From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751157Ab3FWFCs (ORCPT ); Sun, 23 Jun 2013 01:02:48 -0400 Received: from relay.parallels.com ([195.214.232.42]:43450 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750825Ab3FWFCr (ORCPT ); Sun, 23 Jun 2013 01:02:47 -0400 Date: Sun, 23 Jun 2013 09:00:24 +0400 From: Andrew Vagin To: Dave Jones , Oleg Nesterov , "Paul E. McKenney" , Linux Kernel , Linus Torvalds , "Eric W. Biederman" , Andrey Vagin Subject: Re: frequent softlockups with 3.10rc6. Message-ID: <20130623050023.GA678@paralelels.com> References: <20130619164540.GB22483@redhat.com> <20130619175356.GA23673@redhat.com> <20130619181302.GE5146@linux.vnet.ibm.com> <20130620001212.GB12151@redhat.com> <20130620161652.GA4462@linux.vnet.ibm.com> <20130621151119.GA1596@redhat.com> <20130621195949.GA15519@redhat.com> <20130622013731.GA22918@redhat.com> <20130622173129.GA29375@redhat.com> <20130622215905.GA28238@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="koi8-r" Content-Disposition: inline In-Reply-To: <20130622215905.GA28238@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Originating-IP: [10.24.21.206] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 22, 2013 at 05:59:05PM -0400, Dave Jones wrote: > On Sat, Jun 22, 2013 at 07:31:29PM +0200, Oleg Nesterov wrote: > > > > [ 7485.261299] WARNING: at include/linux/nsproxy.h:63 get_proc_task_net+0x1c8/0x1d0() > > > [ 7485.262021] Modules linked in: 8021q garp stp tun fuse rfcomm bnep hidp snd_seq_dummy nfnetlink scsi_transport_iscsi can_bcm ipt_ULOG can_raw rds af_802154 nfc can rose caif_socket caif llc2 af_rxrpc phonet ipx p8023 p8022 pppoe pppox ppp_generic netrom slhc ax25 x25 af_key appletalk atm psnap llc irda crc_ccitt bluetooth rfkill coretemp hwmon kvm_intel snd_hda_codec_realtek kvm snd_hda_codec_hdmi crc32c_intel ghash_clmulni_intel microcode snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device pcspkr snd_pcm snd_page_alloc e1000e snd_timer ptp snd pps_core soundcore xfs libcrc32c > > > [ 7485.265434] CPU: 2 PID: 5623 Comm: trinity-child3 Not tainted 3.10.0-rc6+ #28 > > > [ 7485.267158] ffffffff81a1529c ffff8801c8eafd30 ffffffff816e432d ffff8801c8eafd68 > > > [ 7485.268045] ffffffff8104a0c1 0000000000000000 ffff880225e9bd18 ffff8801bc6e4de0 > > > [ 7485.268932] 0000000000000000 00000000000000dd ffff8801c8eafd78 ffffffff8104a19a > > > [ 7485.270463] Call Trace: > > > [ 7485.271338] [] dump_stack+0x19/0x1b > > > [ 7485.272207] [] warn_slowpath_common+0x61/0x80 > > > [ 7485.273092] [] warn_slowpath_null+0x1a/0x20 > > > [ 7485.273942] [] get_proc_task_net+0x1c8/0x1d0 > > > [ 7485.274793] [] ? get_proc_task_net+0x5/0x1d0 > > > [ 7485.275659] [] proc_tgid_net_lookup+0x1d/0x80 > > > [ 7485.276531] [] lookup_real+0x1d/0x50 > > > [ 7485.277646] [] __lookup_hash+0x33/0x40 > > > [ 7485.278477] [] kern_path_create+0xb3/0x190 > > > [ 7485.279345] [] ? getname_flags+0xb5/0x190 > > > [ 7485.280292] [] user_path_create+0x41/0x60 > > > [ 7485.281233] [] SyS_symlinkat+0x4b/0xd0 > > > [ 7485.282072] [] tracesys+0xdd/0xe2 > > > [ 7485.282973] ---[ end trace 2204b7c65d6c5519 ]--- > > > > Hmm. The test case tries to create the symlink in /proc/*/net/ ? > > hit it with symlink, but also some other syscalls. eg: > > WARNING: at include/linux/nsproxy.h:63 get_proc_task_net+0x1c8/0x1d0() > Modules linked in: 8021q garp stp tun fuse rfcomm bnep hidp snd_seq_dummy nfnetlink scsi_transport_iscsi can_bcm ipt_ULOG can_raw rds af_802154 nfc can rose caif_socket caif llc2 af_rxrpc phonet ipx p8023 p8022 pppoe pppox ppp_generic netrom slhc ax25 x25 af_key appletalk atm psnap llc irda crc_ccitt bluetooth rfkill coretemp hwmon kvm_intel snd_hda_codec_realtek kvm snd_hda_codec_hdmi crc32c_intel ghash_clmulni_intel microcode snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device pcspkr snd_pcm snd_page_alloc e1000e snd_timer ptp snd pps_core soundcore xfs libcrc32c > CPU: 2 PID: 12821 Comm: trinity-child2 Tainted: G W 3.10.0-rc6+ #28 > ffffffff81a1529c ffff8801bcbdbc70 ffffffff816e432d ffff8801bcbdbca8 > ffffffff8104a0c1 0000000000000000 ffff880226704828 ffff8801b95a7090 > 00000000ffffff9c 0000000000000008 ffff8801bcbdbcb8 ffffffff8104a19a > Call Trace: > [] dump_stack+0x19/0x1b > [] warn_slowpath_common+0x61/0x80 > [] warn_slowpath_null+0x1a/0x20 > [] get_proc_task_net+0x1c8/0x1d0 > [] ? get_proc_task_net+0x5/0x1d0 > [] proc_tgid_net_lookup+0x1d/0x80 > [] lookup_real+0x1d/0x50 > [] __lookup_hash+0x33/0x40 > [] lookup_slow+0x44/0xa9 > [] path_lookupat+0x7b8/0x810 > [] ? kmem_cache_alloc+0x142/0x320 > [] ? getname_flags+0x4f/0x190 > [] ? getname_flags+0x4f/0x190 > [] filename_lookup+0x2b/0xc0 > [] user_path_at_empty+0x54/0x90 > [] ? user_exit+0x45/0x90 > [] ? trace_hardirqs_on_caller+0xfd/0x1c0 > [] user_path_at+0x11/0x20 > [] SyS_lgetxattr+0x38/0x90 > [] tracesys+0xdd/0xe2 > ---[ end trace 2204b7c65d6c551a ]--- > > > and a bunch of other similar VFS related calls. All these VFS related calls try to work with /proc/PID/ns/SMTH. If a process is zombie, it's detached from namespaces (except pidns), so if we try to read /proc/PID/ns/SMTH, we get this warning. >