6662086: 6u4+, 7b11+: CMS never clears referents when -XX:+ParallelRefProcEnabled Summary: Construct the relevant CMSIsAliveClosure used by CMS during parallel reference processing with the correct span. It had incorrectly been constructed with an empty span, a regression introduced in 6417901. Reviewed-by: jcoomes

cfeea66a3fa8ca3686a7cfa2d0ce8ab0169f168d jdk7-b24
cbc8ad9dd0e085a607427ea35411990982f19a36 jdk7-b25