Re: [PATCH v8 13/15] x86/split_lock: Enable split lock detection by default

[Peter Zijlstra]

On Thu, Apr 25, 2019 at 11:13:23AM +0000, David Laight wrote:
> I'm not at all sure that 'compare and exchange' operations
> are atomic on all cpus if the data is misaligned and crosses
> a page boundary and either (or both) pages need faulting in
> (or hit a TLB miss).

Most sane architectures already trap if you attempt that.