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Subject: Re: [OMPI users] Open MPI, Segmentation fault
From: Asad Ali (asad06_at_[hidden])
Date: 2010-07-01 03:17:34


Hi Jack,

Debugging OpenMPI with traditional debuggers is a pain.
>From your error message it sounds that you have some memory allocation
problem. Do you use dynamic memory allocation (allocate and then free)?

I use display (printf()) command with MPIrank command. It tells me which
thread is giving segmentation fault.

Cheers,

Asad

On Thu, Jul 1, 2010 at 4:13 PM, Jack Bryan <dtustudy68_at_[hidden]> wrote:

> thanks
>
> I am not familiar with OpenMPI.
>
> Would you please help me with how to ask openMPI to show where the fault
> occurs ?
>
> GNU debuger ?
>
> Any help is appreciated.
>
> thanks!!!
>
> Jack
>
> June 30 2010
>
> ------------------------------
> Date: Wed, 30 Jun 2010 16:13:09 -0400
> From: amjad11_at_[hidden]
> To: users_at_[hidden]
> Subject: Re: [OMPI users] Open MPI, Segmentation fault
>
>
> Based on my experiences, I would FULLY endorse (100% agree with) David
> Zhang.
> It is usually a coding or typo mistake.
>
> At first, Ensure that array sizes and dimension are correct.
>
> I experience that if openmpi is compiled with gnu compilers (not with
> Intel) then it also point outs the subroutine exactly in which the fault
> occur. have a try.
>
> best,
> AA
>
>
>
> On Wed, Jun 30, 2010 at 12:43 PM, David Zhang <solarbikedz_at_[hidden]>wrote:
>
> When I got segmentation faults, it has always been my coding mistakes.
> Perhaps your code is not robust against number of processes not divisible by
> 2?
>
> On Wed, Jun 30, 2010 at 8:47 AM, Jack Bryan <dtustudy68_at_[hidden]>wrote:
>
> Dear All,
>
> I am using Open MPI, I got the error:
>
> n337:37664] *** Process received signal ***
> [n337:37664] Signal: Segmentation fault (11)
> [n337:37664] Signal code: Address not mapped (1)
> [n337:37664] Failing at address: 0x7fffcfe90000
> [n337:37664] [ 0] /lib64/libpthread.so.0 [0x3c50e0e4c0]
> [n337:37664] [ 1]
> /lustre/home/rhascheduler/RhaScheduler-0.4.1.1/mytest/nmn2 [0x414ed7]
> [n337:37664] [ 2] /lib64/libc.so.6(__libc_start_main+0xf4) [0x3c5021d974]
> [n337:37664] [ 3]
> /lustre/home/rhascheduler/RhaScheduler-0.4.1.1/mytest/nmn2(__gxx_personality_v0+0x1f1)
> [0x412139]
> [n337:37664] *** End of error message ***
>
> After searching answers, it seems that some functions fail.
>
> My program can run well for 1,2,10 processors, but fail when the number of
> tasks cannot
> be divided evenly by number of processes.
>
> Any help is appreciated.
>
> thanks
>
> Jack
>
> June 30 2010
>
>
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>
> --
> David Zhang
> University of California, San Diego
>
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