Re: How to disable leak check from inside a program

On Fri, 2020-05-22 at 15:22 +0300, Michael Widenius wrote:
> Hi!
> I have searched documentation, internet and header files like
> memcheck.h, but not found a solution:
> 
> When running the MariaDB test suite under valgrind, we sometimes may
> get a core dump.  In this case, the leaked memory report can be very
> long and will be totally useless.
> 
> What would help a lot is to have a VALGRIND request, like
> VALGRIND_DO_CLIENT_REQUEST_STMT, that we could use in our signal
> handler to turn off leak checking.
> 
> Is that possible and if not, is that something that could get
> implemented in the future?
> Is this something that anyone else has ever requested ?
> 
> Regards,
> Monty

Hello,

The next version of valgrind is almost ready (Release Candidate was produced
a few days ago).

This release contains a feature to dynamically change many options.

You can obtain the list of dynamically changeable options doing:

 valgrind --help-dyn-options

For memcheck, this gives the below help.
Based on this, you should be able to obtain what you need.

Hope this helps

Philippe


valgrind --help-dyn-options
Some command line settings are "dynamic", meaning they can be changed
while Valgrind is running, like this:
    From the shell, using vgdb. Example:
      $ vgdb "v.clo --trace-children=yes --child-silent-after-fork=no"
    From a gdb attached to the valgrind gdbserver. Example:
      (gdb) monitor v.clo --trace-children=yes --child-silent-after-fork=no"
    From your program, using a client request. Example:
      #include <valgrind/valgrind.h>
      VALGRIND_CLO_CHANGE("--trace-children=yes");
      VALGRIND_CLO_CHANGE("--child-silent-after-fork=no");

  dynamically changeable options:
    -v --verbose -q --quiet -d --stats --vgdb=no --vgdb=yes --vgdb=full
    --vgdb-poll --vgdb-error --vgdb-stop-at --error-markers --show-error-list -s
    --show-below-main --time-stamp --trace-children --child-silent-after-fork
    --trace-sched --trace-signals --trace-symtab --trace-cfi --debug-dump=syms
    --debug-dump=line --debug-dump=frames --trace-redir --trace-syscalls
    --sym-offsets --progress-interval --merge-recursive-frames
    --vex-iropt-verbosity --suppressions --trace-flags --trace-notbelow
    --trace-notabove --profile-flags --gen-suppressions=no
    --gen-suppressions=yes --gen-suppressions=all --errors-for-leak-kinds
    --show-leak-kinds --leak-check-heuristics --show-reachable
    --show-possibly-lost --freelist-vol --freelist-big-blocks --leak-check=no
    --leak-check=summary --leak-check=yes --leak-check=full --ignore-ranges
    --ignore-range-below-sp --show-mismatched-frees
valgrind: Use --help for more information.