diff --git a/lib/replace/wscript b/lib/replace/wscript
index a7384e8..fae88e5 100644
--- a/lib/replace/wscript
+++ b/lib/replace/wscript
@@ -561,6 +561,10 @@ removeea setea
                     define='HAVE_INCOHERENT_MMAP',
                     msg="Checking for HAVE_INCOHERENT_MMAP")
 
+    # mmap on s390(x) leads to TDB corruption; see also bug 10765
+    if conf.env['SYSTEM_UNAME_MACHINE'] == 's390' or conf.env['SYSTEM_UNAME_MACHINE'] == 's390x':
+        conf.DEFINE('MMAP_BLACKLIST', 1)
+
     conf.SAMBA_BUILD_ENV()
 
     conf.CHECK_CODE('''