From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bernard f6bvp Subject: [NetRom] possible circular locking dependency detected Date: Sun, 21 Oct 2012 17:18:58 +0200 Message-ID: <50841262.4020704@free.fr> References: <4B2CD772.1030106@upmc.fr> <201106171536.15660.arnd@arndb.de> <20110617135147.GA3470@linux-mips.org> <201106171611.10655.arnd@arndb.de> <4E06040B.7040309@free.fr> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------020702000803080705030904" Return-path: In-Reply-To: <4E06040B.7040309@free.fr> Sender: linux-hams-owner@vger.kernel.org List-ID: To: Cc: Ralf Baechle , linux-kernel@vger.kernel.org, Linux Netdev List , linux-hams@vger.kernel.org, Bernard Pidoux This is a multi-part message in MIME format. --------------020702000803080705030904 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi, When shutting down my dual core system, there was a possible circular locking dependency detected that is related to NetRom. Here is the syslog report. Regards, Bernard, f6bvp --------------020702000803080705030904 Content-Type: text/plain; charset="windows-1252"; name="ax25ipd_not_tainted.txt" Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="ax25ipd_not_tainted.txt" Oct 21 12:10:35 f6bvp-8 aprslist[1773]: terminating on SIGTERM Oct 21 12:10:35 f6bvp-8 fpacstat: terminating on SIGTERM Oct 21 12:10:35 f6bvp-8 netromd[1653]: terminating on SIGTERM Oct 21 12:10:35 f6bvp-8 ax25ipd:=20 Oct 21 12:10:35 f6bvp-8 ax25ipd: socket udp on port 10094 Oct 21 12:10:35 f6bvp-8 ax25ipd: mode tnc Oct 21 12:10:35 f6bvp-8 ax25ipd: device /dev/ptmx Oct 21 12:10:35 f6bvp-8 ax25ipd: speed 115200 Oct 21 12:10:35 f6bvp-8 ax25ipd: loglevel 1 Oct 21 12:10:35 f6bvp-8 ax25ipd:=20 Oct 21 12:10:35 f6bvp-8 ax25ipd: K4GBB 184.4.148.122 udp 10094 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: F8COJ 0.0.0.0 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: F3KT 62.147.189.164 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: F6BVP-12 192.168.0.68 udp 10093 4 Oct 21 12:10:35 f6bvp-8 ax25ipd: F6BVP-11 192.168.0.115 udp 10093 4 Oct 21 12:10:35 f6bvp-8 ax25ipd: F6BVP-10 192.168.0.115 udp 10093 5 Oct 21 12:10:35 f6bvp-8 ax25ipd: VA2BBS 24.212.252.110 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: ON4HU 81.243.88.115 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: IZ3LSV 88.149.155.158 udp 10094 5 Oct 21 12:10:35 f6bvp-8 ax25ipd:=20 Oct 21 12:10:35 f6bvp-8 nfs-server[27474]: Arr=C3=AAt de NFS kernel daemon Oct 21 12:10:36 f6bvp-8 kernel: [522519.150299]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150313] =3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Oct 21 12:10:36 f6bvp-8 kernel: [522519.150317] [ INFO: possible circular l= ocking dependency detected ] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150321] 3.6.1 #1 Not tainted Oct 21 12:10:36 f6bvp-8 kernel: [522519.150325] ---------------------------= ---------------------------- Oct 21 12:10:36 f6bvp-8 kernel: [522519.150329] ax25ipd/1580 is trying to a= cquire lock: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150333] (nr_node_list_lock){+.....= }, at: [] nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150352]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150352] but task is already holding= lock: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150356] (nr_neigh_list_lock){+.-.-= .}, at: [] nr_rt_device_down+0x26/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150373]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150373] which lock already depends = on the new lock. Oct 21 12:10:36 f6bvp-8 kernel: [522519.150373]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150378]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150378] the existing dependency cha= in (in reverse order) is: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150382]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150382] -> #2 (nr_neigh_list_lock){= +.-.-.}: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150396] []= lock_acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150409] []= _raw_spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150418] []= nr_remove_neigh+0x1b/0xb0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150429] []= nr_rt_ioctl+0x2b0/0xa60 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150438] []= nr_ioctl+0x51/0x1d0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150445] []= sock_do_ioctl+0x30/0x70 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150454] []= sock_ioctl+0x79/0x2f0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150460] []= do_vfs_ioctl+0x98/0x560 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150468] []= sys_ioctl+0x91/0xa0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150477] []= system_call_fastpath+0x16/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.150486]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150486] -> #1 (&(&nr_node->node_loc= k)->rlock){+.....}: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150498] []= lock_acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150505] []= _raw_spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150512] []= nr_node_show+0x4c/0x150 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150522] []= seq_read+0x26c/0x420 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150529] []= proc_reg_read+0x86/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150537] []= vfs_read+0xac/0x180 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150546] []= sys_read+0x4a/0x90 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150552] []= system_call_fastpath+0x16/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.150559]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150559] -> #0 (nr_node_list_lock){+= .....