[RFC PATCH 0/5] arm64: Signal context expansion

[Florian Weimer]

On 09/09/2016 04:15 PM, Dave Martin wrote:
> This new record can be added in sigframe.__reserved[] if there is a
> need to allocate extra space beyond the standard signal frame.  The
> extra block of memory referenced by extra_context can then be parsed in
> the same way as sigcontext.__reserved[].  Old code should just ignore
> the whole thing as an unrecognised record.  To maintain backward
> compatibility, signal context records defined today are always placed
> directly in __reserved[], never in the block referenced by
> extra_context.

Do you add this extra information only if the stack is sufficiently large?

x86_64 adds the new information even for small stacks set up with 
sigaltstack, leading to memory corruption on bleeding-edge hardware:

   <https://bugzilla.kernel.org/show_bug.cgi?id=153531>

Thanks,
Florian