[erlang-bugs] Segmentation Fault R13B01

[Rickard Green]

We've not been able to reproduce this. Next time you get a core, please 
make the core and the beam.smp file (located in 
lib/erlang/erts-5.7.2/bin) available for us. Also include info about 
linux distribution, kernel version, hw arch, and gcc version used.

Regards,
Rickard
-- 
Rickard Green, Erlang/OTP, Ericsson AB.

Cliff Moon wrote:
> <div class="moz-text-flowed" style="font-family: -moz-fixed">What's the 
> status on this issue?  I've seen this behavior before as well.  It seems 
> to be a concurrency issue with active TCP packet delivery.  You can 
> pretty easily reproduce the issue using the janus app found here:
> 
> http://github.com/cliffmoon/janus/tree/master
> 
> You need to test on a linux machine with a lot of CPU's to see it happen 
> with any frequency.  I've found that 8 cores or more is enough to see it 
> happen after a few tries.  Using an EC2 high cpu XL instance seems to do 
> the trick.  Basically just start up the server in one VM like this: 
> `make run1` and startup the workers by doing `make sh` and issuing the 
> erlang command bot:test(flashbot, 10000).
> 
> You have a pretty good chance of seeing one of the VM's segfault.  If 
> not you need to restart the VM and start from scratch.  When I run this 
> with gdb I get a similar backtrace to what was previously mentioned in 
> this thread, in that it appears to be a problem in active tcp delivery.
> 
> 
> ------------------------------------------------------------------------------------------ 
> 
> 
>    Hi,I build erlang using gcc 4.1.2 (the default for centos)
>    I started erl using
>     -env ERL_MAX_PORTS 110000 +K true +P 110000 +S4 -smp -detached
> 
>    You can download 3 core dumps
>    http://94.75.214.130/core.12514.gz
>    http://94.75.214.130/core.939.gz
>    http://94.75.214.130/core.28223.gz
> 
>    Unfortunately, i have no clue which part of the code triggers the
>    segfault, other than it happens constantly, and i
>    can not redistribute the whole program. The program though uses
>    heavily tcp
>    connections, typically i have over
>    10k established tcp connections.
> 
>    I would try to build the debug emulator tonight and let you know if
>    i find
>    something.
> 
>    Thanks,
>    Georgos
> 
>    2009/7/1 Raimo Niskanen
>    
> <raimo+erlang-bugs@REDACTED<raimo%2Berlang-bugs@REDACTED>
>     >
> 
>     > On Wed, Jul 01, 2009 at 05:25:14PM +0200, Georgos Siganos wrote:
>     > > Hi All,I am having problems with R13B01 and segmentation
>    faults, as the
>     > > following one (in the bottom).
>     > > Unfortunately, i am not sure which part of the code triggers the
>     > > segmentation fault.
>     > >
>     > > I am running Centos 5.3 ( 2.6.18-128.1.16.el5 #1 SMP x86_64 )
>    on a quad
>     > core
>     > > intel processor.
>     > > The program quits with segfault both when compiled with and
>    without hipe.
>     > >
>     > > Please let me know if there is anything else i can report to
>    fix this
>     > > problem. This
>     > > segmentation
>     > > fault is quite consistent and is a show stopper for my code.
>     > > Thanks,
>     > > Georgos
>     >
>     > How did you build the Erlang emulator, how did you start it
>     > (arguments), how did you provoke the segfault?
>     >
>     > Can you post the code that provokes this to see
>     > if it is reproducable on other OS:es?
>     >
>     > Can you post the core dump for the Erlang/OTP team to dissect?
>     >
>     > Can you build and run a debug emulator and see if you get an earlier
>     > fault detection? (gmake smp TYPE=debug in the emulator directory)
>     >
>     > >
>     > >
>     > > ----------------------- gdb output --------------------------
>     > > Program terminated with signal 11, Segmentation fault.
>     > > [New process 12531]
>     > > [New process 12533]
>     > > [New process 12532]
>     > > [New process 12530]
>     > > [New process 12526]
>     > > [New process 12517]
>     > > [New process 12516]
>     > > [New process 12514]
>     > > #0  0x00002add1f7b570b in memcpy () from /lib64/libc.so.6
>     > > (gdb) bt
>     > > #0  0x00002add1f7b570b in memcpy () from /lib64/libc.so.6
>     > > #1  0x0000000000486849 in driver_deliver_term (port=<value
>    optimized
>     > out>,
>     > > to=4816451, data=<value optimized out>,
>     > >     len=<value optimized out>) at beam/io.c:2994
>     > > #2  0x00000000005513cf in tcp_deliver (desc=0x2aab17c17548,
>    len=3) at
>     > > drivers/common/inet_drv.c:2980
>     > > #3  0x0000000000551891 in tcp_recv (desc=0x2aab17c17548,
>    request_len=0)
>     > at
>     > > drivers/common/inet_drv.c:8043
>     > > #4  0x0000000000551afc in tcp_inet_drv_input (data=0x2aaae21a9fc4,
>     > > event=<value optimized out>) at drivers/common/inet_drv.c:8381
>     > > #5  0x00000000004a3d78 in erts_port_task_execute
>    (runq=0x2add1fc19340,
>     > > curr_port_pp=0x2aaaaaacb1e8) at beam/erl_port_task.c:853
>     > > #6  0x000000000049ebc5 in schedule (p=0x349, calls=<value
>    optimized out>)
>     > at
>     > > beam/erl_process.c:6116
>     > > #7  0x0000000000505afd in process_main () at beam/beam_emu.c:1126
>     > > #8  0x0000000000499126 in sched_thread_func (vesdp=<value
>    optimized out>)
>     > at
>     > > beam/erl_process.c:3015
>     > > #9  0x000000000057a0f4 in thr_wrapper (vtwd=<value optimized
>    out>) at
>     > > common/ethread.c:475
>     > > #10 0x00002add1f31b367 in start_thread () from
>    /lib64/libpthread.so.0
>     > > #11 0x00002add1f80cf7d in clone () from /lib64/libc.so.6
>     > >
>     >
>    
> ---------------------------------------------------------------------------
>     >
>     > --
>     >
>     > / Raimo Niskanen, Erlang/OTP, Ericsson AB
>     >
> 
> 
> 
> </div>


-- 
Rickard Green, Erlang/OTP, Ericsson AB.