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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0817BC4332F for ; Thu, 28 Apr 2022 12:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346673AbiD1MzI (ORCPT ); Thu, 28 Apr 2022 08:55:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232445AbiD1MzG (ORCPT ); Thu, 28 Apr 2022 08:55:06 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB025AC068; Thu, 28 Apr 2022 05:51:49 -0700 (PDT) Received: from kwepemi100003.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4KpwRT7587zGp2D; Thu, 28 Apr 2022 20:49:09 +0800 (CST) Received: from kwepemm600001.china.huawei.com (7.193.23.3) by kwepemi100003.china.huawei.com (7.221.188.122) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 28 Apr 2022 20:51:47 +0800 Received: from [10.174.176.245] (10.174.176.245) by kwepemm600001.china.huawei.com (7.193.23.3) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 28 Apr 2022 20:51:46 +0800 Message-ID: <3bf34932-1444-b914-3610-422de259d60d@huawei.com> Date: Thu, 28 Apr 2022 20:51:46 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH net] SUNRPC: Fix local socket leak in xs_local_setup_socket() From: "wanghai (M)" To: Trond Myklebust , "anna@kernel.org" , "pabeni@redhat.com" , "davem@davemloft.net" , "chuck.lever@oracle.com" , "kuba@kernel.org" CC: "linux-nfs@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20220426132011.25418-1-wanghai38@huawei.com> <2edb137e-b12f-e912-8c2b-9ad3737a0182@huawei.com> In-Reply-To: <2edb137e-b12f-e912-8c2b-9ad3737a0182@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.176.245] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600001.china.huawei.com (7.193.23.3) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/4/27 15:15, wanghai (M) 写道: > > 在 2022/4/27 2:51, Trond Myklebust 写道: >> On Tue, 2022-04-26 at 21:20 +0800, Wang Hai wrote: >>> If the connection to a local endpoint in xs_local_setup_socket() >>> fails, >>> fput() is missing in the error path, which will result in a socket >>> leak. >>> It can be reproduced in simple script below. >>> >>> while true >>> do >>>          systemctl stop rpcbind.service >>>          systemctl stop rpc-statd.service >>>          systemctl stop nfs-server.service >>> >>>          systemctl restart rpcbind.service >>>          systemctl restart rpc-statd.service >>>          systemctl restart nfs-server.service >>> done >>> >>> When executing the script, you can observe that the >>> "cat /proc/net/unix | wc -l" count keeps growing. >>> >>> Add the missing fput(), and restore transport to old socket. >>> >>> Signed-off-by: Wang Hai >>> --- >>>   net/sunrpc/xprtsock.c | 20 ++++++++++++++++++-- >>>   1 file changed, 18 insertions(+), 2 deletions(-) >>> >>> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c >>> index 0f39e08ee580..7219c545385e 100644 >>> --- a/net/sunrpc/xprtsock.c >>> +++ b/net/sunrpc/xprtsock.c >>> @@ -1819,6 +1819,9 @@ static int xs_local_finish_connecting(struct >>> rpc_xprt *xprt, >>>   { >>>          struct sock_xprt *transport = container_of(xprt, struct >>> sock_xprt, >>>     xprt); >>> +       struct socket *trans_sock = NULL; >>> +       struct sock *trans_inet = NULL; >>> +       int ret; >>>            if (!transport->inet) { >>>                  struct sock *sk = sock->sk; >>> @@ -1835,6 +1838,9 @@ static int xs_local_finish_connecting(struct >>> rpc_xprt *xprt, >>>                    xprt_clear_connected(xprt); >>>   +               trans_sock = transport->sock; >>> +               trans_inet = transport->inet; >>> + >> Both values are NULL here > Got it, thanks >> >>>                  /* Reset to new socket */ >>>                  transport->sock = sock; >>>                  transport->inet = sk; >>> @@ -1844,7 +1850,14 @@ static int xs_local_finish_connecting(struct >>> rpc_xprt *xprt, >>>            xs_stream_start_connect(transport); >>>   -       return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0); >>> +       ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0); >>> +       /* Restore to old socket */ >>> +       if (ret && trans_inet) { >>> +               transport->sock = trans_sock; >>> +               transport->inet = trans_inet; >>> +       } >>> + >>> +       return ret; >>>   } >>>     /** >>> @@ -1887,7 +1900,7 @@ static int xs_local_setup_socket(struct >>> sock_xprt *transport) >>>                  xprt->stat.connect_time += (long)jiffies - >>> xprt->stat.connect_start; >>>                  xprt_set_connected(xprt); >>> -               break; >>> +               goto out; >>>          case -ENOBUFS: >>>                  break; >>>          case -ENOENT: >>> @@ -1904,6 +1917,9 @@ static int xs_local_setup_socket(struct >>> sock_xprt *transport) >>>                                  xprt- >>>> address_strings[RPC_DISPLAY_ADDR]); >>>          } >>>   +       transport->file = NULL; >>> +       fput(filp); >> Please just call xprt_force_disconnect() so that this can be cleaned up >> from     a safe context. > > Hi, Trond > > Thank you for your advice, I tried this, but it doesn't seem to > > work and an error is reported. I'll analyze why this happens > > Hi, Trond. If I call xprt_force_disconnect(), it reports the following error, I spent a long time but couldn't find the cause of the error. If I call xs_close(), it works, is it possible to call xs_close() here? [  107.147326][ T7128] ====================================================== [  107.147329][ T7128] WARNING: possible circular locking dependency detected [  107.147333][ T7128] 5.17.0+ #10 Not tainted [  107.147340][ T7128] ------------------------------------------------------ [  107.147343][ T7128] rpc.nfsd/7128 is trying to acquire lock: [  107.147349][ T7128] ffffffff850f4960 (console_owner){..-.}-{0:0}, at: console_unlock+0x1d7/0x790 [  107.147384][ T7128] [  107.147384][ T7128] but task is already holding lock: [  107.147387][ T7128] ffff88824010b418 (&pool->lock/1){-.-.}-{2:2}, at: __queue_work+0x450/0x810 [  107.147420][ T7128] [  107.147420][ T7128] which lock already depends on the new lock. [  107.147420][ T7128] [  107.147423][ T7128] [  107.147423][ T7128] the existing dependency chain (in reverse order) is: [  107.147426][ T7128] [  107.147426][ T7128] -> #2 (&pool->lock/1){-.-.}-{2:2}: [  107.147444][ T7128]        _raw_spin_lock+0x32/0x50 [  107.147482][ T7128]        __queue_work+0x131/0x810 [  107.147496][ T7128]        queue_work_on+0x88/0x90 [  107.147509][ T7128]        tty_flip_buffer_push+0x34/0x40 [  107.147525][ T7128]        serial8250_rx_chars+0x73/0x80 [  107.147537][ T7128] serial8250_handle_irq.part.21+0x124/0x160 [  107.147552][ T7128] serial8250_default_handle_irq+0x79/0x90 [  107.147566][ T7128]        serial8250_interrupt+0x73/0xd0 [  107.147581][ T7128]        __handle_irq_event_percpu+0x54/0x3c0 [  107.147597][ T7128]        handle_irq_event_percpu+0x1c/0x50 [  107.147611][ T7128]        handle_irq_event+0x3e/0x60 [  107.147624][ T7128]        handle_edge_irq+0xc3/0x250 [  107.147636][ T7128]        __common_interrupt+0x71/0x140 [  107.147649][ T7128]        common_interrupt+0xbc/0xe0 [  107.147664][ T7128]        asm_common_interrupt+0x1e/0x40 [  107.147677][ T7128]        default_idle+0x14/0x20 [  107.147687][ T7128]        arch_cpu_idle+0xf/0x20 [  107.147698][ T7128]        default_idle_call+0x6f/0x230 [  107.147709][ T7128]        do_idle+0x1c4/0x250 [  107.147722][ T7128]        cpu_startup_entry+0x1d/0x20 [  107.147736][ T7128]        start_secondary+0xe6/0xf0 [  107.147751][ T7128] secondary_startup_64_no_verify+0xc3/0xcb [  107.147767][ T7128] [  107.147767][ T7128] -> #1 (&port_lock_key){-.-.}-{2:2}: [  107.147783][ T7128]        _raw_spin_lock_irqsave+0x42/0x60 [  107.147795][ T7128]        serial8250_console_write+0x31b/0x380 [  107.147808][ T7128]        univ8250_console_write+0x3a/0x50 [  107.147820][ T7128]        console_unlock+0x51d/0x790 [  107.147832][ T7128]        vprintk_emit+0x252/0x320 [  107.147844][ T7128]        vprintk_default+0x2b/0x30 [  107.147856][ T7128]        vprintk+0x71/0x80 [  107.147868][ T7128]        _printk+0x63/0x82 [  107.147879][ T7128]        register_console+0x233/0x400 [  107.147892][ T7128]        univ8250_console_init+0x35/0x3f [  107.147907][ T7128]        console_init+0x233/0x345 [  107.147920][ T7128]        start_kernel+0xa70/0xbf8 [  107.147931][ T7128]        x86_64_start_reservations+0x2a/0x2c [  107.147947][ T7128]        x86_64_start_kernel+0x90/0x95 [  107.147961][ T7128] secondary_startup_64_no_verify+0xc3/0xcb [  107.147975][ T7128] [  107.147975][ T7128] -> #0 (console_owner){..-.}-{0:0}: [  107.147990][ T7128]        __lock_acquire+0x1552/0x1a30 [  107.148002][ T7128]        lock_acquire+0x25e/0x2f0 [  107.148014][ T7128]        console_unlock+0x22e/0x790 [  107.148026][ T7128]        vprintk_emit+0x252/0x320 [  107.148038][ T7128]        vprintk_default+0x2b/0x30 [  107.148050][ T7128]        vprintk+0x71/0x80 [  107.148061][ T7128]        _printk+0x63/0x82 [  107.148072][ T7128]        report_bug+0x1a6/0x1c0 [  107.148085][ T7128]        handle_bug+0x43/0x70 [  107.148098][ T7128]        exc_invalid_op+0x18/0x70 [  107.148111][ T7128]        asm_exc_invalid_op+0x12/0x20 [  107.148123][ T7128]        __queue_work+0x72a/0x810 [  107.148136][ T7128]        queue_work_on+0x88/0x90 [  107.148149][ T7128] xprt_schedule_autoclose_locked+0x7a/0xb0 [  107.148162][ T7128]        xprt_force_disconnect+0x53/0x150 [  107.148173][ T7128]        xs_local_setup_socket+0x2b2/0x480 [  107.148188][ T7128]        xs_setup_local+0x24b/0x280 [  107.148200][ T7128]        xprt_create_transport+0xb0/0x340 [  107.148212][ T7128]        rpc_create+0x104/0x2b0 [  107.148226][ T7128]        rpcb_create_local_unix+0xb2/0x2c0 [  107.148242][ T7128]        rpcb_create_local+0x79/0x90 [  107.148256][ T7128]        svc_bind+0x92/0xd0 [  107.148267][ T7128]        nfsd_create_serv+0x131/0x3a0 [  107.148280][ T7128]        write_ports+0x2d4/0x8d0 [  107.148292][ T7128]        nfsctl_transaction_write+0x70/0xb0 [  107.148305][ T7128]        vfs_write+0x11d/0x4b0 [  107.148319][ T7128]        ksys_write+0xe0/0x130 [  107.148330][ T7128]        __x64_sys_write+0x23/0x30 [  107.148343][ T7128]        do_syscall_64+0x34/0xb0 [  107.148356][ T7128] entry_SYSCALL_64_after_hwframe+0x44/0xae [  