Re: using valgrind on a loadable builtin

[Robert E. Griffith]

Oh! That makes sense now. Thanks. I was inspecting the memory and was 
confused that it did not seem to use the same chunk structure of the 
glibc malloc.

--BobG

On 5/25/22 18:19, Eduardo Bustamante wrote:
> On Wed, May 25, 2022 at 10:44 AM Robert E. Griffith <bobg@junga.com> 
> wrote:
>
>     I am trying to to use valgrind memcheck on my loadable builtin
>     which is
>     getting a "corrupted size vs. prev_size" error but its output is
>     suspiciously clean and when I use the -v (verbose) switch I do not
>     see
>     any msg about my builtin's .so being loaded even though I do see
>     confirmation that the builtin gets loaded and ran in the output. So I
>     suspect that it is not monitoring my .so.
>
>     I am running it like...
>
>         valgrind -v  ../../bashParse/bash -c  'bg-dev tests run
>     bg_objects.sh:'
>
>     The script enables my builtin.
>
>     bash and my builtin are being built with -g and no -O<n>
>
>     Anyone have any tips on getting meaningful output from valgrind for a
>     loadable builtin?
>
>
> Bash provides its own (lib/malloc/) malloc implementation.  When 
> building bash, you can provide --without-bash-malloc to the configure 
> script to instead link against the libc malloc. You can search for see 
> opt_bash_malloc in "configure", or the USING_BASH_MALLOC macro.
>
> You can review these files to see how it's all hooked 
> up: builtins.h, general.h, xmalloc.h
>
> Valgrind is not capable of tracing the malloc that Bash provides.