From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24256 invoked by alias); 21 Mar 2018 17:36:53 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 24248 invoked by uid 89); 21 Mar 2018 17:36:52 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=dan, ancient, wake, Dan X-HELO: mail-pg0-f53.google.com Received: from mail-pg0-f53.google.com (HELO mail-pg0-f53.google.com) (74.125.83.53) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 21 Mar 2018 17:36:51 +0000 Received: by mail-pg0-f53.google.com with SMTP id a15so2206019pgn.5 for ; Wed, 21 Mar 2018 10:36:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:from:date:message-id:subject :to; bh=zy71qN8GSN6G11AILj/S5PZU0EwfLPPsBmtmtQf00KI=; b=kXA7J1gHOgGMBNRZtIAvAtxa7UGFoUDzeSJuQgrbjXyo6OZgg9j51EfMnPb+HkkLP7 7MoZqc+kJ31YJdt/pWuXZQxiNMvrmZ3UUNawIlRT9ImPikhuQbWEJ3fO3PKeqccrDT8L l/PhKDDwZh55P/+IZzeVF3sVhaO2uxt23KuxVBIAqptOPHr0Vt/7ENp9V1mT4i8U6Jco YLSxRhEg00fO7bMqmpgw8Edt6nIGb4g15i7azi2MAmN5Edat9sxADA0P4dY4yo0c5k8p mDh6h0oVhcTPFU6a+0MES2j4F48B4riqlJzZFfjclK8wd6kA8sq8Ha92Bu+yT5BSQJee 7d9Q== X-Gm-Message-State: AElRT7FI+TaMrFgPOkrzArBF3TWiK/6srKF3g4A++DYHuh9fqGefhBbJ tBGSuTppzbfyCXCEwyxtMnv2FrJhq4mrD1fnbBR9WQ== X-Google-Smtp-Source: AG47ELtiWQCIniCINqHcbDL0PiohLqxLvVzsAlpzsMQf/QiaarYZja/FG8H3mmD308iRfisQm63bakdYG7xP1yCVFBQ= X-Received: by 10.99.167.6 with SMTP id d6mr4614153pgf.287.1521653809212; Wed, 21 Mar 2018 10:36:49 -0700 (PDT) MIME-Version: 1.0 Received: by 10.100.154.86 with HTTP; Wed, 21 Mar 2018 10:36:48 -0700 (PDT) From: Dan Kegel Date: Wed, 21 Mar 2018 17:55:00 -0000 Message-ID: Subject: Odd hang in python waiting for child; strace wakes hung process? To: cygwin@cygwin.com Content-Type: text/plain; charset="UTF-8" X-IsSubscribed: yes X-SW-Source: 2018-03/txt/msg00331.txt.bz2 Dear Cygwin heros, I've been happily using cygwin to run buildbot slaves for several years. However, periodically they hang at the end of executing git. It kind of smells like SIGCHLD isn't delivered somehow. I shrugged it off as 'I'm using an ancient copy of twisted, it's my fault' for a long time, but recently updated to latest twisted, and it is still happening; today I came in and both of my windows buildbots are hung with it. While sniffing around at the edges of the problem, I noticed that the hung process would resume if I simply ran strace on it and then hit ^C to terminate strace. Here's the output of cygcheck and strace: http://kegel.com/linux/cyghang/ Older context at https://github.com/buildbot/buildbot/issues/3801 I'll surely hit this problem again soon; what other info should I gather? My next sensible step is to use an up to date version of buildbot's slave (I'm running a very old one at the moment), but it seems kind of fishy that strace could wake the process up. Thanks, Dan -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple