linux-kernel - Re: [PATCH RESEND] kthread, tracing: Don't expose half-written comm when creating kthreads

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Message-ID: <20180723113741.66df3b50@gandalf.local.home>
Date:   Mon, 23 Jul 2018 11:37:41 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Snild Dolkow <snild@...y.com>
Cc:     <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...nel.org>,
        Jens Axboe <axboe@...nel.dk>, Tejun Heo <tj@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Enderborg <peter.enderborg@...y.com>,
        Yoshitaka Seto <yoshitaka.seto@...y.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>,
        KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
        John Stultz <john.stultz@...aro.org>
Subject: Re: [PATCH RESEND] kthread, tracing: Don't expose half-written comm
 when creating kthreads

On Mon, 23 Jul 2018 16:23:09 +0200
Snild Dolkow <snild@...y.com> wrote:

> On 07/23/2018 03:55 PM, Steven Rostedt wrote:
> 
> > Can you add a comment here stating something to the affect of:
> > 		/* task is now visible to other tasks */
> >
> > -- Steve  
> Sure, but isn't that a bit misleading? It will have been visible since
> some unknown point in time between waking up kthreadd and the return of
> wait_for_completion(); we're not the ones making it visible.
> 

I guess that should be reworded, as that is not what I meant, and I
thought not what I stated. It's stating that the task is now visible,
not that we are now making it invisible. But I guess I was being too
short with what I meant. Here's the full statement:

		/*
		 * task is now visible by other tasks, so updating COMM
		 * must be protected.
		 */

-- Steve