Re: Lots of bugs with current->state = TASK_*INTERRUPTIBLE

Julia Lawall
2010-01-21T10:47:41Z

What about something like the following (drivers/macintosh/adb.c):

add_wait_queue(&state->wait_queue, &wait);
current->state = TASK_INTERRUPTIBLE;

for (;;) {
req = state->completed;
if (req != NULL)
state->completed = req->next;
else if (atomic_read(&state->n_pending) = 0)
ret = -EIO;
if (req != NULL || ret != 0)
break;

if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
spin_unlock_irqrestore(&state->lock, flags);
schedule();
spin_lock_irqsave(&state->lock, flags);
}

current->state = TASK_RUNNING;
remove_wait_queue(&state->wait_queue, &wait);

There is a call to schedule eventually after the first current->state
assignment, but it is not right after.

thanks,
julia