From patchwork Mon Jul 19 17:13:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Gushchin X-Patchwork-Id: 12386349 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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 81449C07E9D for ; Mon, 19 Jul 2021 17:18:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 666D760FED for ; Mon, 19 Jul 2021 17:18:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352114AbhGSQhq (ORCPT ); Mon, 19 Jul 2021 12:37:46 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:39054 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352538AbhGSQdX (ORCPT ); Mon, 19 Jul 2021 12:33:23 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 16JHAGZS001041 for ; Mon, 19 Jul 2021 10:14:02 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=FFXXpPy+b2KsSMD00iCifAXCcNS5nJJ6e2fpWpLQVYk=; b=gxgmAPN4Ndo/A1Sfe9KbkAkOlAcU28ZW2lnlTIIMBWatL5/ugbxayN9sFio/F5aCKvGj IQzdX0TtTN/qiC3zGpdRZtm3OVOm8GkmmlDc5Iodhnm7zgLKdyk7zybX8F2DRK1OUrBl Vf25OAoVBnqCl5IkHFotz/9WEura7jiG/io= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 39vytc459p-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 19 Jul 2021 10:14:02 -0700 Received: from intmgw003.48.prn1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 19 Jul 2021 10:14:00 -0700 Received: by devvm3388.prn0.facebook.com (Postfix, from userid 111017) id 780349993B80; Mon, 19 Jul 2021 10:13:51 -0700 (PDT) From: Roman Gushchin To: Andrew Morton CC: , , Jan Kara , Dave Chinner , Roman Gushchin , Murphy Zhou , "Darrick J . Wong" , Matthew Wilcox Subject: [PATCH] writeback, cgroup: do not reparent dax inodes Date: Mon, 19 Jul 2021 10:13:50 -0700 Message-ID: <20210719171350.3876830-1-guro@fb.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: n82ssd9LtPDcK6BY_RsrOQPNtarvmLck X-Proofpoint-ORIG-GUID: n82ssd9LtPDcK6BY_RsrOQPNtarvmLck X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-19_09:2021-07-19,2021-07-19 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 spamscore=0 lowpriorityscore=0 malwarescore=0 priorityscore=1501 impostorscore=0 mlxscore=0 phishscore=0 adultscore=0 clxscore=1015 mlxlogscore=905 suspectscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107190100 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The inode switching code is not suited for dax inodes. An attempt to switch a dax inode to a parent writeback structure (as a part of a writeback cleanup procedure) results in a panic like this: [ 987.071651] run fstests generic/270 at 2021-07-15 05:54:02 [ 988.704940] XFS (pmem0p2): EXPERIMENTAL big timestamp feature in use. Use at your own risk! [ 988.746847] XFS (pmem0p2): DAX enabled. Warning: EXPERIMENTAL, use at your own risk [ 988.786070] XFS (pmem0p2): EXPERIMENTAL inode btree counters feature in use. Use at your own risk! [ 988.828639] XFS (pmem0p2): Mounting V5 Filesystem [ 988.854019] XFS (pmem0p2): Ending clean mount [ 988.874550] XFS (pmem0p2): Quotacheck needed: Please wait. [ 988.900618] XFS (pmem0p2): Quotacheck: Done. [ 989.090783] XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks) [ 989.092751] XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks) [ 989.092962] XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks) [ 1010.105586] BUG: unable to handle page fault for address: 0000000005b0f669 [ 1010.141817] #PF: supervisor read access in kernel mode [ 1010.167824] #PF: error_code(0x0000) - not-present page [ 1010.191499] PGD 0 P4D 0 [ 1010.203346] Oops: 0000 [#1] SMP PTI [ 1010.219596] CPU: 13 PID: 10479 Comm: kworker/13:16 Not tainted 5.14.0-rc1-master-8096acd7442e+ #8 [ 1010.260441] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 09/13/2016 [ 1010.297792] Workqueue: inode_switch_wbs inode_switch_wbs_work_fn [ 1010.324832] RIP: 0010:inode_do_switch_wbs+0xaf/0x470 [ 1010.347261] Code: 00 30 0f 85 c1 03 00 00 0f 1f 44 00 00 31 d2 48 c7 c6 ff ff ff ff 48 8d 7c 24 08 e8 eb 49 1a 00 48 85 c0 74 4a bb ff ff ff ff <48> 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 00 a8 08 0f 85 [ 1010.434307] RSP: 0018:ffff9c66691abdc8 EFLAGS: 00010002 [ 1010.457795] RAX: 0000000005b0f661 RBX: 00000000ffffffff RCX: ffff89e6a21382b0 [ 1010.489922] RDX: 0000000000000001 RSI: ffff89e350230248 RDI: ffffffffffffffff [ 1010.522085] RBP: ffff89e681d19400 R08: 0000000000000000 R09: 0000000000000228 [ 1010.554234] R10: ffffffffffffffff R11: ffffffffffffffc0 R12: ffff89e6a2138130 [ 1010.586414] R13: ffff89e316af7400 R14: ffff89e316af6e78 R15: ffff89e6a21382b0 [ 1010.619394] FS: 0000000000000000(0000) GS:ffff89ee5fb40000(0000) knlGS:0000000000000000 [ 1010.658874] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1010.688085] CR2: 0000000005b0f669 CR3: 0000000cb2410004 CR4: 00000000001706e0 [ 1010.722129] Call Trace: [ 1010.733132] inode_switch_wbs_work_fn+0xb6/0x2a0 [ 1010.754121] process_one_work+0x1e6/0x380 [ 1010.772512] worker_thread+0x53/0x3d0 [ 1010.789221] ? process_one_work+0x380/0x380 [ 1010.807964] kthread+0x10f/0x130 [ 1010.822043] ? set_kthread_struct+0x40/0x40 [ 1010.840818] ret_from_fork+0x22/0x30 [ 1010.856851] Modules linked in: xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nft_counter nf_tables nfnetlink bridge stp llc rfkill sunrpc intel_rapl_msr intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel ipmi_ssif kvm mgag200 i2c_algo_bit iTCO_wdt irqbypass drm_kms_helper iTCO_vendor_support acpi_ipmi rapl syscopyarea sysfillrect intel_cstate ipmi_si sysimgblt ioatdma dax_pmem_compat fb_sys_fops ipmi_devintf device_dax i2c_i801 pcspkr intel_uncore hpilo nd_pmem cec dax_pmem_core dca i2c_smbus acpi_tad lpc_ich ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sd_mod t10_pi crct10dif_pclmul crc32_pclmul crc32c_intel tg3 ghash_clmulni_intel serio_raw hpsa hpwdt scsi_transport_sas wmi dm_mirror dm_region_hash dm_log dm_mod [ 1011.200864] CR2: 0000000005b0f669 [ 1011.215700] ---[ end trace ed2105faff8384f3 ]--- [ 1011.241727] RIP: 0010:inode_do_switch_wbs+0xaf/0x470 [ 1011.264306] Code: 00 30 0f 85 c1 03 00 00 0f 1f 44 00 00 31 d2 48 c7 c6 ff ff ff ff 48 8d 7c 24 08 e8 eb 49 1a 00 48 85 c0 74 4a bb ff ff ff ff <48> 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 00 a8 08 0f 85 [ 1011.348821] RSP: 0018:ffff9c66691abdc8 EFLAGS: 00010002 [ 1011.372734] RAX: 0000000005b0f661 RBX: 00000000ffffffff RCX: ffff89e6a21382b0 [ 1011.405826] RDX: 0000000000000001 RSI: ffff89e350230248 RDI: ffffffffffffffff [ 1011.437852] RBP: ffff89e681d19400 R08: 0000000000000000 R09: 0000000000000228 [ 1011.469926] R10: ffffffffffffffff R11: ffffffffffffffc0 R12: ffff89e6a2138130 [ 1011.502179] R13: ffff89e316af7400 R14: ffff89e316af6e78 R15: ffff89e6a21382b0 [ 1011.534233] FS: 0000000000000000(0000) GS:ffff89ee5fb40000(0000) knlGS:0000000000000000 [ 1011.571247] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1011.597063] CR2: 0000000005b0f669 CR3: 0000000cb2410004 CR4: 00000000001706e0 [ 1011.629160] Kernel panic - not syncing: Fatal exception [ 1011.653802] Kernel Offset: 0x15200000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 1011.713723] ---[ end Kernel panic - not syncing: Fatal exception ]--- The crash happens on an attempt to iterate over attached pagecache pages and check the dirty flag: a dax inode's xarray contains pfn's instead of generic struct page pointers. Fix the problem by bailing out (with the false return value) of inode_prepare_sbs_switch() if a dax inode is passed. Fixes: c22d70a162d3 ("writeback, cgroup: release dying cgwbs by switching attached inodes") Signed-off-by: Roman Gushchin Reported-by: Murphy Zhou Reported-by: Darrick J. Wong Tested-by: Murphy Zhou Cc: Matthew Wilcox Tested-by: Darrick J. Wong Acked-by: Matthew Wilcox (Oracle) --- fs/fs-writeback.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 06d04a74ab6c..4c3370548982 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -521,6 +521,9 @@ static bool inode_prepare_wbs_switch(struct inode *inode, */ smp_mb(); + if (IS_DAX(inode)) + return false; + /* while holding I_WB_SWITCH, no one else can update the association */ spin_lock(&inode->i_lock); if (!(inode->i_sb->s_flags & SB_ACTIVE) ||