From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752047AbcFCHQC (ORCPT ); Fri, 3 Jun 2016 03:16:02 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:63775 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752013AbcFCHP7 (ORCPT ); Fri, 3 Jun 2016 03:15:59 -0400 Message-Id: <201606030715.u537FPjY031403@mx0a-001b2d01.pphosted.com> X-IBM-Helo: d06dlp03.portsmouth.uk.ibm.com X-IBM-MailFrom: heiko.carstens@de.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-s390@vger.kernel.org Date: Fri, 3 Jun 2016 09:15:44 +0200 From: Heiko Carstens To: Alfredo Alvarez Fernandez , Ingo Molnar , Peter Zijlstra Cc: Shuah Khan , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: [lockdep] chain_key collision check triggers MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16060307-0020-0000-0000-00000205EA67 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16060307-0021-0000-0000-00003C34982F X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-03_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=7 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606030081 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, the new lockdep chain_key collision detection code triggers quite reliably on s390, so it looks like we need a different iterate_chain_key() implementation? Actually there was already another report from Shuah Khan, which didn't get any replies as far as I can tell: https://lkml.org/lkml/2016/4/12/1080 Anyway, these are the chains on s390 which collided: [ 9550.753790] ====================== [ 9550.753791] [chain_key collision ] [ 9550.753793] 4.6.0-02644-gbf82442b7914 #2 Tainted: G W [ 9550.753795] ---------------------- [ 9550.753796] crond/2973: Hash chain already cached but the contents don't match! [ 9550.753798] Held locks:depth: 6 [ 9550.753800] class_idx:925 -> chain_key:000000000000039d (&sig->cred_guard_mutex){+.+.+.}, at: [<0000000000346bb4>] prepare_bprm_creds+0x44/0x98 [ 9550.753807] class_idx:944 -> chain_key:000000000073a3b0 (sb_writers#3){.+.+.+}, at: [<0000000000360aa2>] touch_atime+0x5a/0xd8 [ 9550.753814] class_idx:1064 -> chain_key:0000000e74760428 (jbd2_handle){+.+...}, at: [<0000000000442a20>] start_this_handle+0x470/0x558 [ 9550.753823] class_idx:843 -> chain_key:0001ce8ec085034b (&(&block->request_queue_lock)->rlock){..-.-.}, at: [<0000000000686c12>] blk_queue_bio+0x582/0x608 [ 9550.753830] class_idx:842 -> chain_key:39d1d810a069634a (&(&block->queue_lock)->rlock){+.-.-.}, at: [<00000000007df038>] do_dasd_request+0x38/0x60 [ 9550.753836] class_idx:850 -> chain_key:3b02140d2c694468 (dasd_global_profile.lock){..-.-.}, at: [<00000000007deeb8>] __dasd_process_request_queue+0x2a0/0x3e8 [ 9550.753841] Locks in cached chain:depth: 6 [ 9550.753844] class_idx:926 -> chain_key:000000000000039e (&type->i_mutex_dir_key){+.+.+.} [ 9550.753848] class_idx:944 -> chain_key:000000000073c3b0 (sb_writers#3){.+.+.+} [ 9550.753852] class_idx:1064 -> chain_key:0000000e78760428 (jbd2_handle){+.+...} [ 9550.753857] class_idx:843 -> chain_key:0001cf0ec085034b (&(&block->request_queue_lock)->rlock){..-.-.} [ 9550.753861] class_idx:842 -> chain_key:39e1d810a069634a (&(&block->queue_lock)->rlock){+.-.-.} [ 9550.753865] class_idx:852 -> chain_key:3b02140d2c694468 (&(&device->profile.lock)->rlock){..-.-.}