARGUMENTS
task
Pointer to task struct of process
DESCRIPTION
This function returns a string listing execname and pid for each process starting from task back to the
process ancestor that init(1) spawned.
SystemTap Tapset Reference March 2016 FUNCTION::PSTRACE(3stap)