From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Boyer Subject: Re: localed stuck in recent 3.18 git in copy_net_ns? Date: Wed, 22 Oct 2014 13:12:25 -0400 Message-ID: References: <20141020141515.0688bf33@voldemort.scrye.com> <20141020204326.GA25668@redhat.com> <20141020145359.565fe5e6@voldemort.scrye.com> <20141021151225.5df96645@voldemort.scrye.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: netdev , "Linux-Kernel@Vger. Kernel. Org" To: Kevin Fenzi Return-path: In-Reply-To: <20141021151225.5df96645@voldemort.scrye.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Oct 21, 2014 at 5:12 PM, Kevin Fenzi wrote: > On Mon, 20 Oct 2014 14:53:59 -0600 > Kevin Fenzi wrote: > >> On Mon, 20 Oct 2014 16:43:26 -0400 >> Dave Jones wrote: >> >> > I've seen similar soft lockup traces from the sys_unshare path when >> > running my fuzz tester. It seems that if you create enough network >> > namespaces, it can take a huge amount of time for them to be >> > iterated. (Running trinity with '-c unshare' you can see the slow >> > down happen. In some cases, it takes so long that the watchdog >> > process kills it -- though the SIGKILL won't get delivered until >> > the unshare() completes) >> > >> > Any idea what this machine had been doing prior to this that may >> > have involved creating lots of namespaces ? >> >> That was right after boot. ;) >> >> This is my main rawhide running laptop. >> >> A 'ip netns list' shows nothing. > > Some more information: > > The problem started between: > > v3.17-7872-g5ff0b9e1a1da and v3.17-8307-gf1d0d14120a8 > > (I can try and do a bisect, but have to head out on a trip tomorrow) > > In all the kernels with the problem, there is a kworker process in D. > > sysrq-t says: > Showing all locks held in the system: > Oct 21 15:06:31 voldemort.scrye.com kernel: 4 locks held by kworker/u16:0/6: > Oct 21 15:06:31 voldemort.scrye.com kernel: #0: ("%s""netns"){.+.+.+}, at: [] process_one_work+0x17f/0x850 > Oct 21 15:06:31 voldemort.scrye.com kernel: #1: (net_cleanup_work){+.+.+.}, at: [] process_one_work+0x17f/0x850 > Oct 21 15:06:31 voldemort.scrye.com kernel: #2: (net_mutex){+.+.+.}, at: [] cleanup_net+0x8c/0x1f0 > Oct 21 15:06:31 voldemort.scrye.com kernel: #3: > (rcu_sched_state.barrier_mutex){+.+...}, at: [] > _rcu_barrier+0x35/0x200 > > On first running any of the systemd units that use PrivateNetwork, then > run ok, but they are also set to timeout after a minute. On sucessive > runs they hang in D also. Someone else is seeing this when they try and modprobe ppp_generic: [ 240.599195] INFO: task kworker/u16:5:100 blocked for more than 120 seconds. [ 240.599338] Not tainted 3.18.0-0.rc1.git2.1.fc22.x86_64 #1 [ 240.599446] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 240.599583] kworker/u16:5 D ffff8802202db480 12400 100 2 0x00000000 [ 240.599744] Workqueue: netns cleanup_net [ 240.599823] ffff8802202eb9e8 0000000000000096 ffff8802202db480 00000000001d5f00 [ 240.600066] ffff8802202ebfd8 00000000001d5f00 ffff8800368c3480 ffff8802202db480 [ 240.600228] ffffffff81ee2690 7fffffffffffffff ffffffff81ee2698 ffffffff81ee2690 [ 240.600386] Call Trace: [ 240.600445] [] schedule+0x29/0x70 [ 240.600541] [] schedule_timeout+0x26c/0x410 [ 240.600651] [] ? retint_restore_args+0x13/0x13 [ 240.600765] [] ? _raw_spin_unlock_irq+0x34/0x50 [ 240.600879] [] wait_for_completion+0x10c/0x150 [ 240.601025] [] ? wake_up_state+0x20/0x20 [ 240.601133] [] _rcu_barrier+0x159/0x200 [ 240.601237] [] rcu_barrier+0x15/0x20 [ 240.601335] [] netdev_run_todo+0x6f/0x310 [ 240.601442] [] ? rollback_registered_many+0x265/0x2e0 [ 240.601564] [] rtnl_unlock+0xe/0x10 [ 240.601660] [] default_device_exit_batch+0x156/0x180 [ 240.601781] [] ? abort_exclusive_wait+0xb0/0xb0 [ 240.601895] [] ops_exit_list.isra.1+0x53/0x60 [ 240.602028] [] cleanup_net+0x100/0x1f0 [ 240.602131] [] process_one_work+0x218/0x850 [ 240.602241] [] ? process_one_work+0x17f/0x850 [ 240.602350] [] ? worker_thread+0xe7/0x4a0 [ 240.602454] [] worker_thread+0x6b/0x4a0 [ 240.602555] [] ? process_one_work+0x850/0x850 [ 240.602665] [] kthread+0x10b/0x130 [ 240.602762] [] ? sched_clock+0x9/0x10 [ 240.602862] [] ? kthread_create_on_node+0x250/0x250 [ 240.603004] [] ret_from_fork+0x7c/0xb0 [ 240.603106] [] ? kthread_create_on_node+0x250/0x250 [ 240.603224] 4 locks held by kworker/u16:5/100: [ 240.603304] #0: ("%s""netns"){.+.+.+}, at: [] process_one_work+0x17f/0x850 [ 240.603495] #1: (net_cleanup_work){+.+.+.}, at: [] process_one_work+0x17f/0x850 [ 240.603691] #2: (net_mutex){+.+.+.}, at: [] cleanup_net+0x8c/0x1f0 [ 240.603869] #3: (rcu_sched_state.barrier_mutex){+.+...}, at: [] _rcu_barrier+0x35/0x200 [ 240.604211] INFO: task modprobe:1387 blocked for more than 120 seconds. [ 240.604329] Not tainted 3.18.0-0.rc1.git2.1.fc22.x86_64 #1 [ 240.604434] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 240.604570] modprobe D ffff8800cb4f1a40 13112 1387 1386 0x00000080 [ 240.604719] ffff8800cafbbbe8 0000000000000096 ffff8800cb4f1a40 00000000001d5f00 [ 240.604878] ffff8800cafbbfd8 00000000001d5f00 ffff880223280000 ffff8800cb4f1a40 [ 240.605068] ffff8800cb4f1a40 ffffffff81f8fb48 0000000000000246 ffff8800cb4f1a40 [ 240.605228] Call Trace: [ 240.605283] [] schedule_preempt_disabled+0x31/0x80 [ 240.605400] [] mutex_lock_nested+0x183/0x440 [ 240.605510] [] ? register_pernet_subsys+0x1f/0x50 [ 240.605626] [] ? register_pernet_subsys+0x1f/0x50 [ 240.605757] [] ? 0xffffffffa0701000 [ 240.605854] [] register_pernet_subsys+0x1f/0x50 [ 240.606005] [] br_init+0x48/0xd3 [bridge] [ 240.606112] [] do_one_initcall+0xd8/0x210 [ 240.606224] [] load_module+0x20c2/0x2870 [ 240.606327] [] ? store_uevent+0x70/0x70 [ 240.606433] [] ? lock_release_non_nested+0x3c6/0x3d0 [ 240.606557] [] SyS_init_module+0xe7/0x140 [ 240.606664] [] system_call_fastpath+0x12/0x17 [ 240.606773] 1 lock held by modprobe/1387: [ 240.606845] #0: (net_mutex){+.+.+.}, at: [] register_pernet_subsys+0x1f/0x50 [ 240.607114] INFO: task modprobe:1466 blocked for more than 120 seconds. [ 240.607231] Not tainted 3.18.0-0.rc1.git2.1.fc22.x86_64 #1 [ 240.607337] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 240.607473] modprobe D ffff88020fbab480 13096 1466 1399 0x00000084 [ 240.607622] ffff88020d1bbbe8 0000000000000096 ffff88020fbab480 00000000001d5f00 [ 240.607791] ffff88020d1bbfd8 00000000001d5f00 ffffffff81e1b580 ffff88020fbab480 [ 240.607949] ffff88020fbab480 ffffffff81f8fb48 0000000000000246 ffff88020fbab480 [ 240.608138] Call Trace: [ 240.608193] [] schedule_preempt_disabled+0x31/0x80 [ 240.608316] [] mutex_lock_nested+0x183/0x440 [ 240.608425] [] ? register_pernet_device+0x1d/0x70 [ 240.608542] [] ? register_pernet_device+0x1d/0x70 [ 240.608662] [] ? 0xffffffffa071d000 [ 240.608759] [] register_pernet_device+0x1d/0x70 [ 240.608881] [] ppp_init+0x20/0x1000 [ppp_generic] [ 240.609021] [] do_one_initcall+0xd8/0x210 [ 240.609131] [] load_module+0x20c2/0x2870 [ 240.609235] [] ? store_uevent+0x70/0x70 [ 240.609339] [] ? lock_release_non_nested+0x3c6/0x3d0 [ 240.609462] [] SyS_init_module+0xe7/0x140 [ 240.609568] [] system_call_fastpath+0x12/0x17 [ 240.609677] 1 lock held by modprobe/1466: [ 240.609749] #0: (net_mutex){+.+.+.}, at: [] register_pernet_device+0x1d/0x70 Looks like contention on net_mutex or something, but I honestly have no idea yet. I can't recreate it myself at the moment or I would bisect. Has nobody else run into this with the pre-3.18 kernels? Fedora isn't carrying any patches in this area. josh