| Date | Tue, 7 Mar 2017 14:26:37 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH -v5 09/14] futex: Rework inconsistent rt_mutex/futex_q state |
| |
On Sat, 4 Mar 2017, Peter Zijlstra wrote: > @@ -1402,12 +1402,18 @@ static int wake_futex_pi(u32 __user *uad > new_owner = rt_mutex_next_owner(&pi_state->pi_mutex); > > /* > - * It is possible that the next waiter (the one that brought > - * top_waiter owner to the kernel) timed out and is no longer > - * waiting on the lock. > + * When we interleave with futex_lock_pi() where it does > + * rt_mutex_timed_futex_lock(), we might observe @this futex_q waiter, > + * but the rt_mutex's wait_list can be empty (either still, or again, > + * depending on which side we land). > + * > + * When this happens, give up our locks and try again, giving the > + * futex_lock_pi() instance time to complete and unqueue_me().
time to complete, either by waiting on the rtmutex or removing itself from the futex queue.
Or something like that.
Thanks,
tglx
|