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=-9.8 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, 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 E9DAEC47409 for ; Fri, 13 Dec 2019 22:24:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B9ACA22527 for ; Fri, 13 Dec 2019 22:24:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="F9NeOTKw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726757AbfLMWY1 (ORCPT ); Fri, 13 Dec 2019 17:24:27 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:35498 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726345AbfLMWY1 (ORCPT ); Fri, 13 Dec 2019 17:24:27 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xBDMOO28155344; Fri, 13 Dec 2019 22:24:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2019-08-05; bh=QUIXsOoy+ec+JNrRBMR7QrIHAGWn0KFprylci6Z6A0U=; b=F9NeOTKwf7Hz2yjtNi/QZXhCH3jMbEZGTH1RR1lom6OmoPuOrBhofOtm2T5IITwJgFKS nZLiXtW5ApPPbbgWlJdovxw3zHEjo6kYkBcXQrYsSHMdd24uQrorm/tGsTgs+Ez7o+Lw KQM16Tk4AnyZxwkL49B9ekJC8R/EfwTrQuYz/uDvuv7l1s7Sphm/FHDRpWfgYC9AOWRK brgSMamQf7rHCAGxKRAIWg5j8L+UyLjNvXEWH5SyW3ogYfaF8B3JqzDxhASfYDgO+X4X tTUUHJe+8wmZD+6KSCmnBLuqVg3hJiJGKYWEsVmP9MHo+0cXtyA7tZGdbro0cdLS4jWy UQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2120.oracle.com with ESMTP id 2wr41qum4d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Dec 2019 22:24:24 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xBDMNa9C077548; Fri, 13 Dec 2019 22:24:22 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3020.oracle.com with ESMTP id 2wvdwr9hhf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Dec 2019 22:24:22 +0000 Received: from abhmp0008.oracle.com (abhmp0008.oracle.com [141.146.116.14]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xBDMOMNs013254; Fri, 13 Dec 2019 22:24:22 GMT Received: from jubi-laptop.us.oracle.com (/10.211.46.28) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 13 Dec 2019 14:24:22 -0800 From: Junxiao Bi To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: viro@zeniv.linux.org.uk Subject: [PATCH] vfs: stop shrinker while fs is freezed Date: Fri, 13 Dec 2019 14:24:40 -0800 Message-Id: <20191213222440.11519-1-junxiao.bi@oracle.com> X-Mailer: git-send-email 2.17.1 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9470 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=976 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912130158 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9470 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 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-1912130158 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Shrinker could be blocked by freeze while dropping the last reference of some inode that had been removed. As "s_umount" lock was acquired by the Shrinker before blocked, the thaw will hung by this lock. This caused a deadlock. crash7latest> set 132 PID: 132 COMMAND: "kswapd0:0" TASK: ffff9cdc9dfb5f00 [THREAD_INFO: ffff9cdc9dfb5f00] CPU: 6 STATE: TASK_UNINTERRUPTIBLE crash7latest> bt PID: 132 TASK: ffff9cdc9dfb5f00 CPU: 6 COMMAND: "kswapd0:0" #0 [ffffaa5d075bf900] __schedule at ffffffff8186487c #1 [ffffaa5d075bf998] schedule at ffffffff81864e96 #2 [ffffaa5d075bf9b0] rwsem_down_read_failed at ffffffff818689ee #3 [ffffaa5d075bfa40] call_rwsem_down_read_failed at ffffffff81859308 #4 [ffffaa5d075bfa90] __percpu_down_read at ffffffff810ebd38 #5 [ffffaa5d075bfab0] __sb_start_write at ffffffff812859ef #6 [ffffaa5d075bfad0] xfs_trans_alloc at ffffffffc07ebe9c [xfs] #7 [ffffaa5d075bfb18] xfs_free_eofblocks at ffffffffc07c39d1 [xfs] #8 [ffffaa5d075bfb80] xfs_inactive at ffffffffc07de878 [xfs] #9 [ffffaa5d075bfba0] __dta_xfs_fs_destroy_inode_3543 at ffffffffc07e885e [xfs] #10 [ffffaa5d075bfbd0] destroy_inode at ffffffff812a25de #11 [ffffaa5d075bfbe8] evict at ffffffff812a2b73 #12 [ffffaa5d075bfc10] dispose_list at ffffffff812a2c1d #13 [ffffaa5d075bfc38] prune_icache_sb at ffffffff812a421a #14 [ffffaa5d075bfc70] super_cache_scan at ffffffff812870a1 #15 [ffffaa5d075bfcc8] shrink_slab at ffffffff811eebb3 #16 [ffffaa5d075bfdb0] shrink_node at ffffffff811f4788 #17 [ffffaa5d075bfe38] kswapd at ffffffff811f58c3 #18 [ffffaa5d075bff08] kthread at ffffffff810b75d5 #19 [ffffaa5d075bff50] ret_from_fork at ffffffff81a0035e crash7latest> set 31060 PID: 31060 COMMAND: "safefreeze" TASK: ffff9cd292868000 [THREAD_INFO: ffff9cd292868000] CPU: 2 STATE: TASK_UNINTERRUPTIBLE crash7latest> bt PID: 31060 TASK: ffff9cd292868000 CPU: 2 COMMAND: "safefreeze" #0 [ffffaa5d10047c90] __schedule at ffffffff8186487c #1 [ffffaa5d10047d28] schedule at ffffffff81864e96 #2 [ffffaa5d10047d40] rwsem_down_write_failed at ffffffff81868f18 #3 [ffffaa5d10047dd8] call_rwsem_down_write_failed at ffffffff81859367 #4 [ffffaa5d10047e20] down_write at ffffffff81867cfd #5 [ffffaa5d10047e38] thaw_super at ffffffff81285d2d #6 [ffffaa5d10047e60] do_vfs_ioctl at ffffffff81299566 #7 [ffffaa5d10047ee8] sys_ioctl at ffffffff81299709 #8 [ffffaa5d10047f28] do_syscall_64 at ffffffff81003949 #9 [ffffaa5d10047f50] entry_SYSCALL_64_after_hwframe at ffffffff81a001ad RIP: 0000000000453d67 RSP: 00007ffff9c1ce78 RFLAGS: 00000206 RAX: ffffffffffffffda RBX: 0000000001cbe92c RCX: 0000000000453d67 RDX: 0000000000000000 RSI: 00000000c0045878 RDI: 0000000000000014 RBP: 00007ffff9c1cf80 R8: 0000000000000000 R9: 0000000000000012 R10: 0000000000000008 R11: 0000000000000206 R12: 0000000000401fb0 R13: 0000000000402040 R14: 0000000000000000 R15: 0000000000000000 ORIG_RAX: 0000000000000010 CS: 0033 SS: 002b Signed-off-by: Junxiao Bi --- fs/super.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/super.c b/fs/super.c index cfadab2cbf35..adc18652302b 100644 --- a/fs/super.c +++ b/fs/super.c @@ -80,6 +80,11 @@ static unsigned long super_cache_scan(struct shrinker *shrink, if (!trylock_super(sb)) return SHRINK_STOP; + if (sb->s_writers.frozen != SB_UNFROZEN) { + up_read(&sb->s_umount); + return SHRINK_STOP; + } + if (sb->s_op->nr_cached_objects) fs_objects = sb->s_op->nr_cached_objects(sb, sc); -- 2.17.1