From patchwork Wed Jan 11 04:43:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dai Ngo X-Patchwork-Id: 13096011 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FB64C46467 for ; Wed, 11 Jan 2023 04:44:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229986AbjAKEoB (ORCPT ); Tue, 10 Jan 2023 23:44:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229819AbjAKEoA (ORCPT ); Tue, 10 Jan 2023 23:44:00 -0500 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49BBB6396 for ; Tue, 10 Jan 2023 20:43:58 -0800 (PST) Received: from pps.filterd (m0333521.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 30B31QWq017391; Wed, 11 Jan 2023 04:43:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2022-7-12; bh=ilUc5kyQSkb2Oo0cvQtpqQ5xq6YCJs8EH6KQ/VjfV0U=; b=TKvC2TwLY9B4BZVMtRlSSEodIEM7/iHSbt+D3eTEOnNdqxHOucT0P1Kk0t/z9jj43Hq9 1oltPqA6d4/Ouz40Xhh2VZqsrjXIkuqdogj/VB7gBjVHV8838Rbfh/khJcIjoYsMOe43 2Jf4r7RY428oELRhLR9JFKTWSLAGKvVECO30Ou4a44ZdlIDYRJpA4763m2DQ2mkPyIih GvUdilwXX9VpQGU9wOvWncX0c3yDIfXGc6LGpGP6SVjtV+CMZMvkSX47TqXmpIBOWNHt jUyaa37nKT4GsmEtHv3tEmwiQjXTPGuRyOwYUASaU2bZvuMgzdbX0bfJUyngbt4UpQHU /A== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3n173bj014-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Jan 2023 04:43:52 +0000 Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 30B41WXJ009269; Wed, 11 Jan 2023 04:43:51 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3n1k4np2kh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Jan 2023 04:43:51 +0000 Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 30B4hoIO023362; Wed, 11 Jan 2023 04:43:50 GMT Received: from ca-common-hq.us.oracle.com (ca-common-hq.us.oracle.com [10.211.9.209]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 3n1k4np2k4-1; Wed, 11 Jan 2023 04:43:50 +0000 From: Dai Ngo To: chuck.lever@oracle.com, jlayton@kernel.org Cc: efault@gmx.de, linux-nfs@vger.kernel.org Subject: [PATCH v2 1/1] NFSD: fix WARN_ON_ONCE in __queue_delayed_work Date: Tue, 10 Jan 2023 20:43:41 -0800 Message-Id: <1673412221-8037-1-git-send-email-dai.ngo@oracle.com> X-Mailer: git-send-email 1.8.3.1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2023-01-11_01,2023-01-10_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 adultscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 phishscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301110035 X-Proofpoint-GUID: D1g5d54zjtYTCIXq6t3-NkBSml4tJp_Y X-Proofpoint-ORIG-GUID: D1g5d54zjtYTCIXq6t3-NkBSml4tJp_Y Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Currently nfsd4_state_shrinker_worker can be schduled multiple times from nfsd4_state_shrinker_count when memory is low. This causes the WARN_ON_ONCE in __queue_delayed_work to trigger. This patch allows only one instance of nfsd4_state_shrinker_worker at a time using the nfsd_shrinker_active flag, protected by the client_lock. Replace mod_delayed_work in nfsd4_state_shrinker_count with queue_work. Change nfsd_shrinker_work from delayed_work to work_struct since we don't use the delay. Cancel work_struct nfsd_shrinker_work after unregistering shrinker in nfs4_state_shutdown_net Fixes: 44df6f439a17 ("NFSD: add delegation reaper to react to low memory condition") Reported-by: Mike Galbraith Signed-off-by: Dai Ngo --- v2: . Replace mod_delayed_work in nfsd4_state_shrinker_count with queue_work . Change nfsd_shrinker_work from delayed_work to work_struct . Cancel work_struct nfsd_shrinker_work after unregistering shrinker fs/nfsd/netns.h | 3 ++- fs/nfsd/nfs4state.c | 22 +++++++++++++++++----- 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 8c854ba3285b..b0c7b657324b 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -195,7 +195,8 @@ struct nfsd_net { atomic_t nfsd_courtesy_clients; struct shrinker nfsd_client_shrinker; - struct delayed_work nfsd_shrinker_work; + struct work_struct nfsd_shrinker_work; + bool nfsd_shrinker_active; }; /* Simple check to find out if a given net was properly initialized */ diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index a7cfefd7c205..6508f9c79315 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4407,11 +4407,20 @@ nfsd4_state_shrinker_count(struct shrinker *shrink, struct shrink_control *sc) struct nfsd_net *nn = container_of(shrink, struct nfsd_net, nfsd_client_shrinker); + spin_lock(&nn->client_lock); + if (nn->nfsd_shrinker_active) { + spin_unlock(&nn->client_lock); + return 0; + } count = atomic_read(&nn->nfsd_courtesy_clients); if (!count) count = atomic_long_read(&num_delegations); - if (count) - mod_delayed_work(laundry_wq, &nn->nfsd_shrinker_work, 0); + if (count) { + nn->nfsd_shrinker_active = true; + spin_unlock(&nn->client_lock); + queue_work(laundry_wq, &nn->nfsd_shrinker_work); + } else + spin_unlock(&nn->client_lock); return (unsigned long)count; } @@ -6233,12 +6242,14 @@ deleg_reaper(struct nfsd_net *nn) static void nfsd4_state_shrinker_worker(struct work_struct *work) { - struct delayed_work *dwork = to_delayed_work(work); - struct nfsd_net *nn = container_of(dwork, struct nfsd_net, + struct nfsd_net *nn = container_of(work, struct nfsd_net, nfsd_shrinker_work); courtesy_client_reaper(nn); deleg_reaper(nn); + spin_lock(&nn->client_lock); + nn->nfsd_shrinker_active = 0; + spin_unlock(&nn->client_lock); } static inline __be32 nfs4_check_fh(struct svc_fh *fhp, struct nfs4_stid *stp) @@ -8064,7 +8075,7 @@ static int nfs4_state_create_net(struct net *net) INIT_LIST_HEAD(&nn->blocked_locks_lru); INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main); - INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker); + INIT_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker); get_net(net); nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan; @@ -8171,6 +8182,7 @@ nfs4_state_shutdown_net(struct net *net) struct nfsd_net *nn = net_generic(net, nfsd_net_id); unregister_shrinker(&nn->nfsd_client_shrinker); + cancel_work(&nn->nfsd_shrinker_work); cancel_delayed_work_sync(&nn->laundromat_work); locks_end_grace(&nn->nfsd4_manager);