On February 14, 2019 17:34, Max Kirillov wrote: > To: Randall S. Becker <rsbec...@nexbridge.com> > Cc: 'Johannes Schindelin via GitGitGadget' <gitgitgad...@gmail.com>; > git@vger.kernel.org; 'Junio C Hamano' <gits...@pobox.com>; 'Max Kirillov' > <m...@max630.net> > Subject: Re: [PATCH 0/1] Fix hang in t5562, introduced in v2.21.0-rc1 > > On Thu, Feb 14, 2019 at 05:17:26PM -0500, Randall S. Becker wrote: > > Unfortunately, subtest 13 still hangs on NonStop, even with this > > patch, so our Pipeline still hangs. I'm glad it's better on Azure, but > > I don't think this actually addresses the root cause of the hang. This > > is now the fourth attempt at fixing this. Is it possible this is not > > the test that is failing, but actually the git-http-backend? The code > > is not in a loop, if that helps. It is not consuming any significant > > cycles. I don't know that part of the code at all, sadly. The code is > > here: > > > > * in the operating system from here up * > > cleanup_children + 0x5D0 (UCr) > > ... so does the process which the stack was taken from has any children > processes still? > > I could imagine if a child somehow manages to end up in uninterruptible > sleep, then probably it would never complete this way, wouldn't it?
Yes, this is typical of a hang. Two processes reading on the same pipe, or one reading on a pipe and the other waiting for something that never shows. Or one process attempting both reading and writing on the same pipe (no kernel threads here). I did not see anything actually in sleep. perl is in a close call, waiting for its output to be consumed - which never happens, making me suspect this is a pipe setup issue, but I can't demonstrate that, sorry.
