Fix BZ #342683. Based on patch by Ivo Raisr.
What this does is to make sure that the initial client data segment
is marked as unaddressable. This is consistent with the behaviour of
brk when the data segment is shrunk. The "freed" memory is marked
as unaddressable.
Special tweaks were needed for s390 which was returning early from
the funtion to avoid sloppy register definedness initialisation.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15144 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/NEWS b/NEWS
index 2a61168..71e0755 100644
--- a/NEWS
+++ b/NEWS
@@ -108,6 +108,7 @@
 342353  Allow dumping full massif output while valgrind is still running
 342603  Add I2C_SMBUS ioctl support
 342635  OS X 10.10 (Yosemite) - missing system calls and fcntl code
+342683  Mark memory past the initial brk limit as unaddressable
 342795  Internal glibc __GI_mempcpy call should be intercepted
 343012  Unhandled syscall 319 (memfd_create)
 343069  Patch updating v4l2 API support