wake_up(pipe->wr_wait) makes no sense if pipe_full() is still true after the reading, the writer sleeping in wait_event(wr_wait, pipe_writable()) will check the pipe_writable() == !pipe_full() condition and sleep again. Only wake the writer if we actually released a pipe buf, and the pipe was full before we did so. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Link: https://lore.kernel.org/all/20241229135737.GA3293@redhat.com/ Link: https://lore.kernel.org/r/20250102140715.GA7091@redhat.com Reported-by: WangYuli <wangyuli@uniontech.com> Signed-off-by: Christian Brauner <brauner@kernel.org>