[PATCH v2 2/2] arm64: stacktrace: Relax frame record alignment requirement to 8 bytes

[Peter Collingbourne]

On Tue, Dec 1, 2020 at 9:28 AM Catalin Marinas <catalin.marinas at arm.com> wrote:
>
> On Fri, Nov 20, 2020 at 06:32:35PM -0800, Peter Collingbourne wrote:
> > On Mon, Oct 26, 2020 at 2:00 PM Peter Collingbourne <pcc at google.com> wrote:
> > > The AAPCS places no requirements on the alignment of the frame
> > > record. In theory it could be placed anywhere, although it seems
> > > sensible to require it to be aligned to 8 bytes. With an upcoming
> > > enhancement to tag-based KASAN Clang will begin creating frame records
> > > located at an address that is only aligned to 8 bytes. Accommodate
> > > such frame records in the stack unwinding code.
> > >
> > > As pointed out by Mark Rutland, the userspace stack unwinding code
> > > has the same problem, so fix it there as well.
> >
> > As a reminder, this series is required in order to avoid breaking
> > stack traces once [1] is applied.
> >
> > Peter
> >
> > [1] https://lore.kernel.org/linux-arm-kernel/20201120230211.584929-1-pcc@google.com/T/
>
> While this series looks fine, on its own it doesn't solve any issue we
> currently have. So, could you please post this series together with the
> outlined tags mismatch checks patch? I think they should be merged
> together.
>
> Thanks.

Done (as also requested by Mark Rutland) in v3 of that series.

Peter