From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id EC83C1F453 for ; Thu, 14 Feb 2019 23:04:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728711AbfBNXEq (ORCPT ); Thu, 14 Feb 2019 18:04:46 -0500 Received: from elephants.elehost.com ([216.66.27.132]:60447 "EHLO elephants.elehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727517AbfBNXEq (ORCPT ); Thu, 14 Feb 2019 18:04:46 -0500 X-Virus-Scanned: amavisd-new at elehost.com Received: from gnash (CPE00fc8d49d843-CM00fc8d49d840.cpe.net.cable.rogers.com [99.229.179.249]) (authenticated bits=0) by elephants.elehost.com (8.15.2/8.15.2) with ESMTPSA id x1EN4fAY040612 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 14 Feb 2019 18:04:41 -0500 (EST) (envelope-from rsbecker@nexbridge.com) From: "Randall S. Becker" To: "'Max Kirillov'" Cc: "'Johannes Schindelin via GitGitGadget'" , , "'Junio C Hamano'" References: <005401d4c4b3$147aa8c0$3d6ffa40$@nexbridge.com> <20190214223334.GE3064@jessie.local> In-Reply-To: <20190214223334.GE3064@jessie.local> Subject: RE: [PATCH 0/1] Fix hang in t5562, introduced in v2.21.0-rc1 Date: Thu, 14 Feb 2019 18:04:34 -0500 Message-ID: <005a01d4c4b9$a9c411e0$fd4c35a0$@nexbridge.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQJRGauSxHI8crErjTmvoq3vRhvADwFUx24oAoEs3RukyI+EsA== Content-Language: en-ca Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On February 14, 2019 17:34, Max Kirillov wrote: > To: Randall S. Becker > Cc: 'Johannes Schindelin via GitGitGadget' ; > git@vger.kernel.org; 'Junio C Hamano' ; 'Max Kirillov' > > 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.