woken++;
tsk = waiter->task;
- wake_q_add(wake_q, tsk);
+ get_task_struct(tsk);
list_del(&waiter->list);
/*
- * Ensure that the last operation is setting the reader
+ * Ensure calling get_task_struct() before setting the reader
* waiter to nil such that rwsem_down_read_failed() cannot
* race with do_exit() by always holding a reference count
* to the task to wakeup.
*/
smp_store_release(&waiter->task, NULL);
+ /*
+ * Ensure issuing the wakeup (either by us or someone else)
+ * after setting the reader waiter to nil.
+ */
+ wake_q_add_safe(wake_q, tsk);
}
adjustment = woken * RWSEM_ACTIVE_READ_BIAS - adjustment;