--- coregrind/m_aspacemgr/aspacemgr-common.c.orig
+++ coregrind/m_aspacemgr/aspacemgr-common.c
@@ -458,7 +458,11 @@ VgStack* VG_(am_alloc_VgStack)( /*OUT*/Addr* initial_sp )
    szB = VG_STACK_GUARD_SZB
          + VG_STACK_ACTIVE_SZB + VG_STACK_GUARD_SZB;

+#if defined(__OpenBSD__)
+   sres = VG_(am_mmap_anon_float_valgrind_stack)( szB );
+#else
    sres = VG_(am_mmap_anon_float_valgrind)( szB );
+#endif
    if (sr_isError(sres))
       return NULL;

