diff options
Diffstat (limited to 'drivers/android/binder.c')
| -rw-r--r-- | drivers/android/binder.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 87ab35bae6b0..1fe8ab0144c6 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -4473,8 +4473,29 @@ static int binder_thread_release(struct binder_proc *proc, if (t) spin_lock(&t->lock); } + + /* + * If this thread used poll, make sure we remove the waitqueue + * from any epoll data structures holding it with POLLFREE. + * waitqueue_active() is safe to use here because we're holding + * the inner lock. + */ + if ((thread->looper & BINDER_LOOPER_STATE_POLL) && + waitqueue_active(&thread->wait)) { + wake_up_poll(&thread->wait, POLLHUP | POLLFREE); + } + binder_inner_proc_unlock(thread->proc); + /* + * This is needed to avoid races between wake_up_poll() above and + * and ep_remove_waitqueue() called for other reasons (eg the epoll file + * descriptor being closed); ep_remove_waitqueue() holds an RCU read + * lock, so we can be sure it's done after calling synchronize_rcu(). + */ + if (thread->looper & BINDER_LOOPER_STATE_POLL) + synchronize_rcu(); + if (send_reply) binder_send_failed_reply(send_reply, BR_DEAD_REPLY); binder_release_work(proc, &thread->todo); @@ -4490,6 +4511,8 @@ static unsigned int binder_poll(struct file *filp, bool wait_for_proc_work; thread = binder_get_thread(proc); + if (!thread) + return POLLERR; binder_inner_proc_lock(thread->proc); thread->looper |= BINDER_LOOPER_STATE_POLL; |