[erlang-bugs] VM locks up on write to socket (and now it seems to file too)

Peter Membrey <>
Thu Nov 29 04:41:42 CET 2012


Hi Patrik,

I can also confirm that this bug exists on Red Hat Enterprise Linux
6.3. I'll raise a support ticket with them as well.

A workaround in the vm would be nice if you have time… :-)

Cheers,

Pete


On 29 November 2012 01:23, Patrik Nyblom <> wrote:
> Hi again!
>
> No problem reproducing when I've got CentOS 6.3... The following commands in
> the Erlang shell:
> {ok,L} = gen_tcp:listen(4747,[{active,false}]).
> {ok,S} = gen_tcp:connect("localhost",4747,[{active,false}]).
> {ok,A} = gen_tcp:accept(L).
> gen_tcp:send(A,binary:copy(<<$a:8>>,2158022464)).
>
> gives the following strace:
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [pid 15859] writev(10, [{"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"...,
> 2158022464}], 1) = 0
> [.....]
>
> While on ubuntu for example it works like it should...Looks like a kernel
> bug to me... I wonder if this should be worked around or just reported... I
> suppose both... Sigh...
>
> /Patrik
>
>
> On 11/28/2012 05:23 PM, Peter Membrey wrote:
>>
>> Hi,
>>
>> No problem, I'll do what I can to help - thanks for looking into this
>> so quickly!
>>
>> Any idea what might be causing it?
>>
>> Cheers,
>>
>> Pete
>>
>> On 28 November 2012 23:54, Patrik Nyblom <> wrote:
>>>
>>> Hi!
>>>
>>> I'll upgrade the CentOS VM I have to 6.3 (only had 6.1 :() and see if I
>>> can
>>> reproduce. If that fails, could you run a VM with a patch to try to
>>> handle
>>> the unexpected case and see if that fixes it?
>>>
>>> Cheers,
>>> /Patrik
>>>
>>> On 11/24/2012 02:57 PM, Peter Membrey wrote:
>>>>
>>>> Hi guys,
>>>>
>>>> Thanks for getting back in touch so quickly!
>>>>
>>>> I did do an lsof on the process and I can confirm that it was
>>>> definitely a socket. However by that time the application it had been
>>>> trying to send to had been killed. When I checked the sockets were
>>>> showing as waiting to close. Unfortunately I didn't think to do an
>>>> lsof until after the apps had been shut down. I was hoping the VM
>>>> would recover if I killed the app that had upset it. However even
>>>> after all the apps connected had been shut down, the issue didn't
>>>> resolve.
>>>>
>>>> The application receives requests from a client, which contains two
>>>> data items. The stream ID and a timestamp. Both are encoded as big
>>>> integer unsigned numbers. The server then looks through the file
>>>> referenced by the stream ID and uses the timestamp as an index. The
>>>> file format is currently really simple, in the form of:
>>>>
>>>>
>>>> <Timestamp:64/native-integer,Length:32/native-integer,Data:Length/binary>>
>>>>
>>>> There is an index file that provides an offset into the file based on
>>>> time stamp, but basically it opens the file, and reads sequentially
>>>> through it until it finds the timestamps that it cares about. In this
>>>> case it reads all data with a greater timestamp until the end of the
>>>> file is reached. It's possible the client is sending an incorrect
>>>> timestamp, and maybe too much data is being read. However the loop is
>>>> very primitive - it reads all the data in one go before passing it
>>>> back to the protocol handler to send down the socket; so by that time
>>>> even though the response is technically incorrect and the app has
>>>> failed, it should still not cause the VM any issues.
>>>>
>>>> The data is polled every 10 seconds by the client app so I would not
>>>> expect there to be 2GB of new data to send. I'm afraid my C skills are
>>>> somewhat limited, so I'm not sure how to put together a sample app to
>>>> try out writev. The platform is 64bit CentOS 6.3 (equivalent to RHEL
>>>> 6.3) so I'm not expecting any strange or weird behaviour from the OS
>>>> level but of course I could be completely wrong there. The OS is
>>>> running directly on hardware, so there's no VM layer to worry about.
>>>>
>>>> Hope this might offer some additional clues…
>>>>
>>>> Thanks again!
>>>>
>>>> Kind Regards,
>>>>
>>>> Peter Membrey
>>>>
>>>>
>>>>
>>>> On 24 November 2012 00:13, Patrik Nyblom <> wrote:
>>>>>
>>>>> Hi again!
