--- coregrind/m_syswrap/syswrap-generic.c.orig
+++ coregrind/m_syswrap/syswrap-generic.c
@@ -2240,7 +2240,13 @@
    /* Otherwise we're OK (so far).  Install aspacem's choice of
       address, and let the mmap go through.  */
    sres = VG_(am_do_mmap_NO_NOTIFY)(advised, arg2, arg3,
+#if defined(VGO_openbsd)
+	/* Could not specified VKI_MAP_STACK and VKI_MAP_FIXED at the same
+	   time */
+                                    arg4,
+#else
                                     arg4 | VKI_MAP_FIXED,
+#endif
                                     arg5, arg6);
 
    /* A refinement: it may be that the kernel refused aspacem's choice
