Re: [PATCH] livepatch: klp_send_signal should treat PF_IO_WORKER like PF_KTHREAD

[Joe Lawrence]

On 3/25/21 5:26 AM, Miroslav Benes wrote:
> On Thu, 25 Mar 2021, Dong Kai wrote:
>
> > commit 15b2219facad ("kernel: freezer should treat PF_IO_WORKER like
> > PF_KTHREAD for freezing") is to fix the freezeing issue of IO threads
> > by making the freezer not send them fake signals.
> >
> > Here live patching consistency model call klp_send_signals to wake up
> > all tasks by send fake signal to all non-kthread which only check the
> > PF_KTHREAD flag, so it still send signal to io threads which may lead to
> > freezeing issue of io threads.
>
> I suppose this could happen, but it will also affect the live patching
> transition if the io threads do not react to signals.
>
> Are you able to reproduce it easily? I mean, is there a testcase I could
> use to take a closer look?
>   

If repro is only hypothetical at this point, perhaps we can artificially 
create it in selftests?  And useful to verify the future change you 
mentioned in your other reply?

-- Joe