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,URIBL_BLOCKED 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 C81C7C7112F for ; Mon, 21 Jan 2019 12:21:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A37122084A for ; Mon, 21 Jan 2019 12:21:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728573AbfAUMVk (ORCPT ); Mon, 21 Jan 2019 07:21:40 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:38146 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727926AbfAUMVk (ORCPT ); Mon, 21 Jan 2019 07:21:40 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x0LCJAX0136943 for ; Mon, 21 Jan 2019 07:21:39 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2q5bnxxwts-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 21 Jan 2019 07:21:38 -0500 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 21 Jan 2019 12:21:34 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0LCLXMI55902448 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 21 Jan 2019 12:21:33 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6534342049; Mon, 21 Jan 2019 12:21:33 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 288A742045; Mon, 21 Jan 2019 12:21:33 +0000 (GMT) Received: from osiris (unknown [9.152.212.95]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Mon, 21 Jan 2019 12:21:33 +0000 (GMT) Date: Mon, 21 Jan 2019 13:21:31 +0100 From: Heiko Carstens To: Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Martin Schwidefsky , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Stefan Liebler Subject: Re: WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggered References: <20181127081115.GB3625@osiris> <20181129112321.GB3449@osiris> MIME-Version: 1.0 In-Reply-To: <20181129112321.GB3449@osiris> X-TM-AS-GCONF: 00 x-cbid: 19012112-0012-0000-0000-000002EAD692 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19012112-0013-0000-0000-00002121FD4A Message-Id: <20190121122131.GG4020@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=2019-01-21_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 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-1901210097 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, [full quote below] Did you have any time to look into this yet? :) The warning is still reproducible. On Thu, Nov 29, 2018 at 12:23:21PM +0100, Heiko Carstens wrote: > On Wed, Nov 28, 2018 at 03:32:45PM +0100, Thomas Gleixner wrote: > > Heiko, > > > > On Tue, 27 Nov 2018, Heiko Carstens wrote: > > > > > with the glibc self-tests I was able to trigger the "this should not > > > happen" warning ;) below on s390 (with panic_on_warn=1 set). It looks > > > like it is hardly reproducible. > > > > Any idea which self-test triggered that? > > > > > This one happened with commit d146194f31c9 for compiling the kernel. > > > Config can be re-created with "make ARCH=s390 performance_defconfig". > > > > Which is not really helpful for people who do not own a s390. And no, I > > don't want one unless IBM pays the power bill as well :) > > > > > [ 649.596938] WARNING: CPU: 0 PID: 58886 at kernel/futex.c:1418 do_futex+0xa9a/0xc50 > > > [ 649.596946] Kernel panic - not syncing: panic_on_warn set ... > > > [ 649.596951] CPU: 0 PID: 58886 Comm: ld64.so.1 Not tainted 4.20.0-20181125.rc3.git0.d146194f31c9.300.fc29.s390x+git #1 > > > > That's ld64.so.1. Weird, but what do I know about glibc self tests. > > > > I still fail to see how that can happen, but I usually page out the futex > > horrors immediately. I'll keep staring at the code... > > I looked into the system dumps, and if I didn't screw up, then the > command line for both occurrences was > > /root/glibc-build/nptl/tst-robustpi8 > > And indeed, if I run only this test case in an endless loop and do > some parallel work (like kernel compile) it currently seems to be > possible to reproduce the warning: > > while true; do time ./testrun.sh nptl/tst-robustpi8 --direct ; done > > within the build directory of glibc (2.28). > > See > https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/tst-robustpi8.c;h=cbea3d6d77abb00be05ec7b466d8339c26dd2efb;hb=3c03baca37fdcb52c3881e653ca392bba7a99c2b > > which includes this one: > > https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/tst-robust8.c;h=9c636250d4cb0bcd6d802910e8f9ea31568bb73f;hb=3c03baca37fdcb52c3881e653ca392bba7a99c2b >