>>>>>
>>>>> Could you go back to the version without the printouts and get back to
>>>>> the
>>>>> situation where writev loops returning 0 (as in the strace)? If so, it
>>>>> would
>>>>> be really interesting to see an 'lsof' of the beam process, to see if
>>>>> this
>>>>> file descriptor really is open and is a socket...
>>>>>
>>>>> The thing is that writev with a vector that is not empty, would never
>>>>> return
>>>>> 0 for a non blocking socket. Not on any modern (i.e. not ancient) POSIX
>>>>> compliant system anyway. Of course it is a *really* large item you are
>>>>> trying to write there, but it should be no problem for a 64bit linux.
>>>>>
>>>>> Also I think there is no use finding the Erlang code, I'll take that
>>>>> back,
>>>>> It would be more interesting to see what really happens at the OS/VM
>>>>> level
>>>>> in this case.
>>>>>
>>>>> Cheers,
>>>>> Patrik
>>>>>
>>>>>
>>>>> On 11/23/2012 01:49 AM, Loïc Hoguin wrote:
>>>>>>
>>>>>> Sending this on behalf of someone who didn't manage to get the email
>>>>>> sent
>>>>>> to this list after 2 attempts. If someone can check if he's hold up or
>>>>>> something that'd be great.
>>>>>>
>>>>>> Anyway he has a big issue so I hope I can relay the conversation
>>>>>> reliably.
>>>>>>
>>>>>> Thanks!
>>>>>>
>>>>>> On 11/23/2012 01:45 AM, Peter Membrey wrote:
>>>>>>>
>>>>>>> From: Peter Membrey <>
>>>>>>> Date: 22 November 2012 19:02
>>>>>>> Subject: VM locks up on write to socket (and now it seems to file
>>>>>>> too)
>>>>>>> To: 
>>>>>>>
>>>>>>>
>>>>>>> Hi guys,
>>>>>>>
>>>>>>> I wrote a simple database application called CakeDB
>>>>>>> (https://github.com/pmembrey/cakedb) that basically spends its time
>>>>>>> reading and writing files and sockets. There's very little in the way
>>>>>>> of complex logic. It is running on CentOS 6.3 with all the updates
>>>>>>> applied. I hit this problem on R15B02 so I rolled back to R15B01 but
>>>>>>> the issue remained. Erlang was built from source.
>>>>>>>
>>>>>>> The machine has two Intel X5690 CPUs giving 12 cores plus HT. I've
>>>>>>> tried various arguments for the VM but so far nothing has prevented
>>>>>>> the problem. At the moment I'm using:
>>>>>>>
>>>>>>> +K
>>>>>>> +A 6
>>>>>>> +sbt tnnps
>>>>>>>
>>>>>>> The issue I'm seeing is that one of the scheduler threads will hit
>>>>>>> 100% cpu usage and the entire VM will become unresponsive. When this
>>>>>>> happens, I am not able to connect via the console with attach and
>>>>>>> entop is also unable to connect. I can still establish TCP
>>>>>>> connections
>>>>>>> to the application, but I never receive a response. A standard kill
>>>>>>> signal will cause the VM to shut down (it doesn't need -9).
>>>>>>>
>>>>>>> Due to the pedigree of the VM I am quite willing to accept that I've
>>>>>>> made a fundamental mistake in my code. I am pretty sure that the way
>>>>>>> I
>>>>>>> am doing the file IO could result in some race conditions. However,
>>>>>>> my
>>>>>>> poor code aside, from what I understand, I still shouldn't be able to
>>>>>>> crash / deadlock the VM like this.
>>>>>>>
>>>>>>> The issue doesn't seem to be caused by load. The app can fail when
>>>>>>> it's very busy, but also when it is practically idle. I haven't been
>>>>>>> able to find a trigger or any other explanation for the failure.
