Re: armv8 does not respect personality ADDR_LIMIT_3GB
On Tue, Oct 05, 2021 at 04:17:51PM -0400, Jeffrey Walton wrote:
> On Tue, Oct 5, 2021 at 4:00 PM Lennart Sorensen
> <lsorense@csclub.uwaterloo.ca> wrote:
> >
> > ...
> > This fixnum idea in gcl is broken. It must go away. Pointers are for
> > addresses and nothing else.
>
> +1. Tagged pointers caused a lot of problems porting some packages to
> Aarch64. Tagged pointers were blocking a number of web related
> packages. It also caused a number of CVEs, like CVE-2020-9391.
And I found this post:
https://lore.kernel.org/lkml/20081006132651.GG3180@one.firstfloor.org/
where Andi Kleen calls the need for ADDR_LIMIT_3GB "a kludge for
bug-to-bug compatibility with old binaries (that is where the 3GB
personality came from to work around bugs in some old JVMs that could
not deal with a full 4GB address space), it shouldn't be really used
for anything new." And that was 13 years ago. Seems some code still
isn't fixed. Not working with a full 4GB address space is considered
a bug and should be treated as such.
--
Len Sorensen
Reply to: