Messages in this thread Patch in this message | | | Subject | Re: [tip:locking/core] rtmutex: Deboost before waking up the top waiter | From | Xunlei Pang <> | Date | Thu, 6 Apr 2017 14:16:15 +0800 |
| |
On 04/05/2017 at 04:08 PM, Mike Galbraith wrote: > locking/rtmutex: Fix preempt leak in __rt_mutex_futex_unlock() > > mark_wakeup_next_waiter() already disables preemption, doing so > again leaves us with an unpaired preempt_disable().
You can also fix the corresponding comment in rt_mutex_postunlock(): /* Pairs with preempt_disable() in rt_mutex_slowunlock() */ preempt_enable();
Thanks, Xunlei
> > Signed-off-by: Mike Galbraith <efault@gmx.de> > --- > kernel/locking/rtmutex.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > --- a/kernel/locking/rtmutex.c > +++ b/kernel/locking/rtmutex.c > @@ -1581,13 +1581,13 @@ bool __sched __rt_mutex_futex_unlock(str > return false; /* done */ > } > > - mark_wakeup_next_waiter(wake_q, lock); > /* > - * We've already deboosted, retain preempt_disabled when dropping > - * the wait_lock to avoid inversion until the wakeup. Matched > - * by rt_mutex_postunlock(); > + * We've already deboosted, mark_wakeup_next_waiter() will > + * retain preempt_disabled when we drop the wait_lock, to > + * avoid inversion prior to the wakeup. preempt_disable() > + * therein pairs with rt_mutex_postunlock(). > */ > - preempt_disable(); > + mark_wakeup_next_waiter(wake_q, lock); > > return true; /* call postunlock() */ > }
| |