Re: [PATCH v2 1/2] livepatch: Send a fake signal periodically

From: Jiri Kosina
Date: Wed Jan 16 2019 - 16:11:17 EST


On Tue, 15 Jan 2019, Miroslav Benes wrote:

> An administrator may send a fake signal to all remaining blocking tasks
> of a running transition by writing to
> /sys/kernel/livepatch/<patch>/signal attribute. Let's do it
> automatically after 15 seconds. The timeout is chosen deliberately. It
> gives the tasks enough time to transition themselves.
>
> Theoretically, sending it once should be more than enough. However,
> every task must get outside of a patched function to be successfully
> transitioned. It could prove not to be simple and resending could be
> helpful in that case.
>
> A new workqueue job could be a cleaner solution to achieve it, but it
> could also introduce deadlocks and cause more headaches with
> synchronization and cancelling.
>
> Signed-off-by: Miroslav Benes <mbenes@xxxxxxx>
[ ... snip ... ]
> @@ -400,6 +408,7 @@ void klp_try_complete_transition(void)
> */
> schedule_delayed_work(&klp_transition_work,
> round_jiffies_relative(HZ));
> +
> return;
> }

I somehow didn't like the newly added newline here :) so I've removed it,
and applied both patches to for-5.1/fake-signal.

Thanks,

--
Jiri Kosina
SUSE Labs