From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE198C282DA for ; Fri, 1 Feb 2019 16:12:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85FB1218EA for ; Fri, 1 Feb 2019 16:12:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730788AbfBAQMj (ORCPT ); Fri, 1 Feb 2019 11:12:39 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55792 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727897AbfBAQMh (ORCPT ); Fri, 1 Feb 2019 11:12:37 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x11Fugwb022918 for ; Fri, 1 Feb 2019 11:12:36 -0500 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qcs0sspy8-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 01 Feb 2019 11:12:36 -0500 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 1 Feb 2019 16:12:34 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (9.149.109.194) by e06smtp05.uk.ibm.com (192.168.101.135) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 1 Feb 2019 16:12:31 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x11GCTNK46858470 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 1 Feb 2019 16:12:29 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 84BC7A4060; Fri, 1 Feb 2019 16:12:29 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3E9D4A4067; Fri, 1 Feb 2019 16:12:29 +0000 (GMT) Received: from osiris (unknown [9.152.212.95]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Fri, 1 Feb 2019 16:12:29 +0000 (GMT) Date: Fri, 1 Feb 2019 17:12:27 +0100 From: Heiko Carstens To: Sebastian Sewior Cc: Thomas Gleixner , "Paul E. McKenney" , Peter Zijlstra , Ingo Molnar , Martin Schwidefsky , LKML , linux-s390@vger.kernel.org, Stefan Liebler Subject: Re: WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggerede References: <20190130210733.mg6aascw2gzl3oqz@linutronix.de> <20190130233557.GA4240@linux.ibm.com> <20190131165228.GA32680@osiris> <20190131170653.spnrxsiblkssleyd@linutronix.de> MIME-Version: 1.0 In-Reply-To: <20190131170653.spnrxsiblkssleyd@linutronix.de> X-TM-AS-GCONF: 00 x-cbid: 19020116-0020-0000-0000-000003105CCF X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19020116-0021-0000-0000-0000216160FB Message-Id: <20190201161227.GG3770@osiris> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit Content-Disposition: inline X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-01_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902010118 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 31, 2019 at 06:06:53PM +0100, Sebastian Sewior wrote: > On 2019-01-31 17:52:28 [+0100], Heiko Carstens wrote: > > ...nevertheless Stefan and I looked through the lovely disassembly of > > _pthread_mutex_lock_full() to verify if the compiler barriers are > > actually doing what they are supposed to do. The generated code > > however does look correct. > > So, it must be something different. > > would it make sense to use one locking function instead all three (lock, > try-lock, timed) in the test case to figure out if this is related to > one of the locking function? I tried all three variants, but it seems to be close to impossible to re-create then. I had a single fail when using only the trylock variant, but I wouldn't say that means anything. Only if all three variants run in parallel it seems to be quite reliably reproducible, even though sometimes it still takes an hour.