On Mon, Apr 29, 2019 at 10:02:45AM -0400, Joel Fernandes wrote: > On Sun, Apr 28, 2019 at 06:24:06PM +0200, Oleg Nesterov wrote: [snip] > > > > +{ > > > > + struct pid *pid; > > > > + > > > > + lockdep_assert_held(&tasklist_lock); > > > > + > > > > + pid = get_task_pid(task, PIDTYPE_PID); > > > > + wake_up_all(&pid->wait_pidfd); > > > > + put_pid(pid); > > > > Why get/put? > > Yes, pid_task() should do it. Will update it. Thanks! I spoke too soon. We need the task's pid of type PIDTYPE_PID. How else can we get it? This does an atomic_inc on the pid->count, so we need to put_pid() after we are done with it. Did I miss something? thanks, - Joel