From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 83031 invoked by alias); 26 Jun 2017 12:27:54 -0000 Mailing-List: contact overseers-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: , Sender: overseers-owner@sourceware.org Received: (qmail 83012 invoked by uid 89); 26 Jun 2017 12:27:53 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=4.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SCAM_SUBJECT,SPF_PASS autolearn=no version=3.3.2 spammy=feeling X-HELO: mail-lf0-f46.google.com Received: from mail-lf0-f46.google.com (HELO mail-lf0-f46.google.com) (209.85.215.46) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 26 Jun 2017 12:27:51 +0000 Received: by mail-lf0-f46.google.com with SMTP id m77so59193777lfe.0 for ; Mon, 26 Jun 2017 05:27:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:from:subject:message-id:date:user-agent :mime-version:content-transfer-encoding:content-language; bh=K8OEGo0ufXS7LbMCkr1mXCKmU8Bju+m580IOrkHyCWk=; b=NDxBTL5FpBZ/pLSlSQJbO12BDmzsG4dgulCCbo++DworHe3slGDfo/YijVnn8W5f5y EdHmH/67yWuzz75srytWyqDJhmvro9QVjpbBJzX4zxmKUt6lctgsdejXL5uGcxpmiQQg AAYqs+gAaFfkdscnMBeAeJmWl/bXs5kNB/xytEhwZGGtPMhYE3DgeiTW4eRPZ47ERQRj L/hPf2yDYSBUYjCF/ZPKTrasGqVYzHrFx+cJPYSTp2aF1izCg3IKlOzxnq2ilz5OTBiH CN73vsujvCABZIFvgeYlfzZkudnHgSJgZySgX3C/5kYPa92GE9xXFmLOCQuUQm57wVdc HXpw== X-Gm-Message-State: AKS2vOxGG2Ch7TI5w2hJ7kgLJwa0YRkPGRg6KkGH0vxUD+6zaPu4tJ0z vqmgUmr/FQHd3BFfKAo= X-Received: by 10.46.84.77 with SMTP id y13mr6501466ljd.133.1498480068994; Mon, 26 Jun 2017 05:27:48 -0700 (PDT) Received: from [192.168.0.107] ([212.87.13.106]) by smtp.gmail.com with ESMTPSA id v28sm2833264ljd.17.2017.06.26.05.27.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Jun 2017 05:27:47 -0700 (PDT) To: overseers@gcc.gnu.org From: "Marcin M." Subject: Bugzilla account Message-ID: <11b878f8-3d81-1083-3ebb-6fc57063224e@gmail.com> Date: Mon, 26 Jun 2017 13:52:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2017-q2/txt/msg00137.txt.bz2 Hi! I'd like to report a bug against GCC. Can you please create an account for me? I attach the bug report in case I should: Hi! I have a feeling I've just found a bug in GCC 6.3.0 OpenMP implementation (new OpenMP 4.5 features) I'm running this code: https://gitlab.com/marmistrz/pw-brandes The parallelization is done by the following OpenMP directive: #pragma omp parallel for reduction(+: results[:n]) Where results is obtained as here: https://gitlab.com/marmistrz/pw-brandes/blob/master/brandes.cpp#L21 I get a segmentation fault when using the following dataset: http://snap.stanford.edu/data/com-LiveJournal.html (probably you need to remove the first 4 comment lines from it to work) or rather this dataset (both segfaults, but I tested more the second): http://snap.stanford.edu/data/web-Stanford.html The segmentation fault appears only on an Intel Xeon E5-2697 v3 (Haswell) processor, with 2 or more threads I have managed to successfully complete the web-Stanford testcase on an Intel i5-5200U processor, with 4 threads. The backtrace points to gomp_thread_start: #0 0x0000000000407006 in brandes () at /home/marmistrz/brandes/brandes.cpp:21 #1 0x00002aaaab31fc56 in gomp_thread_start () at ../../../gcc-6.3.0/libgomp/team.c:119 #2 0x00002aaaab753aa1 in start_thread () from /lib64/libpthread.so.0 #3 0x00002aaaaba51bcd in clone () from /lib64/libc.so.6 * linuxmodder_ is now known as linuxmodder It appears that the segfault at the very beginning of the thread start. Regards