Comment # 11 on bug 1045340 from Vlastimil Babka

(In reply to Vlastimil Babka from comment #10)
> #3  0xf7afd1e2 in JavaThread::create_stack_guard_pages() () from
> /opt/novell/groupwise/client/java/lib/i386/client/libjvm.so

Looks to me like this is intended to create guard pages from userspace for
non-initial threads, which AFAIK have fixed-size stacks in pthread
implementation, so probably also in java. Pthreads seem to also have guard
pages controlled by pthread_attr_setguardsize(). Neither should care or have
issues with the kernel's guard gap implementation or gap size, as long as the
extra thread stacks are not VM_GROWSDOWN.

Seems there is a bug when java VM is invoked via JNI_CreateJavaVM () from
another binary (and not the java launcher), where these guard pages for extra
threads are applied to the initial thread and its VM_GROWSDOWN stack, where it
does have issues with the larger in-kernel gap as I analyzed above.