Occasionally, the test fails. We need to backport this upstream change:
Author: James Lemke <firstname.lastname@example.org>
Date: Tue May 19 12:10:26 2015 -0700
Fix for test "malloc_usable_size: expected 7 but got 11"
[BZ #17581] The checking chain of unused chunks was terminated by a hash of
the block pointer, which was sometimes confused with the chunk length byte.
We now avoid using a length byte equal to the magic byte.
(NB: A first fix was reverted.)
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.