On Sat, 3 Feb 2018, Paul E. McKenney wrote: > Please see below for an initial patch to this effect. This activity > proved to be more productive than expected for these tests, which certainly > supports our assertion that locking needs more testing... > > MP+polocks.litmus > MP+porevlocks.litmus > > These are allowed by the current model, which surprised me a bit, > given that even powerpc would forbid them. Is the rationale > that a lock-savvy compiler could pull accesses into the lock's > critical section and then reorder those accesses? Or does this > constitute a bug in our model of locking? > > (And these were allowed when I wrote recipes.txt, embarrassingly > enough...) > > Z6.0+pooncelock+poonceLock+pombonce.litmus > > This was forbidden when I wrote recipes.txt, but now is allowed. > The header comment for smp_mb__after_spinlock() makes it pretty > clear that it must be forbidden. So this one is a bug in our > model of locking. I just tried testing these under the most recent version of herd, and all three were forbidden. Alan