}: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150571] []= __lock_acquire+0x1a91/0x1ce0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150578] []= lock_acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150586] []= _raw_spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150592] []= nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150601] []= nr_device_event+0x7d/0xa0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150608] []= notifier_call_chain+0x58/0xb0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150617] []= raw_notifier_call_chain+0x16/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150625] []= call_netdevice_notifiers+0x36/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150633] []= dev_close_many+0xbf/0x100 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150639] []= rollback_registered_many+0xd8/0x250 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150645] []= rollback_registered+0x2d/0x40 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150653] []= unregister_netdevice_queue+0x68/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150659] []= unregister_netdev+0x20/0x30 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150666] []= mkiss_close+0x57/0x90 [mkiss] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150674] []= tty_ldisc_close.isra.2+0x41/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150683] []= tty_ldisc_reinit+0x40/0x80 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150689] []= tty_ldisc_hangup+0x190/0x340 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150695] []= __tty_hangup+0x10a/0x3c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150703] []= tty_vhangup+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150709] []= pty_close+0x10e/0x180 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150716] []= tty_release+0x182/0x5c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150724] []= __fput+0xae/0x230 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150734] []= ____fput+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150740] []= task_work_run+0x69/0x90 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150748] []= do_exit+0x87f/0x900 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150756] []= do_group_exit+0x4e/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150763] []= sys_exit_group+0x17/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150770] []= system_call_fastpath+0x16/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.150778]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150778] other info that might help = us debug this: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150778]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150782] Chain exists of: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150782] nr_node_list_lock --> &(&= nr_node->node_lock)->rlock --> nr_neigh_list_lock Oct 21 12:10:36 f6bvp-8 kernel: [522519.150782]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150799] Possible unsafe locking sc= enario: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150799]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150803] CPU0 = CPU1 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150806] ---- = ---- Oct 21 12:10:36 f6bvp-8 kernel: [522519.150809] lock(nr_neigh_list_lock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150819] = lock(&(&nr_node->node_lock)->rlock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150826] = lock(nr_neigh_list_lock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150834] lock(nr_node_list_lock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150842]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150842] *** DEADLOCK *** Oct 21 12:10:36 f6bvp-8 kernel: [522519.150842]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150847] 4 locks held by ax25ipd/158= 0: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150851] #0: (big_tty_mutex){+.+.+= .}, at: [] tty_lock+0x17/0x19 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150867] #1: (&tty->ldisc_mutex){+= .+.+.}, at: [] tty_ldisc_hangup+0x117/0x340 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150885] #2: (rtnl_mutex){+.+.+.},= at: [] rtnl_lock+0x17/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150901] #3: (nr_neigh_list_lock){= +.-.-.}, at: [] nr_rt_device_down+0x26/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150921]=20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150921] stack backtrace: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150927] Pid: 1580, comm: ax25ipd No= t tainted 3.6.1 #1 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150930] Call Trace: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150938] [] print= _circular_bug+0x289/0x29a Oct 21 12:10:36 f6bvp-8 kernel: [522519.150945] [] __loc= k_acquire+0x1a91/0x1ce0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150954] [] ? nr_= rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150960] [] lock_= acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150969] [] ? nr_= rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150976] [] _raw_= spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150984] [] ? nr_= rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150990] [] ? tra= ce_hardirqs_on_caller+0x105/0x190 