To prevent races with ep_remove_waitqueue() removing the waitqueue at the same time. Reported-by: syzbot+a2a3c4909716e271487e@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Martijn Coenen <maco@xxxxxxxxxxx> --- drivers/android/binder.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 15e3d3c2260d..359220f87e1d 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -4376,6 +4376,15 @@ static int binder_thread_release(struct binder_proc *proc, 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); -- 2.16.1.291.g4437f3f132-goog _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
