linux-kernel - Re: [RFC] Input: Remove unsafe device module references

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Message-ID: <CANq1E4T6urGVLC7xEa_4D=sCGYD0zsiVbH9u_E6O_xwuhR2Z4g@mail.gmail.com>
Date:	Tue, 1 Nov 2011 19:09:27 +0100
From:	David Herrmann <dh.herrmann@...glemail.com>
To:	Greg KH <gregkh@...e.de>
Cc:	linux-input@...r.kernel.org, dmitry.torokhov@...il.com,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC] Input: Remove unsafe device module references

On Tue, Nov 1, 2011 at 7:00 PM, Greg KH <gregkh@...e.de> wrote:
> On Tue, Nov 01, 2011 at 06:52:11PM +0100, David Herrmann wrote:
>> My solution: Some parent subsystem of us must take and release this
>> module-refcnt instead of us, so this bug doesn't occur.
>
> Yes, that is the ultimate solution for something like this.
>
> But, in reality, we don't care about module unloading races as there are
> plenty of other issues involved there where things can go bad, so we
> just try the best we can :)

Ah, I am kind of relieved that I got this right. I almost started
thinking I am insane.. ;)

So your answer is that this is so unlikely that it won't be fixed? I
am fine with that, even though I wonder why stuff like "struct
file_operations" include "owner" fields to protect callbacks but
"struct device_type" does *not* include any protection of it's
"release" callback.
This is why I thought calling module_get/put() inside the driver-core
would be just consistent with other subsystems.

But if this race is fine, I will simply copy it.

> thanks,
>
> greg k-h

Sorry for the confusion and thanks for your answers.
Regards
David
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