>>>>>>>
>>>>>>> The thread maxing out the CPU is attempting to write data to the
>>>>>>> socket:
>>>>>>>
>>>>>>> (gdb) bt
>>>>>>> #0  0x00007f9882ab6377 in writev () from /lib64/libc.so.6
>>>>>>> #1  0x000000000058a81f in tcp_inet_output (data=0x2407570,
>>>>>>> event=<value optimized out>) at drivers/common/inet_drv.c:9681
>>>>>>> #2  tcp_inet_drv_output (data=0x2407570, event=<value optimized out>)
>>>>>>> at drivers/common/inet_drv.c:9601
>>>>>>> #3  0x00000000004b773f in erts_port_task_execute
>>>>>>> (runq=0x7f98826019c0,
>>>>>>> curr_port_pp=0x7f9881639338)  at beam/erl_port_task.c:858
>>>>>>> #4  0x00000000004afd83 in schedule (p=<value optimized out>,
>>>>>>> calls=<value optimized out>) at beam/erl_process.c:6533
>>>>>>> #5  0x0000000000539ca2 in process_main () at beam/beam_emu.c:1268
>>>>>>> #6  0x00000000004b1279 in sched_thread_func (vesdp=0x7f9881639280) at
>>>>>>> beam/erl_process.c:4834
>>>>>>> #7  0x00000000005ba726 in thr_wrapper (vtwd=0x7fff6cfe2300) at
>>>>>>> pthread/ethread.c:106
>>>>>>> #8  0x00007f9882f78851 in start_thread () from /lib64/libpthread.so.0
>>>>>>> #9  0x00007f9882abe11d in clone () from /lib64/libc.so.6
>>>>>>> (gdb)
>>>>>>>
>>>>>>> I then tried running strace on that thread and got (indefinitely):
>>>>>>>
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> writev(15, [{"", 2158022464}], 1)       = 0
>>>>>>> ...
>>>>>>>
>>>>>>>    From what I can tell, it's trying to write data to a socket, which
>>>>>>> is
>>>>>>> succeeding, but writing 0 bytes. From the earlier definitions in the
>>>>>>> source file, an error condition would be signified by a negative
>>>>>>> number. Any other result is the number of bytes written, in this case
>>>>>>> 0. I'm not sure if this is desired behaviour or not. I've tried
>>>>>>> killing the application on the other end of the socket, but it has no
>>>>>>> effect on the VM.
>>>>>>>
>>>>>>> I have enabled debugging for the inet code, so hopefully this will
>>>>>>> give a little more insight. I am currently trying to reproduce the
>>>>>>> condition, but as I really have no idea what causes it, it's pretty
>>>>>>> much a case of wait and see.
>>>>>>>
>>>>>>>
>>>>>>> **** UPDATE ****
>>>>>>>
>>>>>>> I managed to lock up the VM again, but this time it was caused by
>>>>>>> file
>>>>>>> IO,
>>>>>>> probably from the debugging statements. Although it worked fine for
>>>>>>> some
>>>>>>> time
>>>>>>> the last entry in the file was cut off.
>>>>>>>
>>>>>>>    From GDB:
>>>>>>>
>>>>>>> (gdb) info threads
>>>>>>>      53 Thread 0x7f83e988b700 (LWP 8621)  0x00007f83ea6da54d in read
>>>>>>> ()
>>>>>>> from /lib64/libpthread.so.0
>>>>>>>      52 Thread 0x7f83e8c8f700 (LWP 8622)  0x00007f83ea6d743c in
>>>>>>> pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
>>>>>>>      51 Thread 0x7f83e818d700 (LWP 8623)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      50 Thread 0x7f83e816b700 (LWP 8624)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      49 Thread 0x7f83e8149700 (LWP 8625)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      48 Thread 0x7f83e8127700 (LWP 8626)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      47 Thread 0x7f83e8105700 (LWP 8627)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      46 Thread 0x7f83e80e3700 (LWP 8628)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      45 Thread 0x7f83e80c1700 (LWP 8629)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      44 Thread 0x7f83e809f700 (LWP 8630)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      43 Thread 0x7f83e807d700 (LWP 8631)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      42 Thread 0x7f83e805b700 (LWP 8632)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      41 Thread 0x7f83e8039700 (LWP 8633)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      40 Thread 0x7f83e8017700 (LWP 8634)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      39 Thread 0x7f83e7ff5700 (LWP 