107.148369][ T7128] [  107.148369][ T7128] other info that might help us debug this: [  107.148369][ T7128] [  107.148372][ T7128] Chain exists of: [  107.148372][ T7128]   console_owner --> &port_lock_key --> &pool->lock/1 [  107.148372][ T7128] [  107.148392][ T7128]  Possible unsafe locking scenario: [  107.148392][ T7128] [  107.148395][ T7128]        CPU0                    CPU1 [  107.148397][ T7128]        ----                    ---- [  107.148399][ T7128]   lock(&pool->lock/1); [  107.148409][ T7128] lock(&port_lock_key); [  107.148416][ T7128] lock(&pool->lock/1); [  107.148426][ T7128]   lock(console_owner); [  107.148432][ T7128] [  107.148432][ T7128]  *** DEADLOCK *** [  107.148432][ T7128] [  107.148434][ T7128] 7 locks held by rpc.nfsd/7128: [  107.148442][ T7128]  #0: ffff8882480a4460 (sb_writers#12){.+.+}-{0:0}, at: ksys_write+0xe0/0x130 [  107.148474][ T7128]  #1: ffffffff8526ee88 (nfsd_mutex){+.+.}-{3:3}, at: write_ports+0x41/0x8d0 [  107.148503][ T7128]  #2: ffffffff854cdc88 (rpcb_create_local_mutex){+.+.}-{3:3}, at: rpcb_create_local+0x43/0x90 [  107.148534][ T7128]  #3: ffff888243f14740 (&xprt->transport_lock){+.+.}-{2:2}, at: xprt_force_disconnect+0x4b/0x150 [  107.148562][ T7128]  #4: ffffffff851d7a60 (rcu_read_lock){....}-{1:2}, at: __queue_work+0x5a/0x810 [  107.148592][ T7128]  #5: ffff88824010b418 (&pool->lock/1){-.-.}-{2:2}, at: __queue_work+0x450/0x810 [  107.148625][ T7128]  #6: ffffffff851d4d60 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0x114/0x320 [  107.148653][ T7128] [  107.148653][ T7128] stack backtrace: [  107.148656][ T7128] CPU: 3 PID: 7128 Comm: rpc.nfsd Not tainted 5.17.0+ #10 [  107.148670][ T7128] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [  107.148677][ T7128] Call Trace: [  107.148680][ T7128]  [  107.148685][ T7128]  dump_stack_lvl+0x6c/0x8b [  107.148702][ T7128]  dump_stack+0x15/0x17 [  107.148715][ T7128]  print_circular_bug.isra.46+0x261/0x2c0 [  107.148767][ T7128]  check_noncircular+0x105/0x120 [  107.148787][ T7128]  __lock_acquire+0x1552/0x1a30 [  107.148800][ T7128]  ? __lock_acquire+0x1552/0x1a30 [  107.148820][ T7128]  lock_acquire+0x25e/0x2f0 [  107.148833][ T7128]  ? console_unlock+0x1d7/0x790 [  107.148848][ T7128]  ? lock_release+0x204/0x2c0 [  107.148865][ T7128]  console_unlock+0x22e/0x790 [  107.148878][ T7128]  ? console_unlock+0x1d7/0x790 [  107.148900][ T7128]  vprintk_emit+0x252/0x320 [  107.148916][ T7128]  vprintk_default+0x2b/0x30 [  107.148931][ T7128]  vprintk+0x71/0x80 [  107.148945][ T7128]  _printk+0x63/0x82 [  107.148959][ T7128]  ? report_bug+0x19a/0x1c0 [  107.148974][ T7128]  ? __queue_work+0x72a/0x810 [  107.148988][ T7128]  report_bug+0x1a6/0x1c0 [  107.149004][ T7128]  handle_bug+0x43/0x70 [  107.149019][ T7128]  exc_invalid_op+0x18/0x70 [  107.149034][ T7128]  asm_exc_invalid_op+0x12/0x20 [  107.149047][ T7128] RIP: 0010:__queue_work+0x72a/0x810 [  107.149063][ T7128] Code: 48 c7 c7 78 7b b8 84 c6 05 b1 f4 39 04 01 e8 ad 65 05 00 e9 7f fe ff ff e8 33 94 11 00 4c 8b 33 e9 ff f9 ff ff e8 26 94 11 00 <0f> 0b e9 d2 fa ff ff e8 1a 94 11 00 4c 8d 7b 68 41 83 cc 02 e9 aa [  107.149077][ T7128] RSP: 0018:ffffc900042efa88 EFLAGS: 00010093 [  107.149087][ T7128] RAX: 0000000000000000 RBX: ffff88824013c100 RCX: 0000000000000000 [  107.149096][ T7128] RDX: ffff888111b15140 RSI: ffffffff8119be6a RDI: ffffffff84c6fd9e [  107.149104][ T7128] RBP: ffffc900042efac8 R08: 0000000000000001 