linux-kernel - Re: [PATCH 2/3] livepatch: send a fake signal to all blocking tasks

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Message-ID: <20170523173021.scmqcpyk6qgnhywo@treble>
Date:   Tue, 23 May 2017 12:30:21 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Miroslav Benes <mbenes@...e.cz>
Cc:     jeyu@...hat.com, jikos@...nel.org, pmladek@...e.com,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
        Oleg Nesterov <oleg@...hat.com>
Subject: Re: [PATCH 2/3] livepatch: send a fake signal to all blocking tasks

On Thu, May 18, 2017 at 02:00:42PM +0200, Miroslav Benes wrote:
> @@ -551,3 +551,43 @@ void klp_copy_process(struct task_struct *child)
>  
>  	/* TIF_PATCH_PENDING gets copied in setup_thread_stack() */
>  }
> +
> +/*
> + * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set.
> + * Kthreads with TIF_PATCH_PENDING set are woken up. Only admin can request this
> + * action currently.
> + */
> +void klp_send_fake_signal(void)
> +{
> +	struct task_struct *g, *task;
> +
> +	pr_info("sending a fake signal and waking sleeping kthreads up\n");

Maybe this should be pr_notice(), for consistency with our other
printks.

Also I wonder if the message can be made more meaningful to the user.
The "fake" part of the signal and the "waking sleeping kthreads" bit
could be too much information for the user, IMO.  How about "signaling
remaining tasks"?  Just an idea.

-- 
Josh