8635)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      38 Thread 0x7f83e7fd3700 (LWP 8636)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      37 Thread 0x7f83e7fb1700 (LWP 8637)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      36 Thread 0x7f83e7f8f700 (LWP 8638)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      35 Thread 0x7f83e7f6d700 (LWP 8639)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      34 Thread 0x7f83e7f4b700 (LWP 8640)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      33 Thread 0x7f83e7f29700 (LWP 8641)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      32 Thread 0x7f83e7f07700 (LWP 8642)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      31 Thread 0x7f83e7ee5700 (LWP 8643)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      30 Thread 0x7f83e7ec3700 (LWP 8644)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      29 Thread 0x7f83e7ea1700 (LWP 8645)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      28 Thread 0x7f83e7e7f700 (LWP 8646)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      27 Thread 0x7f83d7c5a700 (LWP 8647)  0x00007f83ea6db09d in
>>>>>>> waitpid
>>>>>>> () from /lib64/libpthread.so.0
>>>>>>>      26 Thread 0x7f83d7c53700 (LWP 8648)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      25 Thread 0x7f83d7252700 (LWP 8649)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      24 Thread 0x7f83d6851700 (LWP 8650)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      23 Thread 0x7f83d5e50700 (LWP 8651)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      22 Thread 0x7f83d544f700 (LWP 8652)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      21 Thread 0x7f83d4a4e700 (LWP 8653)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      20 Thread 0x7f83d404d700 (LWP 8654)  0x00007f83ea20be7d in write
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      19 Thread 0x7f83d364c700 (LWP 8655)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      18 Thread 0x7f83d2c4b700 (LWP 8656)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      17 Thread 0x7f83d224a700 (LWP 8657)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      16 Thread 0x7f83d1849700 (LWP 8658)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      15 Thread 0x7f83d0e48700 (LWP 8659)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      14 Thread 0x7f83d0447700 (LWP 8660)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      13 Thread 0x7f83cfa46700 (LWP 8661)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      12 Thread 0x7f83cf045700 (LWP 8662)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      11 Thread 0x7f83ce644700 (LWP 8663)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      10 Thread 0x7f83cdc43700 (LWP 8664)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> () from /lib64/libc.so.6
>>>>>>>      9 Thread 0x7f83cd242700 (LWP 8665)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      8 Thread 0x7f83cc841700 (LWP 8666)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      7 Thread 0x7f83cbe40700 (LWP 8667)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      6 Thread 0x7f83cb43f700 (LWP 8668)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      5 Thread 0x7f83caa3e700 (LWP 8669)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      4 Thread 0x7f83ca03d700 (LWP 8670)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      3 Thread 0x7f83c963c700 (LWP 8671)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>>      2 Thread 0x7f83c8c3b700 (LWP 8672)  0x00007f83ea215ae9 in
>>>>>>> syscall
>>>>>>> ()
>>>>>>> from /lib64/libc.so.6
>>>>>>> * 1 Thread 0x7f83eb3a8700 (LWP 8597)  0x00007f83ea211d03 in select ()
>>>>>>> from /lib64/libc.so.6
>>>>>>> (gdb)
>>>>>>>
>>>>>>>
>>>>>>> (gdb) bt
>>>>>>> #0  0x00007f83ea20be7d in write () from /lib64/libc.so.6
>>>>>>> #1  0x00007f83ea1a2583 in _IO_new_file_write () from /lib64/libc.so.6
