I watch this case ,
one ruby.bin process use 100% cpu.

kill the process output error info to log file.

redmine version is redmine-2.1.2-1

log content

Completed 500 Internal Server Error in 1233537ms

SignalException (SIGTERM):
lib/plugins/rfpdf/lib/fpdf/chinese.rb:299:in MBWrite'
lib/plugins/rfpdf/lib/fpdf/chinese.rb:258:inWrite'
lib/plugins/rfpdf/lib/tcpdf.rb:4298:in addHtmlLink'
lib/plugins/rfpdf/lib/tcpdf.rb:3533:inwriteHTML'
lib/plugins/rfpdf/lib/tcpdf.rb:3506:in each'
lib/plugins/rfpdf/lib/tcpdf.rb:3506:inwriteHTML'
lib/plugins/rfpdf/lib/tcpdf.rb:3617:in writeHTMLCell'
lib/redmine/export/pdf.rb:122:inRDMwriteHTMLCell'
lib/redmine/export/pdf.rb:739:in write_wiki_page'
lib/redmine/export/pdf.rb:719:inwiki_page_to_pdf'
app/controllers/wiki_controller.rb:76:in `show'