On 3/18/19 4:19 PM, James Bottomley wrote: >> @@ -203,12 +203,14 @@ __poll_t tpm_common_poll(struct file *file, >> poll_table *wait) >> __poll_t mask = 0; >> >> poll_wait(file, &priv->async_wait, wait); >> + mutex_lock(&priv->buffer_mutex); >> >> if (!priv->response_read || priv->response_length) >> mask = EPOLLIN | EPOLLRDNORM; >> else >> mask = EPOLLOUT | EPOLLWRNORM; >> >> + mutex_unlock(&priv->buffer_mutex); > This doesn't do anything to address the theory that the queued work > hasn't run before the poll wakes up, does it? If you have an > alternative theory, could you explain it?
Right, it needs to be guarded by the mutex and also the condition should only check priv->response_length, because we only care about if there is data to read. The response_read flag only prevents double writes, without reading in the middle (or a timeout) which clean it. I will send a v2 soon. Thanks, -- Tadeusz
