Re: [RFC] hung task: check specific tasks for long uninterruptible sleep state

[Andrew Morton]

On Wed, 8 Nov 2017 20:57:42 +0900 Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote:

> Lingutla Chandrasekhar wrote:
> > Some tasks may intentionally moves to uninterruptable sleep state,
> > which shouldn't leads to khungtask panics, as those are recoverable
> > hungs. So to avoid false hung reports, add an option to select tasks
> > to be monitored and report/panic them only.
> 
> What are backtraces of such tasks? Please point the locations in the code.
> 
> If they are absolutely recoverable, why can't we let themselves declare that
> "I'm intentionally in uninterruptible state. But there is no dependency that
> prevents me from recovering. So, please ignore me." using per "struct
> task_struct" flags rather than introducing userspace controlled interface?

Yes.  Please tell us much much much more about the use case and
scenarios which inspired this change.