Re: [Xen-devel] rcu_sched self-detected stall on CPU on kernel 4.4.5/6 in PV DomU

[Steven Haigh <netwiz@xxxxxxxxx>]

Just wanted to give a bit of a poke about this.

Currently running kernel 4.4.6 in a PV DomU and still occasionally 
getting hangs.
Also stumbled across this that may be related:
    https://lkml.org/lkml/2016/2/4/724

My latest hang shows:
[339844.594001] INFO: rcu_sched self-detected stall on CPU
[339844.594001]         1-...: (287557828 ticks this GP) 
idle=4cb/140000000000001/0 softirq=1340383/1340384 fqs=95372371
[339844.594001]          (t=287566692 jiffies g=999283 c=999282 
q=1725381)
[339844.594001] Task dump for CPU 1:
[339844.594001] find            R  running task        0  2840   2834 
0x00000088
[339844.594001]  ffffffff818d0c00 ffff88007fd03c58 ffffffff810a625f 
0000000000000001
[339844.594001]  ffffffff818d0c00 ffff88007fd03c70 ffffffff810a8699 
0000000000000002
[339844.594001]  ffff88007fd03ca0 ffffffff810d0e5a ffff88007fd170c0 
ffffffff818d0c00
[339844.594001] Call Trace:
[339844.594001]  <IRQ>  [<ffffffff810a625f>] sched_show_task+0xaf/0x110
[339844.594001]  [<ffffffff810a8699>] dump_cpu_task+0x39/0x40
[339844.594001]  [<ffffffff810d0e5a>] rcu_dump_cpu_stacks+0x8a/0xc0
[339844.594001]  [<ffffffff810d4884>] rcu_check_callbacks+0x424/0x7a0
[339844.594001]  [<ffffffff810a91e1>] ? account_system_time+0x81/0x110
[339844.594001]  [<ffffffff810a9481>] ? account_process_tick+0x61/0x160
[339844.594001]  [<ffffffff810e8050>] ? tick_sched_do_timer+0x30/0x30
[339844.594001]  [<ffffffff810d9749>] update_process_times+0x39/0x60
[339844.594001]  [<ffffffff810e7aa6>] 
tick_sched_handle.isra.15+0x36/0x50
[339844.594001]  [<ffffffff810e808d>] tick_sched_timer+0x3d/0x70
[339844.594001]  [<ffffffff810da342>] __hrtimer_run_queues+0xf2/0x250
[339844.594001]  [<ffffffff810da698>] hrtimer_interrupt+0xa8/0x190
[339844.594001]  [<ffffffff8100c61e>] xen_timer_interrupt+0x2e/0x140
[339844.594001]  [<ffffffff810c8555>] handle_irq_event_percpu+0x55/0x1e0
[339844.594001]  [<ffffffff810cbbca>] handle_percpu_irq+0x3a/0x50
[339844.594001]  [<ffffffff810c7d22>] generic_handle_irq+0x22/0x30
[339844.594001]  [<ffffffff813e50ff>] 
__evtchn_fifo_handle_events+0x15f/0x180
[339844.594001]  [<ffffffff813e5130>] 
evtchn_fifo_handle_events+0x10/0x20
[339844.594001]  [<ffffffff813e2233>] __xen_evtchn_do_upcall+0x43/0x80
[339844.594001]  [<ffffffff813e3ea0>] xen_evtchn_do_upcall+0x30/0x50
[339844.594001]  [<ffffffff8165deb2>] xen_hvm_callback_vector+0x82/0x90
[339844.594001]  <EOI>  [<ffffffff8165bc60>] ? _raw_spin_lock+0x10/0x3


On 2016-03-19 08:46, Steven Haigh wrote:
> On 19/03/2016 8:40 AM, Steven Haigh wrote:
> > Hi all,
> >
> > So I'd just like to give this a prod. I'm still getting DomU's 
> > randomly
> > go to 100% CPU usage using kernel 4.4.6 now. It seems running 4.4.6 as
> > the DomU does not induce these problems.
> Sorry - slight correction. Running 4.4.6 as the Dom0 kernel doesn't 
> show
> these errors. Only in the DomU.
>
> > Latest crash message from today:
> > INFO: rcu_sched self-detected stall on CPU
> >         0-...: (20869552 ticks this GP) idle=9c9/140000000000001/0
> > softirq=1440865/1440865 fqs=15068
> >          (t=20874993 jiffies g=1354899 c=1354898 q=798)
> > rcu_sched kthread starved for 20829030 jiffies! g1354899 c1354898 f0x0
> > s3 ->state=0x0
> > Task dump for CPU 0:
> > kworker/u4:1    R  running task        0  5853      2 0x00000088
> > Workqueue: writeback wb_workfn (flush-202:0)
> >  ffffffff818d0c00 ffff88007fc03c58 ffffffff810a625f 0000000000000000
> >  ffffffff818d0c00 ffff88007fc03c70 ffffffff810a8699 0000000000000001
> >  ffff88007fc03ca0 ffffffff810d0e5a ffff88007fc170c0 ffffffff818d0c00
> > Call Trace:
> >  <IRQ>  [<ffffffff810a625f>] sched_show_task+0xaf/0x110
> >  [<ffffffff810a8699>] dump_cpu_task+0x39/0x40
> >  [<ffffffff810d0e5a>] rcu_dump_cpu_stacks+0x8a/0xc0
> >  [<ffffffff810d4884>] rcu_check_callbacks+0x424/0x7a0
> >  [<ffffffff810a91e1>] ? account_system_time+0x81/0x110
> >  [<ffffffff810a9481>] ? account_process_tick+0x61/0x160
> >  [<ffffffff810e8050>] ? tick_sched_do_timer+0x30/0x30
> >  [<ffffffff810d9749>] update_process_times+0x39/0x60
> >  [<ffffffff810e7aa6>] tick_sched_handle.isra.15+0x36/0x50
> >  [<ffffffff810e808d>] tick_sched_timer+0x3d/0x70
> >  [<ffffffff810da342>] __hrtimer_run_queues+0xf2/0x250
> >  [<ffffffff810da698>] hrtimer_interrupt+0xa8/0x190
> >  [<ffffffff8100c61e>] xen_timer_interrupt+0x2e/0x140
> >  [<ffffffff810c8555>] handle_irq_event_percpu+0x55/0x1e0
> >  [<ffffffff810cbbca>] handle_percpu_irq+0x3a/0x50
> >  [<ffffffff810c7d22>] generic_handle_irq+0x22/0x30
> >  [<ffffffff813e50ff>] __evtchn_fifo_handle_events+0x15f/0x180
> >  [<ffffffff813e5130>] evtchn_fifo_handle_events+0x10/0x20
> >  [<ffffffff813e2233>] __xen_evtchn_do_upcall+0x43/0x80
> >  [<ffffffff813e3ea0>] xen_evtchn_do_upcall+0x30/0x50
> >  [<ffffffff8165deb2>] xen_hvm_callback_vector+0x82/0x90
> >  <EOI>  [<ffffffff810b9ce2>] ? queued_spin_lock_slowpath+0x22/0x170
> >  [<ffffffff8165bc70>] _raw_spin_lock+0x20/0x30
> >  [<ffffffff811f1f34>] writeback_sb_inodes+0x124/0x560
> >  [<ffffffff8165ba36>] ? _raw_spin_unlock_irqrestore+0x16/0x20
> >  [<ffffffff811f23f6>] __writeback_inodes_wb+0x86/0xc0
> >  [<ffffffff811f2606>] wb_writeback+0x1d6/0x2d0
> >  [<ffffffff811f2e94>] wb_workfn+0x284/0x3e0
> >  [<ffffffff81093831>] process_one_work+0x151/0x400
> >  [<ffffffff8109437a>] worker_thread+0x11a/0x460
> >  [<ffffffff8165848f>] ? __schedule+0x2bf/0x880
> >  [<ffffffff81094260>] ? rescuer_thread+0x2f0/0x2f0
> >  [<ffffffff810993d9>] kthread+0xc9/0xe0
> >  [<ffffffff81099310>] ? kthread_park+0x60/0x60
> >  [<ffffffff8165c38f>] ret_from_fork+0x3f/0x70
> >  [<ffffffff81099310>] ? kthread_park+0x60/0x60
> >
> > This repeats over and over causing 100% CPU usage - eventually on all
> > vcpus assigned to the DomU and the only recovery is 'xl destroy'.
> >
> > I'm currently running Xen 4.6.1 on this system - with kernel 4.4.6 in
> > both the DomU and Dom0.
> >
> > On 17/03/2016 8:39 AM, Steven Haigh wrote:
> > > Hi all,
> > >
> > > I've noticed the following problem that ends up with a non-repsonsive 
> > > PV
> > > DomU using kernel 4.4.5 under heavy disk IO:
> > >
> > > INFO: rcu_sched self-detected stall on CPU
> > >         0-...: (6759098 ticks this GP) idle=cb3/140000000000001/0
> > > softirq=3244615/3244615 fqs=4
> > >          (t=6762321 jiffies g=2275626 c=2275625 q=54)
> > > rcu_sched kthread starved for 6762309 jiffies! g2275626 c2275625 f0x0 
> > > s3
> > > ->state=0x0
> > > Task dump for CPU 0:
> > > updatedb        R  running task        0  6027   6021 0x00000088
> > >  ffffffff818d0c00 ffff88007fc03c58 ffffffff810a625f 0000000000000000
> > >  ffffffff818d0c00 ffff88007fc03c70 ffffffff810a8699 0000000000000001
> > >  ffff88007fc03ca0 ffffffff810d0e5a ffff88007fc170c0 ffffffff818d0c00
> > > Call Trace:
> > >  <IRQ>  [<ffffffff810a625f>] sched_show_task+0xaf/0x110
> > >  [<ffffffff810a8699>] dump_cpu_task+0x39/0x40
> > >  [<ffffffff810d0e5a>] rcu_dump_cpu_stacks+0x8a/0xc0
> > >  [<ffffffff810d4884>] rcu_check_callbacks+0x424/0x7a0
> > >  [<ffffffff810a91e1>] ? account_system_time+0x81/0x110
> > >  [<ffffffff810a9481>] ? account_process_tick+0x61/0x160
> > >  [<ffffffff810e8050>] ? tick_sched_do_timer+0x30/0x30
> > >  [<ffffffff810d9749>] update_process_times+0x39/0x60
> > >  [<ffffffff810e7aa6>] tick_sched_handle.isra.15+0x36/0x50
> > >  [<ffffffff810e808d>] tick_sched_timer+0x3d/0x70
> > >  [<ffffffff810da342>] __hrtimer_run_queues+0xf2/0x250
> > >  [<ffffffff810da698>] hrtimer_interrupt+0xa8/0x190
> > >  [<ffffffff8100c61e>] xen_timer_interrupt+0x2e/0x140
> > >  [<ffffffff810c8555>] handle_irq_event_percpu+0x55/0x1e0
> > >  [<ffffffff810cbbca>] handle_percpu_irq+0x3a/0x50
> > >  [<ffffffff810c7d22>] generic_handle_irq+0x22/0x30
> > >  [<ffffffff813e51af>] __evtchn_fifo_handle_events+0x15f/0x180
> > >  [<ffffffff813e51e0>] evtchn_fifo_handle_events+0x10/0x20
> > >  [<ffffffff813e22e3>] __xen_evtchn_do_upcall+0x43/0x80
> > >  [<ffffffff813e3f50>] xen_evtchn_do_upcall+0x30/0x50
> > >  [<ffffffff8165def2>] xen_hvm_callback_vector+0x82/0x90
> > >  <EOI>  [<ffffffff810b9cd0>] ? queued_spin_lock_slowpath+0x10/0x170
> > >  [<ffffffff8165bcc0>] _raw_spin_lock+0x20/0x30
> > >  [<ffffffff811df221>] find_inode_fast+0x61/0xa0
> > >  [<ffffffff811df7ce>] iget_locked+0x6e/0x170
> > >  [<ffffffff81249203>] ext4_iget+0x33/0xae0
> > >  [<ffffffff81658f02>] ? out_of_line_wait_on_bit+0x72/0x80
> > >  [<ffffffff81249ce0>] ext4_iget_normal+0x30/0x40
> > >  [<ffffffff81253415>] ext4_lookup+0xd5/0x140
> > >  [<ffffffff811ceffd>] lookup_real+0x1d/0x50
> > >  [<ffffffff811cf3b3>] __lookup_hash+0x33/0x40
> > >  [<ffffffff811d1af7>] walk_component+0x177/0x280
> > >  [<ffffffff811d2c50>] path_lookupat+0x60/0x110
> > >  [<ffffffff811d47dc>] filename_lookup+0x9c/0x150
> > >  [<ffffffff811a982d>] ? kfree+0x10d/0x290
> > >  [<ffffffff8124122c>] ? call_filldir+0x9c/0x130
> > >  [<ffffffff811d441f>] ? getname_flags+0x4f/0x1f0
> > >  [<ffffffff811d4946>] user_path_at_empty+0x36/0x40
> > >  [<ffffffff811ca6f3>] vfs_fstatat+0x53/0xa0
> > >  [<ffffffff811c7919>] ? __fput+0x169/0x1d0
> > >  [<ffffffff811cab42>] SYSC_newlstat+0x22/0x40
> > >  [<ffffffff8110cad0>] ? __audit_syscall_exit+0x1f0/0x270
> > >  [<ffffffff81078115>] ? syscall_slow_exit_work+0x3f/0xc0
> > >  [<ffffffff8110c88f>] ? __audit_syscall_entry+0xaf/0x100
> > >  [<ffffffff811cad4e>] SyS_newlstat+0xe/0x10
> > >  [<ffffffff8165c06e>] entry_SYSCALL_64_fastpath+0x12/0x71
> > >
> > > This ends up with the system not responding at 100% CPU usage.
> > >
> > > Has anyone else seen this using kernel 4.4.5 in a DomU?
--
Steven Haigh

Email: netwiz@xxxxxxxxx
Web: https://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897

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