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

Catalin Marinas catalin.marinas at arm.com
Tue Dec 1 12:28:53 EST 2020

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



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