Re: [LKP] [lkp] [net] 9317bb6982: INFO: task cat-kmsg:893 blocked for more than 300 seconds.

[Eric Dumazet]

Oh right, sorry for the delay.

On Thu, May 12, 2016 at 8:01 PM, Huang, Ying <ying.huang@xxxxxxxxx> wrote:
> "Huang, Ying" <ying.huang@xxxxxxxxx> writes:
>
>> Eric Dumazet <edumazet@xxxxxxxxxx> writes:
>>> On Mon, May 9, 2016 at 6:26 PM, Huang, Ying <ying.huang@xxxxxxxxxxxxxxx> wrote:
>>>> Hi, Eric,
>>>>
>>>> kernel test robot <ying.huang@xxxxxxxxxxxxxxx> writes:
>>>>> FYI, we noticed the following commit:
>>>>>
>>>>> git://internal_merge_and_test_tree devel-catchup-201604281529
>>>>> commit 9317bb69824ec8d078b0b786b6971aedb0af3d4f ("net: SOCKWQ_ASYNC_NOSPACE optimizations")
>>>>>
>>>>> on test machine: vm-kbuild-2G: 2 threads qemu-system-x86_64 -enable-kvm -cpu Haswell,+smep,+smap with 2G memory
>>>>>
>>>>> caused below changes:
>>>>>
>>>>>
>>>>> +--------------------------------------------------+------------+------------+
>>>>> |                                                  | 210732d16d | 9317bb6982 |
>>>>> +--------------------------------------------------+------------+------------+
>>>>> | boot_successes                                   | 40         | 13         |
>>>>> | boot_failures                                    | 0          | 27         |
>>>>> | INFO:task_blocked_for_more_than#seconds          | 0          | 27         |
>>>>> | RIP:native_safe_halt                             | 0          | 20         |
>>>>> | RIP:native_write_msr_safe                        | 0          | 27         |
>>>>> | Kernel_panic-not_syncing:hung_task:blocked_tasks | 0          | 27         |
>>>>> | backtrace:__close_fd                             | 0          | 27         |
>>>>> | backtrace:SyS_close                              | 0          | 27         |
>>>>> | backtrace:cpu_startup_entry                      | 0          | 19         |
>>>>> | backtrace:watchdog                               | 0          | 27         |
>>>>> | RIP:__lock_acquire                               | 0          | 2          |
>>>>> | backtrace:rpc_async_schedule                     | 0          | 2          |
>>>>> | backtrace:lock_acquire                           | 0          | 1          |
>>>>> | RIP:delay_tsc                                    | 0          | 1          |
>>>>> | backtrace:SYSC_epoll_wait                        | 0          | 1          |
>>>>> | backtrace:SyS_epoll_wait                         | 0          | 1          |
>>>>> | RIP:pvclock_clocksource_read                     | 0          | 1          |
>>>>> | RIP:xs_reclassify_socket                         | 0          | 1          |
>>>>> | backtrace:xs_tcp_setup_socket                    | 0          | 2          |
>>>>> | RIP:insert_work                                  | 0          | 1          |
>>>>> +--------------------------------------------------+------------+------------+
>>>>
>>>> We recently found this patch cause NFS hang in 0day/LKP test system.
>>>> The NFS export can be mounted, but after a while all read/write to NFS
>>>> mount blocked.  This influenced the 0day/LKP testing.  Could you help us
>>>> to fix this?
>>>>
>>>> Best Regards,
>>>> Huang, Ying
>>>
>>>
>>> I need to officially submit this patch :
>>> http://www.spinics.net/lists/netdev/msg375777.html
>>
>> Thanks a lot!  The patch fixed our NFS hang.
>>
>> Tested-by: Huang, Ying <ying.huang@xxxxxxxxx>
>>
>> Is it possible to put the fixing patch near (preferably next) the patch
>> trigger regression?  Otherwise a bigger range of patches will not be
>> bisectable.
>
> Hi, Eric,
>
> Is it possible for this to be fixed in linux-next ASAP?  This has
> blocked us (0day functionality and performance test) from testing
> linux-next and many other git trees for near 1 week.  Because NFS is
> used in our test infrastructure to save test result data.
>
> Best Regards,
> Huang, Ying