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Subject: Re: [CRAZY-RFF] debugfs: track open files and release on remove
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, nstange@suse.de, ap420073@gmail.com,
        David.Laight@aculab.com, netdev@vger.kernel.org,
        linux-wireless@vger.kernel.org, rafael@kernel.org
Date:   Fri, 09 Oct 2020 10:48:09 +0200
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On Fri, 2020-10-09 at 10:47 +0200, Greg KH wrote:

> > I think adding the .owner everywhere would be good, and perhaps we can
> > somehow put a check somewhere like
> > 
> > 	WARN_ON(is_module_address((unsigned long)fops) && !fops->owner);
> > 
> > to prevent the issue in the future?
> 
> That will fail for all of the debugfs_create_* operations, as there is
> only one set of file operations for all of the different files created
> with these calls.

Why would it fail? Those have their fops in the core debugfs code, which
might have a .owner assigned but is probably built-in anyway?

> Which, now that I remember it, is why we went down the proxy "solution"
> in the first place :(

Not sure I understand. That was related more to (arbitrary) files having
to be disappeared rather than anything else?

johannes