Maybe I've missed it in the flurry of patches, but I still see no sign of timeouts being enforced across plugins.
http://grokbase.com/p/perl/qpsmtpd/097nr0gyr2/never-times-out http://www.nntp.perl.org/group/perl.qpsmtpd/2008/02/msg7779.html Hanno once developed some code to address the issue, but I don't know what became of that. http://grokbase.com/t/perl/qpsmtpd/0864wdzm0n/per-plugin-hook-timeouts