--- old/src/os_cpu/linux_s390/vm/os_linux_s390.cpp	2016-12-06 10:23:45.586791000 +0100
+++ new/src/os_cpu/linux_s390/vm/os_linux_s390.cpp	2016-12-06 10:23:45.444789000 +0100
@@ -473,11 +473,11 @@
 ////////////////////////////////////////////////////////////////////////////////
 // thread stack
 
-// These sizes exclude libc stack guard pages, but include
-// the HotSpot guard pages.
-size_t os::Posix::_compiler_thread_min_stack_allowed = 128 * K;
-size_t os::Posix::_java_thread_min_stack_allowed = 236 * K;
-size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * K;
+// Minimum usable stack sizes required to get to user code. Space for
+// HotSpot guard pages is added later.
+size_t os::Posix::_compiler_thread_min_stack_allowed = (52 DEBUG_ONLY(+ 32)) * K;
+size_t os::Posix::_java_thread_min_stack_allowed = (32 DEBUG_ONLY(+ 8)) * K;
+size_t os::Posix::_vm_internal_thread_min_stack_allowed = 32 * K;
 
 // Return default stack size for thr_type.
 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {