Re: RCU stalls -> lockup.

From: Paul E. McKenney
Date: Thu Oct 02 2014 - 15:37:08 EST

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In reply to: Dave Jones: "RCU stalls -> lockup."
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On Thu, Oct 02, 2014 at 01:55:15PM -0400, Dave Jones wrote:
> I just hit this on my box running 3.17rc7
> It was followed by a userspace lockup. (Could still ping, and sysrq
> from the console, but even getty wasn't responding on the console).
>
> I was trying to reproduce another bug faster, and had ramped up the
> number of processes trinity to uses to 512. This didn't take long
> to fall out..

This might be related to an exchange I had with Tejun (CCed), where
the work queues were running all out, preventing any quiescent states
from happening. One fix under consideration is to add a quiescent state,
similar to the one in softirq handling.

Thanx, Paul

> INFO: rcu_preempt detected stalls on CPUs/tasks:
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> (detected by 3, t=6502 jiffies, g=1014253, c=1014252, q=0)
> INFO: Stall ended before state dump start
> INFO: rcu_preempt detected stalls on CPUs/tasks:
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> (detected by 0, t=26007 jiffies, g=1014253, c=1014252, q=0)
> INFO: Stall ended before state dump start
> INFO: rcu_preempt detected stalls on CPUs/tasks:
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> (detected by 2, t=45512 jiffies, g=1014253, c=1014252, q=0)
> INFO: Stall ended before state dump start
> INFO: rcu_preempt detected stalls on CPUs/tasks:
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> Tasks blocked on level-0 rcu_node (CPUs 0-3):
> (detected by 1, t=65017 jiffies, g=1014253, c=1014252, q=0)
> INFO: Stall ended before state dump start
> INFO: rcu_preempt detected stalls on CPUs/tasks:
> Tasks blocked on level-0 rcu_node (CPUs 0-3): P15547 P15232 P15616 P15634
> Tasks blocked on level-0 rcu_node (CPUs 0-3): P15547 P15232 P15616 P15634
> (detected by 1, t=6502 jiffies, g=1014254, c=1014253, q=0)
> trinity-c318 R running task 13480 15547 14371 0x00000000
> ffff880031df7df0 0000000000000002 ffffffff870cb70e ffff88008ec30000
> 00000000001d4080 0000000000000000 ffff880031df7fd8 00000000001d4080
> ffff8802166c2de0 ffff88008ec30000 ffff880031df7fd8 ffffffff872361f4
> Call Trace:
> [<ffffffff870cb70e>] ? put_lock_stats.isra.28+0xe/0x30
> [<ffffffff872361f4>] ? bdi_queue_work+0xe4/0x1a0
> [<ffffffff8781df46>] preempt_schedule+0x36/0x60
> [<ffffffff8700e3d6>] ___preempt_schedule+0x56/0xb0
> [<ffffffff872361f4>] ? bdi_queue_work+0xe4/0x1a0
> [<ffffffff8707db77>] ? __local_bh_enable_ip+0xb7/0xe0
> [<ffffffff87823a45>] _raw_spin_unlock_bh+0x35/0x40
> [<ffffffff872361f4>] bdi_queue_work+0xe4/0x1a0
> [<ffffffff87236318>] __bdi_start_writeback+0x68/0x190
> [<ffffffff87238eb0>] wakeup_flusher_threads+0x100/0x1e0
> [<ffffffff87238de0>] ? wakeup_flusher_threads+0x30/0x1e0
> [<ffffffff8723cd86>] sys_sync+0x36/0xb0
> [<ffffffff878249e4>] tracesys+0xdd/0xe2
> trinity-c9 R running task 13496 15232 14371 0x00000000
> ffff88011a01fdf0 0000000000000002 ffffffff870cb70e ffff8800a19616f0
> 00000000001d4080 0000000000000000 ffff88011a01ffd8 00000000001d4080
