commit c6a4f805d0a8376260cf67bfeea12a21517c0f6d
Author: Lars Müller <lars@samba.org>
Date:   Tue Aug 12 23:01:20 2014 +0200

    build: disable mmap on s390 systems
    
    If build on an s390(x) system define HAVE_INCOHERENT_MMAP to disable
    mmap by default on this architecture.  This case isn't caught with the
    check in front of these lines.
    
    Bug: https://bugzilla.samba.org/show_bug.cgi?id=10765
    
    Signed-off-by: Lars Müller <lars@samba.org>

diff --git a/docs-xml/smbdotconf/tuning/usemmap.xml b/docs-xml/smbdotconf/tuning/usemmap.xml
index c23fc35..e450ddf 100644
--- a/docs-xml/smbdotconf/tuning/usemmap.xml
+++ b/docs-xml/smbdotconf/tuning/usemmap.xml
@@ -5,10 +5,11 @@
                  xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
 <description>
     <para>This global parameter determines if the tdb internals of Samba can
-    depend on mmap working correctly on the running system. Samba requires a coherent
-    mmap/read-write system memory cache. Currently only HPUX does not have such a
-    coherent cache, and so this parameter is set to <constant>no</constant> by
-    default on HPUX. On all other systems this parameter should be left alone. This
+    depend on mmap working correctly on the running system. Samba requires a
+    coherent mmap/read-write system memory cache. Currently HPUX and s390(x)
+    do not have such a coherent cache, and so this parameter is set to
+    <constant>no</constant> by default on these systems. On all other systems
+    this parameter should be left alone. This
     parameter is provided to help the Samba developers track down problems with
     the tdb internal code.
     </para>
diff --git a/lib/replace/wscript b/lib/replace/wscript
index a7384e8..5746abb 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('HAVE_INCOHERENT_MMAP', 1)
+
     conf.SAMBA_BUILD_ENV()
 
     conf.CHECK_CODE('''