When building with ubsan enabled (--enable-uban) on Linux x86_64 and doing jtreg tests afterwards I run into this error :

/jdk/src/java.base/unix/native/libjava/ProcessImpl_md.c:562:5: runtime error: null pointer passed as argument 2, which is declared to never be null
    #0 0x7fd95bec78d8 in spawnChild /jdk/src/java.base/unix/native/libjava/ProcessImpl_md.c:562
    #1 0x7fd95bec78d8 in startChild /jdk/src/java.base/unix/native/libjava/ProcessImpl_md.c:612
    #2 0x7fd95bec78d8 in Java_java_lang_ProcessImpl_forkAndExec /jdk/src/java.base/unix/native/libjava/ProcessImpl_md.c:712
    #3 0x7fd93797a06d (<unknown module>)

this is the memcpy call getting an unexpected null pointer :
    memcpy(buf+offset, c->pdir, sp.dirlen); gets a second parameter null.
Something similar was discussed and fixed here https://bugs.python.org/issue27570 for Python .