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150997] [] ? nr_= device_event+0x71/0xa0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151005] [] nr_rt= _device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151011] [] ? loc= al_bh_enable_ip+0x97/0x100 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151019] [] nr_de= vice_event+0x7d/0xa0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151026] [] notif= ier_call_chain+0x58/0xb0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151033] [] raw_n= otifier_call_chain+0x16/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151038] [] call_= netdevice_notifiers+0x36/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151044] [] dev_c= lose_many+0xbf/0x100 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151050] [] rollb= ack_registered_many+0xd8/0x250 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151055] [] rollb= ack_registered+0x2d/0x40 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151061] [] unreg= ister_netdevice_queue+0x68/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151068] [] unreg= ister_netdev+0x20/0x30 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151077] [] mkiss= _close+0x57/0x90 [mkiss] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151083] [] tty_l= disc_close.isra.2+0x41/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151089] [] tty_l= disc_reinit+0x40/0x80 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151094] [] tty_l= disc_hangup+0x190/0x340 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151101] [] __tty= _hangup+0x10a/0x3c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151107] [] ? tra= ce_hardirqs_on+0xd/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151114] [] tty_v= hangup+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151120] [] pty_c= lose+0x10e/0x180 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151126] [] tty_r= elease+0x182/0x5c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151132] [] ? dpu= t+0x62/0x1b0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151138] [] __fpu= t+0xae/0x230 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151144] [] ____f= put+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] task_= work_run+0x69/0x90 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] do_ex= it+0x87f/0x900 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] ? ret= int_swapgs+0x13/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] do_gr= oup_exit+0x4e/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] sys_e= xit_group+0x17/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] syste= m_call_fastpath+0x16/0x1b --------------020702000803080705030904-- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932177Ab2JUPTG (ORCPT ); Sun, 21 Oct 2012 11:19:06 -0400 Received: from smtp3-g21.free.fr ([212.27.42.3]:38313 "EHLO smtp3-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753737Ab2JUPTD (ORCPT ); Sun, 21 Oct 2012 11:19:03 -0400 Message-ID: <50841262.4020704@free.fr> Date: Sun, 21 Oct 2012 17:18:58 +0200 From: Bernard f6bvp User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 CC: Ralf Baechle , linux-kernel@vger.kernel.org, Linux Netdev List , linux-hams@vger.kernel.org, Bernard Pidoux Subject: [NetRom] possible circular locking dependency detected References: <4B2CD772.1030106@upmc.fr> <201106171536.15660.arnd@arndb.de> <20110617135147.GA3470@linux-mips.org> <201106171611.10655.arnd@arndb.de> <4E06040B.7040309@free.fr> In-Reply-To: <4E06040B.7040309@free.fr> Content-Type: multipart/mixed; boundary="------------020702000803080705030904" To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------020702000803080705030904 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi, When shutting down my dual core system, there was a possible circular locking dependency detected that is related to NetRom. Here is the syslog report. Regards, Bernard, f6bvp --------------020702000803080705030904 Content-Type: text/plain; charset=windows-1252; name="ax25ipd_not_tainted.txt" Content-Transfer-Encoding: 8bit Content-Disposition: attachment; filename="ax25ipd_not_tainted.txt" Oct 21 12:10:35 f6bvp-8 aprslist[1773]: terminating on SIGTERM Oct 21 12:10:35 f6bvp-8 fpacstat: terminating on SIGTERM Oct 21 12:10:35 f6bvp-8 netromd[1653]: terminating on SIGTERM Oct 21 12:10:35 f6bvp-8 ax25ipd: Oct 21 12:10:35 f6bvp-8 ax25ipd: socket udp on port 10094 Oct 21 12:10:35 f6bvp-8 ax25ipd: mode tnc Oct 21 12:10:35 f6bvp-8 ax25ipd: device /dev/ptmx Oct 21 12:10:35 f6bvp-8 ax25ipd: speed 115200 Oct 21 12:10:35 f6bvp-8 ax25ipd: loglevel 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: Oct 21 12:10:35 f6bvp-8 ax25ipd: K4GBB 184.4.148.122 udp 10094 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: F8COJ 0.0.0.0 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: F3KT 62.147.189.164 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: F6BVP-12 192.168.0.68 udp 10093 4 Oct 21 12:10:35 f6bvp-8 ax25ipd: F6BVP-11 192.168.0.115 udp 10093 4 Oct 21 12:10:35 f6bvp-8 ax25ipd: F6BVP-10 192.168.0.115 udp 10093 5 Oct 21 12:10:35 f6bvp-8 ax25ipd: VA2BBS 24.212.252.110 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: ON4HU 81.243.88.115 udp 10093 1 Oct 21 12:10:35 f6bvp-8 ax25ipd: IZ3LSV 88.149.155.158 udp 10094 5 Oct 21 12:10:35 f6bvp-8 ax25ipd: Oct 21 12:10:35 f6bvp-8 nfs-server[27474]: Arrêt de NFS kernel daemon Oct 21 12:10:36 f6bvp-8 kernel: [522519.150299] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150313] ====================================================== Oct 21 12:10:36 f6bvp-8 kernel: [522519.150317] [ INFO: possible circular locking dependency detected ] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150321] 3.6.1 #1 Not tainted Oct 21 12:10:36 f6bvp-8 kernel: [522519.150325] ------------------------------------------------------- Oct 21 12:10:36 f6bvp-8 kernel: [522519.150329] ax25ipd/1580 is trying to acquire lock: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150333] (nr_node_list_lock){+.....