Re: mm: hung task (handle_pte_fault)

[Avi Kivity]

On 03/23/2012 12:45 PM, Sasha Levin wrote:
> Hi guys,
>
> During fuzzing using trinity inside a KVM tools guest with latest
> linux-next, I seem to be getting it hung once in a while, with the
> following spew:
>
> [ 1441.420617] INFO: task trinity:2706 blocked for more than 120 seconds.
> [ 1441.421894] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> disables this message.
> [ 1441.424493] trinity         D 0000000000000000  3472  2706  16846 0x00000004
> [ 1441.426749]  ffff880029dbbb38 0000000000000086 ffff880029dbbae8
> ffff880029dbbfd8
> [ 1441.428582]  00000000001d45c0 ffff880029dba000 00000000001d45c0
> 00000000001d45c0
> [ 1441.430156]  00000000001d45c0 00000000001d45c0 ffff880029dbbfd8
> 00000000001d45c0
> [ 1441.432371] Call Trace:
> [ 1441.433042]  [<ffffffff81176dd0>] ? file_read_actor+0x1d0/0x1d0
> [ 1441.434251]  [<ffffffff827148d4>] schedule+0x24/0x70
> [ 1441.435314]  [<ffffffff82714e67>] io_schedule+0x87/0xd0
> [ 1441.436357]  [<ffffffff81176dd9>] sleep_on_page+0x9/0x10
> [ 1441.437442]  [<ffffffff82712cb7>] __wait_on_bit+0x57/0x80
> [ 1441.438584]  [<ffffffff81177bff>] ? __lock_page_or_retry+0x8f/0xd0
> [ 1441.439948]  [<ffffffff811775de>] wait_on_page_bit+0x6e/0x80
> [ 1441.440859]  [<ffffffff810d6d20>] ? autoremove_wake_function+0x40/0x40
> [ 1441.441700]  [<ffffffff810dbfbe>] ? up_read+0x1e/0x40
> [ 1441.442428]  [<ffffffff81177c36>] __lock_page_or_retry+0xc6/0xd0
> [ 1441.443270]  [<ffffffff81178490>] filemap_fault+0x440/0x4e0
> [ 1441.444072]  [<ffffffff811991cf>] __do_fault+0x7f/0x5f0
> [ 1441.444829]  [<ffffffff81112c00>] ?
> add_lock_to_list.clone.18.clone.27+0xd0/0xe0
> [ 1441.445886]  [<ffffffff8119cd27>] handle_pte_fault+0xf7/0x1e0
> [ 1441.446740]  [<ffffffff8119e1ce>] handle_mm_fault+0x1ce/0x330
> [ 1441.447537]  [<ffffffff8119e53c>] __get_user_pages+0x14c/0x640
> [ 1441.448399]  [<ffffffff811129ae>] ? put_lock_stats.clone.19+0xe/0x40
> [ 1441.449288]  [<ffffffff81117b1d>] ? __lock_acquired+0x19d/0x270
> [ 1441.450164]  [<ffffffff811a0087>] __mlock_vma_pages_range+0x87/0xa0
> [ 1441.451127]  [<ffffffff811a0129>] do_mlock_pages+0x89/0x160
> [ 1441.451932]  [<ffffffff811a0b71>] sys_mlockall+0x111/0x1a0
> [ 1441.452761]  [<ffffffff827176bd>] system_call_fastpath+0x1a/0x1f
> [ 1441.453659] no locks held by trinity/2706.
> [ 1441.454267] Kernel panic - not syncing: hung_task: blocked tasks
>
> According to the logs, it's not the direct result of anything specific
> happening, so I can't give an exact scenario to reproduce it. It does
> happen rather often.
>

Ingo notes that this could well be a kvm problem.  Does your processor
support EPT/NPT?  Can you provide kvm_stat and traces of what's
happening in the host when this triggers?

-- 
error compiling committee.c: too many arguments to function

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