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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 F39DBC43603 for ; Wed, 18 Dec 2019 23:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B628B2176D for ; Wed, 18 Dec 2019 23:21:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="b7nwrLtM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726518AbfLRXVM (ORCPT ); Wed, 18 Dec 2019 18:21:12 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:60792 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbfLRXVM (ORCPT ); Wed, 18 Dec 2019 18:21:12 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xBIN9p3n113284; Wed, 18 Dec 2019 23:20:59 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2019-08-05; bh=8hazM7CeF4K47Rh8XmW2jWUImNMg1yZHhsjs63LcOEE=; b=b7nwrLtMcykLAuGtxi7o2zlSED3gSlOVzYgyTPCCuzSFY/eMoIi32LmcYLx1IoKt6GIP nmGldQQTOVqI3pGbWepJxjwrHOngEuCNcE89sCmb5x5Xtb5HQmSoRYyUxfaCMdTbXZ+Y tsFh64EKthIV/prru/p1Sg8iK0TuXia6eQ8RfUlCsDfMTmyoCZjQGXr/eHGz3uiSpHr7 oaKer3eLo7JTj0+l1RCDbNeK48RxNJPXnvj1f9uc+heUT8uXaTtk0nE6+VQ2SqGxumQj /S9ZpUCcEm77V/pA508SA8Ws+deIWeAW1uQkTids6MbHqf5++RKZn+0RPS6Ioaxh1tSk Qg== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 2wvq5urs6u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 Dec 2019 23:20:59 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xBIN9nQo108431; Wed, 18 Dec 2019 23:20:59 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 2wyk3by1cs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 Dec 2019 23:20:59 +0000 Received: from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id xBINKwtL024557; Wed, 18 Dec 2019 23:20:58 GMT Received: from anon-dhcp-152.1015granger.net (/68.61.232.219) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 18 Dec 2019 15:20:57 -0800 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: Re: CPU lockup in or near new filecache code From: Chuck Lever In-Reply-To: Date: Wed, 18 Dec 2019 18:20:56 -0500 Cc: Bruce Fields , Jeff Layton , Linux NFS Mailing List Content-Transfer-Encoding: quoted-printable Message-Id: <980CB8E4-0E7F-4F1D-B223-81176BE15A39@oracle.com> References: <9977648B-7D14-42EB-BD4A-CBD041A0C21A@oracle.com> <3af633a4016a183a930a44e3287f9da230711629.camel@hammerspace.com> To: Trond Myklebust X-Mailer: Apple Mail (2.3445.104.11) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9475 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912180173 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9475 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default 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=8.0.1-1911140001 definitions=main-1912180173 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org > On Dec 13, 2019, at 3:12 PM, Trond Myklebust = wrote: >=20 > On Wed, 2019-12-11 at 15:01 -0500, Chuck Lever wrote: >> OK, I finally got a hit. It took a long time. I've seen this >> particular >> stack trace before, several times. >>=20 >> Dec 11 14:58:34 klimt kernel: watchdog: BUG: soft lockup - CPU#0 >> stuck for 22s! [nfsd:2005] >> Dec 11 14:58:34 klimt kernel: Modules linked in: rpcsec_gss_krb5 >> ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager >> ocfs2_stackglue ib_umad ib_ipoib mlx4_ib sb_edac x86_pkg_temp_thermal >> kvm_intel coretemp kvm irqbypass crct10dif_pclmul crc32_pclmul >> ghash_clmulni_intel iTCO_wdt ext4 iTCO_vendor_support aesni_intel >> mbcache jbd2 glue_helper rpcrdma crypto_simd cryptd rdma_ucm ib_iser >> rdma_cm pcspkr iw_cm ib_cm mei_me raid0 libiscsi lpc_ich mei sg >> scsi_transport_iscsi i2c_i801 mfd_core wmi ipmi_si ipmi_devintf >> ipmi_msghandler ioatdma acpi_power_meter nfsd nfs_acl lockd >> auth_rpcgss grace sunrpc ip_tables xfs libcrc32c mlx4_en sr_mod >> sd_mod cdrom qedr ast drm_vram_helper drm_ttm_helper ttm crc32c_intel >> drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm igb >> dca i2c_algo_bit i2c_core mlx4_core ahci libahci libata nvme >> nvme_core qede qed dm_mirror dm_region_hash dm_log dm_mod crc8 >> ib_uverbs dax ib_core >> Dec 11 14:58:34 klimt kernel: CPU: 0 PID: 2005 Comm: nfsd Tainted: >> G W 5.5.0-rc1-00003-g170e7adc2317 #1401 >> Dec 11 14:58:34 klimt kernel: