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

[Peter Collingbourne]

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/