Line 830 in heapRegion.cpp should be followed by lines like this:
*failures = true;
return;
http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/file/2a8e87190908/src/share/vm/gc/g1/heapRegion.cpp#l830
*failures = true;
return;
http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/file/2a8e87190908/src/share/vm/gc/g1/heapRegion.cpp#l830