"> <@jamesmunns:beeper.com> maybe..." <- > <@jamesmunns:beeper.com> I feel like this should work, but I can't tell you why it doesn't. > > have you guaranteed the kernel is actually doing good ops to the right memory, and it's not a bug somewhere else? and peeked at the asm to see if it is just doing garbage (and maybe diff with compiler fence vs the fence?) So to report back, adding a `compiler_fence(Ordering::Acquire)` does exactly nothing to the assembly. Adding a `fence(Ordering::Acquire)` (or any other ordering) adds a `dmb sy`, and that seems to make my issue go away. Thanks for your help!