>>>>>>> #2  0x00007f83ea1a3b35 in _IO_new_do_write () from /lib64/libc.so.6
>>>>>>> #3  0x00007f83ea1a21fd in _IO_new_file_xsputn () from
>>>>>>> /lib64/libc.so.6
>>>>>>> #4  0x00007f83ea17589d in vfprintf () from /lib64/libc.so.6
>>>>>>> #5  0x00007f83ea18003a in printf () from /lib64/libc.so.6
>>>>>>> #6  0x000000000058f0e8 in tcp_recv (desc=0x2c3d350, request_len=0) at
>>>>>>> drivers/common/inet_drv.c:8976
>>>>>>> #7  0x000000000058f63a in tcp_inet_input (data=0x2c3d350,
>>>>>>> event=<value
>>>>>>> optimized out>) at drivers/common/inet_drv.c:9326
>>>>>>> #8  tcp_inet_drv_input (data=0x2c3d350, event=<value optimized out>)
>>>>>>> at drivers/common/inet_drv.c:9604
>>>>>>> #9  0x00000000004b770f in erts_port_task_execute
>>>>>>> (runq=0x7f83e9d5d3c0,
>>>>>>> curr_port_pp=0x7f83e8dc6e78) at beam/erl_port_task.c:851
>>>>>>> #10 0x00000000004afd83 in schedule (p=<value optimized out>,
>>>>>>> calls=<value optimized out>) at beam/erl_process.c:6533
>>>>>>> #11 0x0000000000539ca2 in process_main () at beam/beam_emu.c:1268
>>>>>>> #12 0x00000000004b1279 in sched_thread_func (vesdp=0x7f83e8dc6dc0) at
>>>>>>> beam/erl_process.c:4834
>>>>>>> #13 0x00000000005bb3e6 in thr_wrapper (vtwd=0x7fffe8266da0) at
>>>>>>> pthread/ethread.c:106
>>>>>>> #14 0x00007f83ea6d3851 in start_thread () from /lib64/libpthread.so.0
>>>>>>> #15 0x00007f83ea21911d in clone () from /lib64/libc.so.6
>>>>>>> (gdb)
>>>>>>>
>>>>>>> (gdb) bt
>>>>>>> #0  0x00007f83ea6da54d in read () from /lib64/libpthread.so.0
>>>>>>> #1  0x0000000000554b6e in signal_dispatcher_thread_func
>>>>>>> (unused=<value
>>>>>>> optimized out>) at sys/unix/sys.c:2776
>>>>>>> #2  0x00000000005bb3e6 in thr_wrapper (vtwd=0x7fffe8266c80) at
>>>>>>> pthread/ethread.c:106
>>>>>>> #3  0x00007f83ea6d3851 in start_thread () from /lib64/libpthread.so.0
>>>>>>> #4  0x00007f83ea21911d in clone () from /lib64/libc.so.6
>>>>>>> (gdb)
>>>>>>>
>>>>>>> (gdb) bt
>>>>>>> #0  0x00007f83ea215ae9 in syscall () from /lib64/libc.so.6
>>>>>>> #1  0x00000000005bba35 in wait__ (e=0x2989390) at
>>>>>>> pthread/ethr_event.c:92
>>>>>>> #2  ethr_event_wait (e=0x2989390) at pthread/ethr_event.c:218
>>>>>>> #3  0x00000000004ae5bd in erts_tse_wait (fcalls=<value optimized
>>>>>>> out>,
>>>>>>> esdp=0x7f83e8e2c440, rq=0x7f83e9d5e7c0) at beam/erl_threads.h:2319
>>>>>>> #4  scheduler_wait (fcalls=<value optimized out>,
>>>>>>> esdp=0x7f83e8e2c440,
>>>>>>> rq=0x7f83e9d5e7c0) at beam/erl_process.c:2087
>>>>>>> #5  0x00000000004afb94 in schedule (p=<value optimized out>,
>>>>>>> calls=<value optimized out>) at beam/erl_process.c:6467
>>>>>>> #6  0x0000000000539ca2 in process_main () at beam/beam_emu.c:1268
>>>>>>> #7  0x00000000004b1279 in sched_thread_func (vesdp=0x7f83e8e2c440) at
>>>>>>> beam/erl_process.c:4834
>>>>>>> #8  0x00000000005bb3e6 in thr_wrapper (vtwd=0x7fffe8266da0) at
>>>>>>> pthread/ethread.c:106
>>>>>>> #9  0x00007f83ea6d3851 in start_thread () from /lib64/libpthread.so.0
>>>>>>> #10 0x00007f83ea21911d in clone () from /lib64/libc.so.6
>>>>>>> (gdb)
>>>>>>>
>>>>>>>
>>>>>>> (gdb) bt
>>>>>>> #0  0x00007f83ea6db09d in waitpid () from /lib64/libpthread.so.0
>>>>>>> #1  0x0000000000555a9f in child_waiter (unused=<value optimized out>)
>>>>>>> at sys/unix/sys.c:2700
>>>>>>> #2  0x00000000005bb3e6 in thr_wrapper (vtwd=0x7fffe8266d50) at
>>>>>>> pthread/ethread.c:106
>>>>>>> #3  0x00007f83ea6d3851 in start_thread () from /lib64/libpthread.so.0
>>>>>>> #4  0x00007f83ea21911d in clone () from /lib64/libc.so.6
>>>>>>> (gdb)
>>>>>>>
>>>>>>>
>>>>>>> **** END UPDATE ****
>>>>>>>
>>>>>>>
>>>>>>> I'm happy to provide any information I can, so please don't hesitate
>>>>>>> to
>>>>>>> ask.
>>>>>>>
>>>>>>> Thanks in advance!
>>>>>>>
>>>>>>> Kind Regards,
>>>>>>>
>>>>>>> Peter Membrey
>>>>>>>
>>>>> _______________________________________________
>>>>> erlang-bugs mailing list
>>>>> 
>>>>> http://erlang.org/mailman/listinfo/erlang-bugs
>>>
>>>
>


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