linux-kernel - Re: [PATCH v2 1/3] firmware loader: Introduce new API

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20141119020502.GC6054@kroah.com>
Date:	Tue, 18 Nov 2014 18:05:02 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	"Kweh, Hock Leong" <hock.leong.kweh@...el.com>
Cc:	Matt Fleming <matt@...sole-pimps.org>,
	Ming Lei <ming.lei@...onical.com>,
	"Fleming, Matt" <matt.fleming@...el.com>,
	Sam Protsenko <semen.protsenko@...aro.org>,
	Henrique de Moraes Holschuh <hmh@....eng.br>,
	LKML <linux-kernel@...r.kernel.org>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"Ong, Boon Leong" <boon.leong.ong@...el.com>
Subject: Re: [PATCH v2 1/3] firmware loader: Introduce new API -
 request_firmware_abort()

On Tue, Nov 18, 2014 at 06:31:38AM +0000, Kweh, Hock Leong wrote:
> > -----Original Message-----
> > From: Matt Fleming [mailto:matt@...sole-pimps.org]
> > Sent: Monday, November 17, 2014 11:12 PM
> > >
> > > - Only doing module unload is required to be aware of this synchronization
> > > 	-> Ensuring the call back does not fall into unloaded code which may
> > cause
> > > 	     undefined behavior.
> > > 	-> Ensuring the put_device() & module_put() code have finished in
> > firmware_class.c
> > > 	     function request_firmware_work_func() before the device is
> > unregistered
> > > 	     and module unloaded happen.
> > 
> > Shouldn't the existing module_{put,get}() and {put,get}_device() calls
> > provide all the necessary synchronisation?
> > 
> > Module unload should not be possible while other code is using the
> > module (and the module refcnt has been incremented accordindly).
> > 
> > Right?
> > 
> > --
> > Matt Fleming, Intel Open Source Technology Center
> 
> Hi Matt,
> 
> Yes, you are right. If the module refcount is not zero, you will get error
> message and returned while you do "rmmod". But I strongly believe if we
> have the capability in our code to take care of it by doing synchronization,
> we should take care of it in case people are doing "rmmod -f". Don't
> you think so?

If you do 'rmmod -f' you get to keep all of the broken pieces of your
kernel, no need to try to help out with crazy things like that.

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/