[petsc-users] Memory leak when combining PETSc-based vectors and boost::odeint

[Roland Richter]

Hei,

Thanks for the idea! I added a simple std::cout for both constructor and
destructor, and found out that my destructor is called multiple times,
while the constructor is called only once. This could explain the error
(double free), but I do not know why segfault is thrown even though I
explicitly check if the vector has been used. Are there explanations for
that?

Regards,

Roland Richter

Am 31.03.22 um 12:14 schrieb Matthew Knepley:
> On Thu, Mar 31, 2022 at 5:58 AM Roland Richter
> <roland.richter at ntnu.no> wrote:
>
>     Hei,
>
>     For a project I wanted to combine boost::odeint for timestepping
>     and PETSc-based vectors and matrices for calculating the right
>     hand side. As comparison for both timing and correctness I set up
>     an armadillo-based right hand side (with the main-function being
>     in *main.cpp*, and the test code in *test_timestepping_clean.cpp*)
>
>     In theory, the code works fine, but I have some issues with
>     cleaning up afterwards in my struct /Petsc_RHS_state_clean/. My
>     initial intention was to set up all involved matrices and vectors
>     within the constructor, and free the memory in the destructor. To
>     avoid freeing vectors I have not used I initially set them to
>     /PETSC_NULL/, and check if this value has been changed before
>     calling /VecDestroy()./
>
> You do not need to check. Destroy() functions already check for NULL.
>
>     However, when doing that I get the following 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 https://petsc.org/release/faq/#valgrind
>     [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.
>     [0]PETSC ERROR: --------------------- Error Message
>     --------------------------------------------------------------
>
>     If I comment out that code in ~Petsc_RHS_state_clean(), the
>     program runs, but will use ~17 GByte of RAM during runtime. As the
>     memory is not used immediately in full, but rather increases
>     during running, I assume a memory leak somewhere. Where does it
>     come from, and how can I avoid it?
>
> It must be that your constructor is called multiple times without
> calling your destructor. I cannot understand this code in order
> to see where that happens, but you should just be able to run in the
> debugger and put a break point at the creation and
> destruction calls.
>
>   Thanks,
>
>       Matt
>
>     Thanks!
>
>     Regards,
>
>     Roland Richter
>
>
>
> -- 
> 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
>
> https://www.cse.buffalo.edu/~knepley/
> <http://www.cse.buffalo.edu/~knepley/>
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