Re: [PATCH] t5562: chunked sleep to avoid lost SIGCHILD

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 19, 2019, 18:38 UTC
Message-ID: <xmqq1s4339ow.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20190218205028.32486-1-max@max630.net>

Max Kirillov <max@max630.net> writes:

Show 24 quoted lines

> If was found during stress-test run that a test may hang by 60 seconds.
> It supposedly happens because SIGCHILD was received before sleep has
> started.
>
> Fix by looping by smaller chunks, checking $exited after each of them.
> Then lost SIGCHILD would not cause longer delay than 1 second.
>
> Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
> Signed-off-by: Max Kirillov <max@max630.net>
> ---
> Submitting as proper patch. Note: I believe it does not relate to other issues
> discussed in this thread.
>  t/t5562/invoke-with-content-length.pl | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/t/t5562/invoke-with-content-length.pl b/t/t5562/invoke-with-content-length.pl
> index 0943474af2..257e280e3b 100644
> --- a/t/t5562/invoke-with-content-length.pl
> +++ b/t/t5562/invoke-with-content-length.pl
> @@ -29,7 +29,12 @@
>  }
>  print $out $body_data or die "Cannot write data: $!";
>  
> -sleep 60; # is interrupted by SIGCHLD

Ah, of course. If SIGCHLD interrupts, sets $existed in the handler, then we won't go back to sleep. But if the signal came before the sleep starts, we spend full 60 seconds here before we check $exited.

Makes sense.

Show 9 quoted lines

> +my $counter = 0;
> +while (not $exited and $counter < 60) {
> +        sleep 1;
> +        $counter = $counter + 1;
> +}
> +
>  if (!$exited) {
>          close($out);
>          die "Command did not exit after reading whole body";