[PATCH v3 2/8] elf: Add a tunable to control use of tagged memory

[Szabolcs Nagy]

The 11/26/2020 08:51, H.J. Lu via Libc-alpha wrote:
> On Thu, Nov 26, 2020 at 8:28 AM Richard Earnshaw
> <Richard.Earnshaw@foss.arm.com> wrote:
> > On 26/11/2020 15:50, H.J. Lu wrote:
> > > I think we need to address binary marking first before adding MTE to
> > > glibc.
> >
> > Sorry, I disagree.  While this is a debugging tool there's no need for
> > binary marking.
> >
> > Once we have a clearer understanding of what's needed there, we can work
> > out how best to do the marking.
> 
> If the only goal is to have a malloc with memory tag, you should enable
> memory tag in an out-of-tree malloc implementation.  It should be sufficient.

out-of-tree malloc implementation cannot reliably
enable mte: it cannot guarantee that it can initialize
mte before the process becomes multi-threaded or that
it can execute code in all threads before allocated
memory is accessed there, so mte checks can be off
for some threads.

so the mte on/off setting has to be in glibc for now
(out-of-tree implementation is possible, but it won't
be reliable in all cases).