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From: David Laight <David.Laight@ACULAB.COM>
To: 'Johannes Berg' <johannes@sipsolutions.net>,
	Greg KH <gregkh@linuxfoundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"nstange@suse.de" <nstange@suse.de>,
	"ap420073@gmail.com" <ap420073@gmail.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	"rafael@kernel.org" <rafael@kernel.org>
Subject: RE: [CRAZY-RFF] debugfs: track open files and release on remove
Date: Fri, 9 Oct 2020 09:00:41 +0000	[thread overview]
Message-ID: <e086db3e422b401d9a4df896696f75b8@AcuMS.aculab.com> (raw)
In-Reply-To: <e3a807b1d5f728c178f43b453f3b495bf53abfce.camel@sipsolutions.net>

From: Johannes Berg
> Sent: 09 October 2020 09:45
> 
> On Fri, 2020-10-09 at 08:34 +0000, David Laight wrote:
> >
...
> > Does it ever make any sense to set .owner to anything other than
> > THIS_MODULE?
> 
> No. But I believe THIS_MODULE is NULL for built-in code, so we can't
> just WARN_ON(!fops->owner).
...
> > I was also wondering if this affects normal opens?
> > They should hold a reference on the module to stop it being unloaded.
> > Does that rely on .owner being set?
> 
> Yes.

Sound like the module load code should be verifying it then.

Looking at one of my modules (which does set .owner).
Perhaps cdev_init() could be a #define that picks up THIS_MODULE.
This could then be checked against the one in fops or saved
in the 'struct cdev'.

I presume debugfs (which I've not used) has some similar calls.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  reply	other threads:[~2020-10-09  9:00 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <87v9fkgf4i.fsf@suse.de>
2020-10-09  7:53 ` Johannes Berg
2020-10-09  8:03   ` Greg KH
2020-10-09  8:06     ` Johannes Berg
2020-10-09  8:16       ` Greg KH
2020-10-09  8:19         ` Johannes Berg
2020-10-09  8:34           ` David Laight
2020-10-09  8:44             ` Johannes Berg
2020-10-09  9:00               ` David Laight [this message]
2020-10-09  8:47           ` Greg KH
2020-10-09  8:48             ` Johannes Berg
2020-10-10  9:38               ` Greg KH
2020-10-10 10:47                 ` Johannes Berg

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