Processo de zumbis na Wikipedia:
On Unix and Unix-like computer operating systems, a zombie process or defunct process is a process that has completed execution but still has an entry in the process table. This entry is still needed to allow the parent process to read its child's exit status. The term zombie process derives from the common definition of zombie — an undead person. In the term's metaphor, the child process has "died" but has not yet been "reaped". Also, unlike normal processes, the kill command has no effect on a zombie process.
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Zombies can be identified in the output from the Unix ps command by the presence of a "Z" in the "STAT" column. Zombies that exist for more than a short period of time typically indicate a bug in the parent program, or just an uncommon decision to reap children. If the parent program is no longer running, zombie processes typically indicate a bug in the operating system. As with other leaks, the presence of a few zombies is not worrisome in itself, but may indicate a problem that would grow serious under heavier loads. Since there is no memory allocated to zombie processes except for the process table entry itself, the primary concern with many zombies is not running out of memory, but rather running out of process ID numbers.
Não wory, isso acontece às vezes. Não há necessidade de registrar este tipo de evento.