On Thu, Sep 15, 2016 at 11:41:25AM -0700, Andy Lutomirski wrote: > I also wouldn't mind trying to do something to prevent ever dumping > the stack of an actively running task. It's definitely safe to dump: > > - current > > - any task that's stopped via ptrace, etc > > - any task on the current CPU if running atomically enough that the > task can't migrate (which probably covers the nasty NMI cases, I hope) > > What's *not* safe AFAIK is /proc/PID/stack. I don't know if we can > somehow fix that short of actually sending an interrupt or NMI to > freeze the task if it's running. I'm also not sure it's worth > worrying about it. Yeah, I proposed a fix for /proc/PID/stack a while back: https://lkml.kernel.org/r/cover.1424109806.git.jpoimboe@xxxxxxxxxx My idea was to use task_rq_lock() to lock the runqueue and then check tsk->on_cpu. I think Peter wasn't too keen on it. We'll need something similar for the livepatch consistency model. -- Josh -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
