Troubleshooting a Linux process follows the same general methodology as that used with traditional UNIX systems. In both systems, for process hangs, we identify the system resources being used by the process and attempt to identify the cause for the process to stop responding. With application core dumps, we must identify the signal for which the process terminated and proceed with acquiring a stack trace to identify system calls made by the process at the time it died. There exists neither a "golden" troubleshooting path nor a set of instructions that can be applied for all cases. Some conditions are much easier to solve than others, but with a good understanding of the fundamentals, a solution is not far from reach.
This chapter explains various facets of Linux processes. We begin by examining the structure of a process and its life cycle from creation to termination. This is followed by a discussion of Linux threads. The aforementioned establish a basis for proceeding with a discussion of process hangs and core dumps.