A lot of SIGSEGV while strace'ing java process

Question

Interesting stuff occurred while I debug one of the unit tests on CI server (maven build actually). I connect to java process with strace -ff -e trace=network -p [pid]

Answer 1

Since this is java, it means that your JVM is using SIGSEGVs for something. Common uses include

• null pointer dereferences -- the JVM catches SIGSEGVs to address 0 and turns them into NullPointerExceptions

• garbage collection write barriers -- rarely changed pages are marked read only and SEGVs catch writes to them. This way the garbage collector doesn't have to rescan all of memory all of the time.