futex: Add mutex around futex exit

The mutex will be used in subsequent changes to replace the busy looping of
a waiter when the futex owner is currently executing the exit cleanup to
prevent a potential live lock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.845798895@linutronix.de
This commit is contained in:
Thomas Gleixner 2019-11-06 22:55:44 +01:00
parent af8cbda2cf
commit 3f186d9748
3 changed files with 18 additions and 0 deletions

View file

@ -65,6 +65,7 @@ static inline void futex_init_task(struct task_struct *tsk)
INIT_LIST_HEAD(&tsk->pi_state_list);
tsk->pi_state_cache = NULL;
tsk->futex_state = FUTEX_STATE_OK;
mutex_init(&tsk->futex_exit_mutex);
}
void futex_exit_recursive(struct task_struct *tsk);