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

From: Miroslav Benes
Date: Fri Mar 26 2021 - 04:40:03 EST


On Thu, 25 Mar 2021, Jens Axboe wrote:

> On 3/25/21 3:30 AM, Miroslav Benes wrote:
> >> (PF_KTHREAD | PF_IO_WORKER) is open coded in soo many places maybe this is a
> >> silly question, but...
> >>
> >> If the livepatch code could use fake_signal_wake_up(), we could consolidate
> >> the pattern in klp_send_signals() with the one in freeze_task(). Then there
> >> would only one place for wake up / fake signal logic.
> >>
> >> I don't fully understand the differences in the freeze_task() version, so I
> >> only pose this as a question and not v2 request.
> >
> > The plan was to remove our live patching fake signal completely and use
> > the new infrastructure Jens proposed in the past.
>
> That would be great, I've actually been waiting for that to show up!

Sorry about that. I failed to notice that the infrastructure was merged
already. I'll send it soonish.

> I would greatly prefer this approach if you deem it suitable for 5.12,
> if not we'll still need the temporary work-around for live patching.

I noticed there is 20210326003928.978750-1-axboe@xxxxxxxxx now, so I
suppose we should wait for that to land in mainline and simply do nothing
about PF_IO_WORKER for live patching.

Miroslav