Re: [Dovecot] unkillable imap process(es) with high CPU-usage

If you can't kill a process with -9, the bug is in the kernel and there's nothing Dovecot can do about it. User spaces processes can't create unkillable processes unless something's broken. It just means the process is doing an uninterruptable sleep (in BSD notation, a tsleep() without PCATCH set). This may be an I/O operation, resource shortage etc. and needn't be a kernel bug.