Re: t5800-*.sh: Intermittent test failures

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 3, 2011, 01:30 UTC
Message-ID: <7vobwugfgr.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CAGdFq_h+Hpv9perLTU2rbdT6oZ3kZy22t5nghJQeEjNGvunL+A@mail.gmail.com>

Sverre Rabbelier <srabbelier@gmail.com> writes:

> Ævar, this seems like something we could look at during the mini
> GitTogether in Amsterdam this Saturday, no?

Have fun.

I think I happened to hit this while testing today's 'pu' that hasn't been pushed out. The process chain looks like this:

pid  command                     stuck at
4767 sh t5800-remote-helpers.sh  wait4(-1)
 4793 git push                   read(6)
  4809 git-remote-testgit        wait4(4906)
   4906 git fast-import          wait4(4912)
    4912 git-fast-import         read(0)

lr-x------ 1 junio junio 64 Nov 2 18:21 /proc/4793/fd/6 -> pipe:[133037701] l-wx------ 1 junio junio 64 Nov 2 18:21 /proc/4793/fd/7 -> pipe:[133037700] lr-x------ 1 junio junio 64 Nov 2 18:21 /proc/4793/fd/8 -> pipe:[133037701] lr-x------ 1 junio junio 64 Nov 2 18:05 /proc/4809/fd/0 -> pipe:[133037700] l-wx------ 1 junio junio 64 Nov 2 18:05 /proc/4809/fd/1 -> pipe:[133037701] lr-x------ 1 junio junio 64 Nov 2 18:05 /proc/4906/fd/0 -> pipe:[133037700] l-wx------ 1 junio junio 64 Nov 2 18:05 /proc/4906/fd/1 -> pipe:[133037701] lr-x------ 1 junio junio 64 Nov 2 18:03 /proc/4912/fd/0 -> pipe:[133037700] l-wx------ 1 junio junio 64 Nov 2 18:03 /proc/4912/fd/1 -> pipe:[133037701]

So "git push (4793)" is stuck reading from pipe:[133037701], expecting the innermost "git-fast-import (4912)" to write to it via its standard output, but the latter is waiting to read from pipe:[133037700], hoping the former to write to it via its fd#7.

Does this deadlock ring a bell to anybody who's involved in these codepaths?