Test suite failure in chroot on oneiric host

[Evan Broder]

I'm consistently running into build failures from the test suite
trying to test a patch for bug #586942. I've posted the full build log
to http://web.mit.edu/broder/Public/upstart_1.3-0ubuntu11+broder1-amd64-20111105-1759
in case anybody finds it interesting, but I don't think there's
anything important outside of this snippet:

 test_job_process: tests/test_job_process.c:3726: test_handler:
Assertion `(waitid (P_PID, pid, &info, 2 | 0x01000000)) == 0' failed.
 /bin/bash: line 5: 27647 Aborted                 (core dumped) ${dir}$tst
 FAIL: test_job_process

I see this error consistently, both with my patch and without, any
time I try to build using sbuild on my oneiric laptop. However, the
error doesn't occur when I build directly (without a chroot tool).

I also tried just replicating the section of the code which triggered
the assertion error (fork(); raise(SIGTSTP) in the child; waitid() in
the parent), but that never seems to trigger the error, even within
the chroot.

I'm going to try to upload to a PPA builder to try and avoid the
issue, but I'm at a bit of a loss for how to continue to debug the
issue locally, and would appreciated help.

Thanks,
 - Evan