Custom allocators are (or were) common enough that Valgrind includes an API for them to use to tell the analysis engine where the valid memory blocks are: http

Custom allocators are (or were) common enough that Valgrind includes an API for them to use to tell the analysis engine where the valid memory blocks are: https://valgrind.org/docs/manual/mc-manual.html#mc-manual.mempools https://valgrind.org/docs/manual/mc-manual.html#mc-manual.me... I believe the state of the art in generic malloc implementations has improved since this sort of thing was commonplace, though.