}, at: [] nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150352] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150352] but task is already holding lock: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150356] (nr_neigh_list_lock){+.-.-.}, at: [] nr_rt_device_down+0x26/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150373] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150373] which lock already depends on the new lock. Oct 21 12:10:36 f6bvp-8 kernel: [522519.150373] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150378] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150378] the existing dependency chain (in reverse order) is: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150382] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150382] -> #2 (nr_neigh_list_lock){+.-.-.}: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150396] [] lock_acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150409] [] _raw_spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150418] [] nr_remove_neigh+0x1b/0xb0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150429] [] nr_rt_ioctl+0x2b0/0xa60 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150438] [] nr_ioctl+0x51/0x1d0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150445] [] sock_do_ioctl+0x30/0x70 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150454] [] sock_ioctl+0x79/0x2f0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150460] [] do_vfs_ioctl+0x98/0x560 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150468] [] sys_ioctl+0x91/0xa0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150477] [] system_call_fastpath+0x16/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.150486] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150486] -> #1 (&(&nr_node->node_lock)->rlock){+.....}: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150498] [] lock_acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150505] [] _raw_spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150512] [] nr_node_show+0x4c/0x150 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150522] [] seq_read+0x26c/0x420 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150529] [] proc_reg_read+0x86/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150537] [] vfs_read+0xac/0x180 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150546] [] sys_read+0x4a/0x90 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150552] [] system_call_fastpath+0x16/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.150559] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150559] -> #0 (nr_node_list_lock){+.....}: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150571] [] __lock_acquire+0x1a91/0x1ce0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150578] [] lock_acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150586] [] _raw_spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150592] [] nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150601] [] nr_device_event+0x7d/0xa0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150608] [] notifier_call_chain+0x58/0xb0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150617] [] raw_notifier_call_chain+0x16/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150625] [] call_netdevice_notifiers+0x36/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150633] [] dev_close_many+0xbf/0x100 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150639] [] rollback_registered_many+0xd8/0x250 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150645] [] rollback_registered+0x2d/0x40 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150653] [] unregister_netdevice_queue+0x68/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150659] [] unregister_netdev+0x20/0x30 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150666] [] mkiss_close+0x57/0x90 [mkiss] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150674] [] tty_ldisc_close.isra.2+0x41/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150683] [] tty_ldisc_reinit+0x40/0x80 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150689] [] tty_ldisc_hangup+0x190/0x340 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150695] [] __tty_hangup+0x10a/0x3c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150703] [] tty_vhangup+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150709] [] pty_close+0x10e/0x180 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150716] [] tty_release+0x182/0x5c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150724] [] __fput+0xae/0x230 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150734] [] ____fput+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150740] [] task_work_run+0x69/0x90 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150748] [] do_exit+0x87f/0x900 