jmap failed to attach to core file with message "Error attaching to core file: Can't attach to the core file" with latest 7u60 builds.
Issue could be reproduced with linux-i586 bundles.

$JAVA_HOME/bin/java Test &
kill -11 $!
$JAVA_HOME/bin/jmap $JAVA_HOME/bin/java ./core
Attaching to core core from executable /blablabla/linux-i586/bin/java, please wait...
Error attaching to core file: Can't attach to the core file