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From: Dmitry Antipov <dmitry.antipov@linaro.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Module/kthread/printk question/problem
Date: Thu, 02 Feb 2012 13:20:18 +0400	[thread overview]
Message-ID: <4F2A5552.70302@linaro.org> (raw)
In-Reply-To: <1328168701.2902.14.camel@edumazet-laptop>

On 02/02/2012 11:45 AM, Eric Dumazet wrote:

> Remove the wait_for_completion(), this brings nothing at all, as you
> already discovered.

I want to get the module 'locked' until all threads are completed.

> Then you need cooperation from worker threads : they must wait for
> kthread_should_stop(), or else your kthread_stop(arg) pass an already
> freed "arg" memory block.

I designed the cooperation in another way: after each successful call
of X = kthread_run(...), I do get_task_struct(X), and the module exit
code is something like:

...
wait_for_completion(&done);
for (i = 0; i < nrthreads; i++) {
	kthread_stop(threads[i]);
	put_task_struct(threads[i]);
}
kfree(threads);
...

The crash is go away, so I believe this is reasonable. Anyway, it would
be nice to have a debug option to detect such a suspicious errors.

Thanks,
Dmitry

  reply	other threads:[~2012-02-02  9:20 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-01 16:09 Module/kthread/printk question/problem Dmitry Antipov
2012-02-01 16:31 ` Eric Dumazet
2012-02-01 16:35   ` Dmitry Antipov
2012-02-01 17:16     ` Eric Dumazet
2012-02-02  6:13       ` Dmitry Antipov
2012-02-02  7:45         ` Eric Dumazet
2012-02-02  9:20           ` Dmitry Antipov [this message]
2012-02-02  9:15         ` Eric Dumazet
2012-02-02  9:22           ` Dmitry Antipov
2012-02-02  9:58             ` Eric Dumazet
2012-02-06 23:43               ` Rusty Russell

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