Hardware name: Supermicro Super >> Server/X10SRL-F, BIOS 1.0c 09/09/2015 >> Dec 11 14:58:34 klimt kernel: RIP: 0010:__srcu_read_lock+0x23/0x24 >> Dec 11 14:58:34 klimt kernel: Code: 07 00 0f 1f 40 00 c3 0f 1f 44 00 >> 00 8b 87 c8 c3 00 00 48 8b 97 f0 c3 00 00 83 e0 01 48 63 c8 65 48 ff >> 04 ca f0 83 44 24 fc 00 0f 1f 44 00 00 f0 83 44 24 fc 00 48 63 >> f6 48 8b 87 f0 c3 00 00 >> Dec 11 14:58:34 klimt kernel: RSP: 0018:ffffc90001d97bd0 EFLAGS: >> 00000246 ORIG_RAX: ffffffffffffff13 >> Dec 11 14:58:34 klimt kernel: RAX: 0000000000000001 RBX: >> ffff888830d0eb78 RCX: 0000000000000001 >> Dec 11 14:58:34 klimt kernel: RDX: 0000000000030f00 RSI: >> ffff888853f4da00 RDI: ffffffff82815a40 >> Dec 11 14:58:34 klimt kernel: RBP: ffff88883112d828 R08: >> ffff888843540000 R09: ffffffff8121d707 >> Dec 11 14:58:34 klimt kernel: R10: ffffc90001d97bf0 R11: >> 0000000000001b84 R12: ffff888853f4da00 >> Dec 11 14:58:34 klimt kernel: R13: ffff8888132a1410 R14: >> ffff88883112d7e0 R15: 00000000ffffffef >> Dec 11 14:58:34 klimt kernel: FS: 0000000000000000(0000) >> GS:ffff88885fc00000(0000) knlGS:0000000000000000 >> Dec 11 14:58:34 klimt kernel: CS: 0010 DS: 0000 ES: 0000 CR0: >> 0000000080050033 >> Dec 11 14:58:34 klimt kernel: CR2: 00007f2d6a2d8000 CR3: >> 0000000859b38004 CR4: 00000000001606f0 >> Dec 11 14:58:34 klimt kernel: Call Trace: >> Dec 11 14:58:34 klimt kernel: fsnotify_grab_connector+0x16/0x4f >> Dec 11 14:58:34 klimt kernel: fsnotify_find_mark+0x11/0x6a >> Dec 11 14:58:34 klimt kernel: nfsd_file_acquire+0x3a9/0x5b2 [nfsd] >> Dec 11 14:58:34 klimt kernel: nfs4_get_vfs_file+0x14c/0x20f [nfsd] >> Dec 11 14:58:34 klimt kernel: nfsd4_process_open2+0xcd6/0xd98 [nfsd] >> Dec 11 14:58:34 klimt kernel: ? fh_verify+0x42e/0x4ef [nfsd] >> Dec 11 14:58:34 klimt kernel: ? nfsd4_process_open1+0x233/0x29d >> [nfsd] >> Dec 11 14:58:34 klimt kernel: nfsd4_open+0x500/0x5cb [nfsd] >> Dec 11 14:58:34 klimt kernel: nfsd4_proc_compound+0x32a/0x5c7 [nfsd] >> Dec 11 14:58:34 klimt kernel: nfsd_dispatch+0x102/0x1e2 [nfsd] >> Dec 11 14:58:34 klimt kernel: svc_process_common+0x3b3/0x65d [sunrpc] >> Dec 11 14:58:34 klimt kernel: ? svc_xprt_put+0x12/0x21 [sunrpc] >> Dec 11 14:58:34 klimt kernel: ? nfsd_svc+0x2be/0x2be [nfsd] >> Dec 11 14:58:34 klimt kernel: ? nfsd_destroy+0x51/0x51 [nfsd] >> Dec 11 14:58:34 klimt kernel: svc_process+0xf6/0x115 [sunrpc] >> Dec 11 14:58:34 klimt kernel: nfsd+0xf2/0x149 [nfsd] >> Dec 11 14:58:34 klimt kernel: kthread+0xf6/0xfb >> Dec 11 14:58:34 klimt kernel: ? kthread_queue_delayed_work+0x74/0x74 >> Dec 11 14:58:34 klimt kernel: ret_from_fork+0x3a/0x50 >>=20 >=20 > Does something like the following help? >=20 > 8<--------------------------------------------------- > =46rom caf515c82ed572e4f92ac8293e5da4818da0c6ce Mon Sep 17 00:00:00 = 2001 > From: Trond Myklebust > Date: Fri, 13 Dec 2019 15:07:33 -0500 > Subject: [PATCH] nfsd: Fix a soft lockup race in > nfsd_file_mark_find_or_create() >=20 > If nfsd_file_mark_find_or_create() keeps winning the race for the > nfsd_file_fsnotify_group->mark_mutex against nfsd_file_mark_put() > then it can soft lock up, since fsnotify_add_inode_mark() ends > up always finding an existing entry. >=20 > Signed-off-by: Trond Myklebust > --- > fs/nfsd/filecache.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) >=20 > diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c > index 9c2b29e07975..f275c11c4e28 100644 > --- a/fs/nfsd/filecache.c > +++ b/fs/nfsd/filecache.c > @@ -132,9 +132,13 @@ nfsd_file_mark_find_or_create(struct nfsd_file = *nf) > struct nfsd_file_mark, > nfm_mark)); > = mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); > - fsnotify_put_mark(mark); > - if (likely(nfm)) > + if (nfm) { > + fsnotify_put_mark(mark); > break; > + } > + /* Avoid soft lockup race with = nfsd_file_mark_put() */ > + fsnotify_destroy_mark(mark, = nfsd_file_fsnotify_group); > + fsnotify_put_mark(mark); > } else > = mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); >=20 I've tried to reproduce the lockup for three days with this patch applied to my server. No lockup. Tested-by: Chuck Lever -- Chuck Lever