Created attachment 1142511 [details]
tst-stdio-exit-lock.c

The test case for this upstream bug:

  http://sourceware.org/bugzilla/show_bug.cgi?id=12847

exercises a different code path as well, and crashes occasionally even if swbz#12847 is fixed.

This was corrected in this upstream commit, which is currently missing in Red Hat Enterprise Linux 6:

commit f22e10748fbabbf07161eb7a5540b8c0e18553c4
Author: Ulrich Drepper <drepper>
Date:   Fri Sep 9 16:15:25 2011 -0400

    Don't lock string streams in stream cleanup code

The attached test case triggers this bug about 80% of the time on my test VM.  It has to be run in a shell script, like this:

set -e
for x in `seq 1 100` ; do
  ./tst-stdio-exit-lock
done