[PATCH 0/7] RFC Memory tagging support

DJ Delorie dj@redhat.com
Mon Jun 15 17:22:55 GMT 2020


Richard Earnshaw <Richard.Earnshaw@foss.arm.com> writes:
>> 2. Do we really need to lose the back pointer's word in allocated
>>    memory?  Historically, the back pointer is *not* part of the malloc
>>    internal data when the chunk is in 'allocated' state, and losing that
>>    memory will make small allocations much less efficient.
>
> Yes, if you want to protect the back pointer against being trampled by
> programs - it has to have a different tag colour to memory given to the
> application.

But is there a way to recolor it when allocated?  It only need be
protected when the chunk is in malloc's control.  In fact, when the
application has it, it should be colored differently than malloc's data,
to prevent malloc from trying to use it.



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