R09: 0000000000000000 [  107.149112][ T7128] R10: 0000000000000002 R11: 000000000000f2ce R12: 0000000000000000 [  107.149120][ T7128] R13: ffff888243f14668 R14: ffff888237c2d440 R15: ffff888240ffc000 [  107.149134][ T7128]  ? __queue_work+0x72a/0x810 [  107.149151][ T7128]  ? __queue_work+0x72a/0x810 [  107.149169][ T7128]  queue_work_on+0x88/0x90 [  107.149185][ T7128]  xprt_schedule_autoclose_locked+0x7a/0xb0 [  107.149200][ T7128]  xprt_force_disconnect+0x53/0x150 [  107.149213][ T7128]  xs_local_setup_socket+0x2b2/0x480 [  107.149230][ T7128]  xs_setup_local+0x24b/0x280 [  107.149245][ T7128]  xprt_create_transport+0xb0/0x340 [  107.149259][ T7128]  rpc_create+0x104/0x2b0 [  107.149278][ T7128]  ? __this_cpu_preempt_check+0x1c/0x20 [  107.149293][ T7128]  ? lock_is_held_type+0xde/0x130 [  107.149307][ T7128]  rpcb_create_local_unix+0xb2/0x2c0 [  107.149332][ T7128]  rpcb_create_local+0x79/0x90 [  107.149348][ T7128]  svc_bind+0x92/0xd0 [  107.149363][ T7128]  nfsd_create_serv+0x131/0x3a0 [  107.149378][ T7128]  write_ports+0x2d4/0x8d0 [  107.149392][ T7128]  ? _copy_from_user+0x8b/0xe0 [  107.149411][ T7128]  ? nfsd_init_net+0x2d0/0x2d0 [  107.149425][ T7128]  nfsctl_transaction_write+0x70/0xb0 [  107.149439][ T7128]  ? export_features_show+0x30/0x30 [  107.149454][ T7128]  vfs_write+0x11d/0x4b0 [  107.149470][ T7128]  ksys_write+0xe0/0x130 [  107.149486][ T7128]  __x64_sys_write+0x23/0x30 [  107.149501][ T7128]  do_syscall_64+0x34/0xb0 [  107.149515][ T7128]  entry_SYSCALL_64_after_hwframe+0x44/0xae [  107.149530][ T7128] RIP: 0033:0x7feb99b00130 [  107.149540][ T7128] Code: 73 01 c3 48 8b 0d 58 ed 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 45 2d 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 3e f3 01 00 48 89 04 24 [  107.149553][ T7128] RSP: 002b:00007ffc849b68e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [  107.149565][ T7128] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007feb99b00130 [  107.149574][ T7128] RDX: 0000000000000002 RSI: 000055d532e09620 RDI: 0000000000000003 [  107.149581][ T7128] RBP: 0000000000000003 R08: 000055d532c06704 R09: 0000000000000000 [  107.149589][ T7128] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 [  107.149597][ T7128] R13: 000055d532e09620 R14: 000055d532c066bf R15: 000055d533474730 [  107.149614][ T7128]  [  107.283659][ T7128] WARNING: CPU: 3 PID: 7128 at kernel/workqueue.c:1499 __queue_work+0x72a/0x810 [  107.283659][ T7128] Modules linked in: [  107.283659][ T7128] CPU: 3 PID: 7128 Comm: rpc.nfsd Not tainted 5.17.0+ #10 [  107.283659][ T7128] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [  107.283659][ T7128] RIP: 0010:__queue_work+0x72a/0x810 [  107.283659][ T7128] Code: 48 c7 c7 78 7b b8 84 c6 05 b1 f4 39 04 01 e8 ad 65 05 00 e9 7f fe ff ff e8 33 94 11 00 4c 8b 33 e9 ff f9 ff ff e8 26 94 11 00 <0f> 0b e9 d2 fa ff ff e8 1a 94 11 00 4c 8d 7b 68 41 83 cc 02 e9 aa [  107.283659][ T7128] RSP: 0018:ffffc900042efa88 EFLAGS: 00010093 [  107.283659][ T7128] RAX: 0000000000000000 RBX: ffff88824013c100 RCX: 0000000000000000 [  107.283659][ T7128] RDX: ffff888111b15140 RSI: ffffffff8119be6a RDI: ffffffff84c6fd9e [  107.283659][ T7128] RBP: ffffc900042efac8 R08: 0000000000000001 R09: 0000000000000000 [  107.283659][ T7128] R10: 0000000000000002 R11: 000000000000f2ce R12: 0000000000000000 [  107.283659][ T7128] R13: ffff888243f14668 R14: ffff888237c2d440 R15: ffff888240ffc000 [  