WTH did you not Cc the people that commented on your patch last time? On Wed, Aug 23, 2017 at 04:58:55PM +0530, Prateek Sood wrote: > If a spinner is present, there is a chance that the load of > rwsem_has_spinner() in rwsem_wake() can be reordered with > respect to decrement of rwsem count in __up_write() leading > to wakeup being missed.
> spinning writer up_write caller > --------------- ----------------------- > [S] osq_unlock() [L] osq > spin_lock(wait_lock) > sem->count=0xFFFFFFFF00000001 > +0xFFFFFFFF00000000 > count=sem->count > MB > sem->count=0xFFFFFFFE00000001 > -0xFFFFFFFF00000001 > RMB This doesn't make sense, it appears to order a STORE against something else. > spin_trylock(wait_lock) > return > rwsem_try_write_lock(count) > spin_unlock(wait_lock) > schedule()
