Troubleshooting Defunct (Zombie) Processes on Linux

“At work (LNI) we have a tool which implements a remotely
controlled RDMA agent using the OpenFabrics interface. The agent is
used for compliance, interoperability, and performance testing. For
quite some time we’ve had a problem where sometimes the agent hangs
and then after sending SIGINT (ctrl-C or kill) the agent shows up
as ‘defunct’ with a Zombie state in the output of ps.

“Normally a zombie process means that the process has died but
remains in the process table because the parent hasn’t called
wait() to ‘reap’ the process and retrieve the return code…”

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