There are StackWatermark handling inside LockStack::contains. This is an indication that either, some thread has failed to start its own StackWatermark processing, or that some thread is looking into the oops of another thread without starting the StackWatermark handling. The later is usually more common.

I propose that we hoist the StackWatermark processing out of the LockStack into the code that actually performs these reads of the oops.