On Mon, Feb 12, 2024 at 2:45 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > On Mon, Feb 12, 2024 at 01:39:19PM -0800, Suren Baghdasaryan wrote: > > To avoid debug warnings while freeing reserved pages which were not > > allocated with usual allocators, mark their codetags as empty before > > freeing. > > How do these get their codetags to begin with? The space for the codetag reference is inside the page_ext and that reference is set to NULL. So, unless we set the reference as empty (set it to CODETAG_EMPTY), the free routine will detect that we are freeing an allocation that has never been accounted for and will issue a warning. To prevent this warning we use this CODETAG_EMPTY to denote that this codetag reference is expected to be empty because it was not allocated in a usual way. > Regardless: > > Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > > -- > Kees Cook