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150756] [] do_group_exit+0x4e/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150763] [] sys_exit_group+0x17/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150770] [] system_call_fastpath+0x16/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.150778] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150778] other info that might help us debug this: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150778] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150782] Chain exists of: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150782] nr_node_list_lock --> &(&nr_node->node_lock)->rlock --> nr_neigh_list_lock Oct 21 12:10:36 f6bvp-8 kernel: [522519.150782] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150799] Possible unsafe locking scenario: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150799] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150803] CPU0 CPU1 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150806] ---- ---- Oct 21 12:10:36 f6bvp-8 kernel: [522519.150809] lock(nr_neigh_list_lock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150819] lock(&(&nr_node->node_lock)->rlock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150826] lock(nr_neigh_list_lock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150834] lock(nr_node_list_lock); Oct 21 12:10:36 f6bvp-8 kernel: [522519.150842] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150842] *** DEADLOCK *** Oct 21 12:10:36 f6bvp-8 kernel: [522519.150842] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150847] 4 locks held by ax25ipd/1580: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150851] #0: (big_tty_mutex){+.+.+.}, at: [] tty_lock+0x17/0x19 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150867] #1: (&tty->ldisc_mutex){+.+.+.}, at: [] tty_ldisc_hangup+0x117/0x340 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150885] #2: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150901] #3: (nr_neigh_list_lock){+.-.-.}, at: [] nr_rt_device_down+0x26/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150921] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150921] stack backtrace: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150927] Pid: 1580, comm: ax25ipd Not tainted 3.6.1 #1 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150930] Call Trace: Oct 21 12:10:36 f6bvp-8 kernel: [522519.150938] [] print_circular_bug+0x289/0x29a Oct 21 12:10:36 f6bvp-8 kernel: [522519.150945] [] __lock_acquire+0x1a91/0x1ce0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150954] [] ? nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150960] [] lock_acquire+0x92/0x120 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150969] [] ? nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150976] [] _raw_spin_lock_bh+0x36/0x50 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150984] [] ? nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.150990] [] ? trace_hardirqs_on_caller+0x105/0x190 Oct 21 12:10:36 f6bvp-8 kernel: [522519.150997] [] ? nr_device_event+0x71/0xa0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151005] [] nr_rt_device_down+0x7c/0x240 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151011] [] ? local_bh_enable_ip+0x97/0x100 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151019] [] nr_device_event+0x7d/0xa0 [netrom] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151026] [] notifier_call_chain+0x58/0xb0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151033] [] raw_notifier_call_chain+0x16/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151038] [] call_netdevice_notifiers+0x36/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151044] [] dev_close_many+0xbf/0x100 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151050] [] rollback_registered_many+0xd8/0x250 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151055] [] rollback_registered+0x2d/0x40 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151061] [] unregister_netdevice_queue+0x68/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151068] [] unregister_netdev+0x20/0x30 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151077] [] mkiss_close+0x57/0x90 [mkiss] Oct 21 12:10:36 f6bvp-8 kernel: [522519.151083] [] tty_ldisc_close.isra.2+0x41/0x60 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151089] [] tty_ldisc_reinit+0x40/0x80 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151094] [] tty_ldisc_hangup+0x190/0x340 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151101] [] __tty_hangup+0x10a/0x3c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151107] [] ? trace_hardirqs_on+0xd/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151114] [] tty_vhangup+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151120] [] pty_close+0x10e/0x180 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151126] [] tty_release+0x182/0x5c0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151132] [] ? dput+0x62/0x1b0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151138] [] __fput+0xae/0x230 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151144] [] ____fput+0xe/0x10 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] task_work_run+0x69/0x90 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] do_exit+0x87f/0x900 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] ? retint_swapgs+0x13/0x1b Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] do_group_exit+0x4e/0xc0 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] sys_exit_group+0x17/0x20 Oct 21 12:10:36 f6bvp-8 kernel: [522519.151148] [] system_call_fastpath+0x16/0x1b --------------020702000803080705030904--