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From:   John Ogness <john.ogness@linutronix.de>
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To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
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        Joel Fernandes <joel@joelfernandes.org>,
        Kees Cook <keescook@chromium.org>,
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        Phil Auld <pauld@redhat.com>,
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        Wang Qing <wangqing@vivo.com>, rcu@vger.kernel.org
Subject: Re: [PATCH printk v2 00/12] implement threaded console printing
In-Reply-To: <YkxaTy08ClcNj0P3@smile.fi.intel.com>
References: <20220405132535.649171-1-john.ogness@linutronix.de>
 <YkxaTy08ClcNj0P3@smile.fi.intel.com>
Date:   Tue, 05 Apr 2022 23:30:10 +0206
Message-ID: <87sfqrrzph.fsf@jogness.linutronix.de>
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On 2022-04-05, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> From the list of patches and the only one I am Cc'ed to I can't find
> the answer to my question,

It seems lore is having trouble picking up the series. Until then, I've
pushed the series to github.com so you can see the code.

> i.e. does it take care about console_unregister() cases at run time?
> (We have some drivers to call ->exit() for console in that case,
> perhaps it should do something before calling it.)

Yes. In console_unregister(), the printing thread is shutdown before the
actual console unregistration takes place. The thread is shutdown here:

https://github.com/Linutronix/linux/blob/b27eb6c3d168d608b3a9d04578e030a3d79d889a/kernel/printk/printk.c#L3393

The console's exit() callback is below that:

https://github.com/Linutronix/linux/blob/b27eb6c3d168d608b3a9d04578e030a3d79d889a/kernel/printk/printk.c#L3429

> Would be nice to see some pointers where I can find the answer and
> maybe even describing in the cover-letter/commit
> message/documentation.

I suppose for the console thread patch [0] I could add a paragraph to
the commit message mentioning kernel thread shutdown for console
unregistration.

[0] https://github.com/Linutronix/linux/commit/e26ae677da2e339dd268c1f871b81e61e782393f

John