> ffff8802166c2de0 ffff8800a19616f0 ffff88011a01ffd8 ffffffff872361f4
> Call Trace:
> [<ffffffff870cb70e>] ? put_lock_stats.isra.28+0xe/0x30
> [<ffffffff872361f4>] ? bdi_queue_work+0xe4/0x1a0
> [<ffffffff8781df46>] preempt_schedule+0x36/0x60
> [<ffffffff8700e3d6>] ___preempt_schedule+0x56/0xb0
> [<ffffffff872361f4>] ? bdi_queue_work+0xe4/0x1a0
> [<ffffffff8707db77>] ? __local_bh_enable_ip+0xb7/0xe0
> [<ffffffff87823a45>] _raw_spin_unlock_bh+0x35/0x40
> [<ffffffff872361f4>] bdi_queue_work+0xe4/0x1a0
> [<ffffffff87236318>] __bdi_start_writeback+0x68/0x190
> [<ffffffff87238eb0>] wakeup_flusher_threads+0x100/0x1e0
> [<ffffffff87238de0>] ? wakeup_flusher_threads+0x30/0x1e0
> [<ffffffff8723cd86>] sys_sync+0x36/0xb0
> [<ffffffff878249e4>] tracesys+0xdd/0xe2
> trinity-c387 R running task 13272 15616 14371 0x00000004
> ffff880043fd37f8 0000000000000002 ffff880001fd3868 ffff88023304ade0
> 00000000001d4080 0000000000000000 ffff880043fd3fd8 00000000001d4080
> ffff8802166c2de0 ffff88023304ade0 ffff880043fd3fd8 0000000000000000
> Call Trace:
> [<ffffffff8781e182>] preempt_schedule_irq+0x52/0xb0
> [<ffffffff87825550>] retint_kernel+0x20/0x30
> [<ffffffff87190624>] ? find_get_entry+0xb4/0x270
> [<ffffffff8719076e>] ? find_get_entry+0x1fe/0x270
> [<ffffffff87190575>] ? find_get_entry+0x5/0x270
> [<ffffffff871907ff>] find_lock_entry+0x1f/0x90
> [<ffffffff871acb65>] shmem_getpage_gfp+0xd5/0xa10
> [<ffffffff871adb3d>] shmem_fault+0x6d/0x1c0
> [<ffffffff871bff58>] __do_fault+0x48/0xd0
> [<ffffffff871c25e0>] do_shared_fault.isra.75+0x40/0x1c0
> [<ffffffff8718892b>] ? __perf_sw_event+0x4b/0x380
> [<ffffffff871c3b21>] handle_mm_fault+0x261/0xcd0
> [<ffffffff870cb687>] ? __lock_is_held+0x57/0x80
> [<ffffffff87042c84>] __do_page_fault+0x1a4/0x600
> [<ffffffff870cbbf6>] ? lock_release_holdtime.part.29+0xe6/0x160
> [<ffffffff8718eda7>] ? context_tracking_user_exit+0x67/0x1b0
> [<ffffffff870430fe>] do_page_fault+0x1e/0x70
> [<ffffffff878264b2>] page_fault+0x22/0x30
> [<ffffffff871bd7e3>] ? copy_page_to_iter+0x3b3/0x500
> [<ffffffff871bd5fe>] ? copy_page_to_iter+0x1ce/0x500
> [<ffffffff8723a2b0>] ? vmsplice_to_user+0x130/0x130
> [<ffffffff8723a2d2>] pipe_to_user+0x22/0x40
> [<ffffffff87239d4e>] __splice_from_pipe+0x11e/0x190
> [<ffffffff8723a254>] vmsplice_to_user+0xd4/0x130
> [<ffffffff870cb101>] ? trace_hardirqs_off_caller+0x21/0xc0
> [<ffffffff878253e4>] ? retint_restore_args+0xe/0xe
> [<ffffffff870ac74d>] ? get_parent_ip+0xd/0x50
> [<ffffffff870ac8ab>] ? preempt_count_sub+0x6b/0xf0
> [<13480 15547 14371 0x00000000
> ffff880031df7df0 0000000000000002 ffffffff870cb70e ffff88008ec30000
> 00000000001d4080 0000000000000000 ffff880031df7fd8 00000000001d4080
> ffff8801039344d0 ffff88008ec30000 ffff880031df7fd8 ffffffff872361f4
> Call Trace:
> [<ffffffff870cb70e>] ? put_lock_stats.isra.28+0xe/0x30
> [<ffffffff872361f4>] ? bdi_queue_work+0xe4/0x1a0
> [<ffffffff8781df46>] preempt_schedule+0x36/0x60
> [<ffffffff8700e3d6>] ___preempt_schedule+0x56/0xb0
> [<ffffffff872361f4>] ? bdi_queue_work+0xe4/0x1a0
> [<ffffffff8707db77>] ? __local_bh_enable_ip+0xb7/0xe0
> [<ffffffff87823a45>] _raw_spin_unlock_bh+0x35/0x40
> [<ffffffff872361f4>] bdi_queue_work+0xe4/0x1a0
> [<ffffffff87236318>] __bdi_start_writeback+0x68/0x190
