[petsc-users] a crash due to memory issue

[Matthew Knepley]

On Sat, Apr 30, 2016 at 10:04 AM, Ilyas YILMAZ <ilyascfd at gmail.com> wrote:

> Hello,
>
> The code segment I wrote based on "src/dm/da/examples/tutorials/ex2.c"
> crashes when destroying things / freeing memory as given below.
> I can't figure out what I'm missing? Any comments are welcome. (Petsc
> 3.1.p8, intel fortran compiler). The code and error are below.
>
>         !...Create scatter from global DA parallel vector to local vector
> that contains all entries
>         call DAGlobalToNaturalAllCreate(da,tolocalall,ierr)
>         call DAGlobalToNaturalAllCreate(da,tolocalall2,ierr)
>         call DAGlobalToNaturalAllCreate(da,tolocalall3,ierr)
>

1) Why are you doing this? There does not seem to be any need for it.

2) Always run with debugging until your code works

3) If you get an SEGV, run with valgrind (http://www.valgrind.org)

   Matt


>         call VecCreateSeq(PETSC_COMM_SELF,im*jm*km,CSRENOMlocalall,ierr)
>         call
> VecScatterBegin(tolocalall,CSRENOM,CSRENOMlocalall,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecScatterEnd(
> tolocalall,CSRENOM,CSRENOMlocalall,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecCreateSeq(PETSC_COMM_SELF,im*jm*km,CSDENOMlocalall,ierr)
>         call
> VecScatterBegin(tolocalall2,CSDENOM,CSDENOMlocalall,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecScatterEnd(
> tolocalall2,CSDENOM,CSDENOMlocalall,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecCreateSeq(PETSC_COMM_SELF,im*jm*km,CSlocalall,ierr)
>         call
> VecScatterBegin(tolocalall3,CS,CSlocalall,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecScatterEnd(
> tolocalall3,CS,CSlocalall,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>
>         call
> VecGetArray(CSRENOMlocalall,scaCSRENOMlocalall,idCSRENOMlocalall,ierr)
>         call
> VecGetArray(CSDENOMlocalall,scaCSDENOMlocalall,idCSDENOMlocalall,ierr)
>         call VecGetArray(     CSlocalall,scaCSlocalall
> ,idCSlocalall     ,ierr)
>
>
>                           SOME WORK HERE
>
>
>         call VecRestoreArray(CSlocalall     ,scaCSlocalall
> ,idCSlocalall,ierr)
>         call
> VecRestoreArray(CSRENOMlocalall,scaCSRENOMlocalall,idCSRENOMlocalall,ierr)
>         call
> VecRestoreArray(CSDENOMlocalall,scaCSDENOMlocalall,idCSDENOMlocalall,ierr)
>
>
>         !...scatter back to global vector
>         call DANaturalAllToGlobalCreate(da,fromlocalall,ierr)
>         call DANaturalAllToGlobalCreate(da,fromlocalall2,ierr)
>         call DANaturalAllToGlobalCreate(da,fromlocalall3,ierr)
>
>         call
> VecScatterBegin(fromlocalall,CSRENOMlocalall,CSRENOM,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecScatterEnd(
> fromlocalall,CSRENOMlocalall,CSRENOM,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call
> VecScatterBegin(fromlocalall2,CSDENOMlocalall,CSDENOM,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecScatterEnd(
> fromlocalall2,CSDENOMlocalall,CSDENOM,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call
> VecScatterBegin(fromlocalall3,CSlocalall,CS,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         call VecScatterEnd(
> fromlocalall3,CSlocalall,CS,INSERT_VALUES,SCATTER_FORWARD,ierr)
>
>         !..free memory
>        call VecScatterDestroy(fromlocalall,ierr)
>        call VecScatterDestroy(fromlocalall2,ierr)
>        call VecScatterDestroy(fromlocalall3,ierr)
>
>       call VecScatterDestroy(tolocalall,ierr)
>       call VecScatterDestroy(tolocalall2,ierr)
>       call VecScatterDestroy(tolocalall3,ierr)
>
>       call VecDestroy(CSDENOMlocalall,ierr)
>       call VecDestroy(CSRENOMlocalall,ierr)
>       call VecDestroy(CSlocalall,ierr)
>
>
> .
> .
> .
> .
> .
> .
>  ...................... SGS model is called
>  MUT computed
>  MUT computed
>  MUT computed
>  MUT computed
> [1]PETSC ERROR:
> ------------------------------------------------------------------------
> [1]PETSC ERROR: [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation,
> probably memory access out of range
> [0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
> [0]PETSC ERROR: or see
> http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal[0]PETSC
> ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find
> memory corruption errors
> [0]PETSC ERROR: configure using --with-debugging=yes, recompile, link, and
> run
> [0]PETSC ERROR: to get more information on the crash.
> .
> .
> .
> .
> .
>
> Thank you
>
> Ilyas.
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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