107.283659][ T7128] FS:  00007feb9a89ac80(0000) GS:ffff888437c80000(0000) knlGS:0000000000000000 [  107.283659][ T7128] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [  107.283659][ T7128] CR2: 00007ffc849ba084 CR3: 0000000247402000 CR4: 00000000000006e0 [  107.283659][ T7128] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [  107.283659][ T7128] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [  107.283659][ T7128] Call Trace: [  107.283659][ T7128]  [  107.283659][ T7128]  queue_work_on+0x88/0x90 [  107.283659][ T7128]  xprt_schedule_autoclose_locked+0x7a/0xb0 [  107.283659][ T7128]  xprt_force_disconnect+0x53/0x150 [  107.283659][ T7128]  xs_local_setup_socket+0x2b2/0x480 [  107.283659][ T7128]  xs_setup_local+0x24b/0x280 [  107.283659][ T7128]  xprt_create_transport+0xb0/0x340 [  107.283659][ T7128]  rpc_create+0x104/0x2b0 [  107.283659][ T7128]  ? __this_cpu_preempt_check+0x1c/0x20 [  107.283659][ T7128]  ? lock_is_held_type+0xde/0x130 [  107.283659][ T7128]  rpcb_create_local_unix+0xb2/0x2c0 [  107.283659][ T7128]  rpcb_create_local+0x79/0x90 [  107.283659][ T7128]  svc_bind+0x92/0xd0 [  107.283659][ T7128]  nfsd_create_serv+0x131/0x3a0 [  107.283659][ T7128]  write_ports+0x2d4/0x8d0 [  107.283659][ T7128]  ? _copy_from_user+0x8b/0xe0 [  107.283659][ T7128]  ? nfsd_init_net+0x2d0/0x2d0 [  107.283659][ T7128]  nfsctl_transaction_write+0x70/0xb0 [  107.283659][ T7128]  ? export_features_show+0x30/0x30 [  107.283659][ T7128]  vfs_write+0x11d/0x4b0 [  107.283659][ T7128]  ksys_write+0xe0/0x130 [  107.283659][ T7128]  __x64_sys_write+0x23/0x30 [  107.283659][ T7128]  do_syscall_64+0x34/0xb0 [  107.283659][ T7128]  entry_SYSCALL_64_after_hwframe+0x44/0xae [  107.283659][ T7128] RIP: 0033:0x7feb99b00130 [  107.283659][ T7128] Code: 73 01 c3 48 8b 0d 58 ed 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 45 2d 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 3e f3 01 00 48 89 04 24 [  107.283659][ T7128] RSP: 002b:00007ffc849b68e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [  107.283659][ T7128] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007feb99b00130 [  107.283659][ T7128] RDX: 0000000000000002 RSI: 000055d532e09620 RDI: 0000000000000003 [  107.283659][ T7128] RBP: 0000000000000003 R08: 000055d532c06704 R09: 0000000000000000 [  107.283659][ T7128] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 [  107.283659][ T7128] R13: 000055d532e09620 R14: 000055d532c066bf R15: 000055d533474730 [  107.283659][ T7128]  [  107.283659][ T7128] irq event stamp: 33702 [  107.283659][ T7128] hardirqs last  enabled at (33701): [] cmpxchg_double_slab.isra.52+0xe8/0x220 [  107.283659][ T7128] hardirqs last disabled at (33702): [] queue_work_on+0x73/0x90 [  107.283659][ T7128] softirqs last  enabled at (33670): [] unix_release_sock+0xfc/0x540 [  107.283659][ T7128] softirqs last disabled at (33668): [] unix_release_sock+0xd8/0x540 [  107.283659][ T7128] ---[ end trace 0000000000000000 ]--- [  107.622086][ T7128] svc: failed to register nfsdv2 RPC service (errno 111). [  107.627373][ T7128] svc: failed to register nfsaclv2 RPC service (errno 111). Job for nfs-server.service canceled. [  109.560632][ T7174] NFSD: Using UMH upcall client tracking operations. [  109.564229][ T7174] NFSD: starting 90-second grace period (net f0000000) >>> + >>>   out: >>>          xprt_clear_connecting(xprt); >>>          xprt_wake_pending_tasks(xprt, status); > -- Wang Hai