> [<ffffffff87238eb0>] wakeup_flusher_threads+0x100/0x1e0
> [<ffffffff87238de0>] ? wakeup_flusher_threads+0x30/0x1e0
> [<ffffffff8723cd86>] sys_sync+0x36/0xb0
> [<ffffffff878249e4>] tracesys+0xdd/0xe2
> trinity-c9 R running task 13496 15232 14371 0x00000000
> ffff88011a01fe58 0000000000000002 ffffffff87238ecf ffff8800a19616f0
> 00000000001d4080 0000000000000000 ffff88011a01ffd8 00000000001d4080
> ffff880085d35bc0 ffff8800a19616f0 ffff88011a01ffd8 0000000000000000
> Call Trace:
> [<ffffffff87238ecf>] ? wakeup_flusher_threads+0x11f/0x1e0
> [<ffffffff87238ecf>] ? wakeup_flusher_threads+0x11f/0x1e0
> [<ffffffff8781e182>] preempt_schedule_irq+0x52/0xb0
> [<ffffffff87825550>] retint_kernel+0x20/0x30
> [<ffffffff87238ecf>] ? wakeup_flusher_threads+0x11f/0x1e0
> [<ffffffff870d1049>] ? lock_release+0x29/0x300
> [<ffffffff87238ee7>] wakeup_flusher_threads+0x137/0x1e0
> [<ffffffff87238de0>] ? wakeup_flusher_threads+0x30/0x1e0
> [<ffffffff8723cd86>] sys_sync+0x36/0xb0
> [<ffffffff878249e4>] tracesys+0xdd/0xe2
> trinity-c387 R running task 13272 15616 14371 0x00000004
> ffff880043fd37f8 0000000000000002 ffff880001fd3868 ffff88023304ade0
> 00000000001d4080 0000000000000000 ffff880043fd3fd8 00000000001d4080
> ffff8801039344d0 ffff88023304ade0 ffff880043fd3fd8 0000000000000000
> Call Trace:
> [<ffffffff8781e182>] preempt_schedule_irq+0x52/0xb0
> [<ffffffff87825550>] retint_kernel+0x20/0x30
> [<ffffffff87190624>] ? find_get_entry+0xb4/0x270
> [<ffffffff8719076e>] ? find_get_entry+0x1fe/0x270
> [<ffffffff87190575>] ? find_get_entry+0x5/0x270
> [<ffffffff871907ff>] find_lock_entry+0x1f/0x90
> [<ffffffff871acb65>] shmem_getpage_gfp+0xd5/0xa10
> [<ffffffff871adb3d>] shmem_fault+0x6d/0x1c0
> [<ffffffff871bff58>] __do_fault+0x48/0xd0
> [<ffffffff871c25e0>] do_shared_fault.isra.75+0x40/0x1c0
> [<ffffffff8718892b>] ? __perf_sw_event+0x4b/0x380
> [<ffffffff871c3b21>] handle_mm_fault+0x261/0xcd0
> [<ffffffff870cb687>] ? __lock_is_held+0x57/0x80
> [<ffffffff87042c84>] __do_page_fault+0x1a4/0x600
> [<ffffffff870cbbf6>] ? lock_release_holdtime.part.29+0xe6/0x160
> [<ffffffff8718eda7>] ? context_tracking_user_exit+0x67/0x1b0
> [<ffffffff870430fe>] do_page_fault+0x1e/0x70
> [<ffffffff878264b2>] page_fault+0x22/0x30
> [<ffffffff871bd7e3>] ? copy_page_to_iter+0x3b3/0x500
> [<ffffffff871bd5fe>] ? copy_page_to_iter+0x1ce/0x500
> [<ffffffff8723a2b0>] ? vmsplice_to_user+0x130/0x130
> [<ffffffff8723a2d2>] pipe_to_user+0x22/0x40
> [<ffffffff87239d4e>] __splice_from_pipe+0x11e/0x190
> [<ffffffff8723a254>] vmsplice_to_user+0xd4/0x130
> [<ffffffff870cb101>] ? trace_hardirqs_off_caller+0x21/0xc0
> [<ffffffff878253e4>] ? retint_restore_args+0xe/0xe
> [<ffffffff870ac74d>] ? get_parent_ip+0xd/0x50
> [<ffffffff870ac8ab>] ? preempt_count_sub+0x6b/0xf0
> [<ffffffff8723bd31>] SyS_vmsplice+0xc1/0xe0
>

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Next message: Frans Klaver: "Re: [PATCH] [TRIVIAL] mod_devicetable.h: grammar fix in comment"
Previous message: Michael Opdenacker: "Re: [PATCH] [TRIVIAL] mod_devicetable.h: grammar fix in comment"
In reply to: Dave Jones: "RCU stalls -> lockup."
Next in thread: Tejun Heo: "Re: RCU stalls -> lockup."
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]