linux-kernel - Re: [PATCH] modules, split MODULE_STATE

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: <20140930200642.GA27180@redhat.com>
Date:	Tue, 30 Sep 2014 22:06:42 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Prarit Bhargava <prarit@...hat.com>
Cc:	linux-kernel@...r.kernel.org,
	Rusty Russell <rusty@...tcorp.com.au>,
	Jason Wessel <jason.wessel@...driver.com>,
	Roland McGrath <roland@...k.frob.com>,
	kgdb-bugreport@...ts.sourceforge.net
Subject: Re: [PATCH] modules, split MODULE_STATE_UNFORMED into separate
	states

argh, sorry for noise,

On 09/30, Oleg Nesterov wrote:
>
> On 09/30, Prarit Bhargava wrote:
> >
> > MODULE_STATE_UNFORMED needs to be separated into two states; one for the
> > module load (MODULE_STATE_LOAD), and one for the module delete
> > (MODULE_STATE_DELETE).
> 
> And personally I think this makes sense in any case, but I can't really
> comment the changes in this area.
> 
> > @@ -3647,18 +3646,29 @@ static int m_show(struct seq_file *m, void *p)
> >  	struct module *mod = list_entry(p, struct module, list);
> >  	char buf[8];
> >  
> > -	/* We always ignore unformed modules. */
> > -	if (mod->state == MODULE_STATE_UNFORMED)
> > +	/*
> > +	 * If the state is MODULE_STATE_LOAD then the module is in
> > +	 * the early stages of loading.  No information should be printed
> > +	 * for this module as the data could be in an uninitialized state.
> > +	 */
> > +	if (mod->state == MODULE_STATE_LOAD)
> >  		return 0;
> 
> So this assumes that _UNFORMED state is fine...
                       ^^^^^^^^^
I meant MODULE_STATE_DELETE of course...

> Not sure, but I can be easily wrong. For example, print_unload_info() ->
> module_refcount() plays with mod->refptr, while free_module() does
> module_unload_free() -> free_percpu(mod->refptr). No?
> 
> Perhaps it makes sense to start with the simple patch for stable,
> 
> 	+	// sync with m_show()
> 	+	mutex_lock(module_mutex);
> 		mod->state = MODULE_STATE_UNFORMED;
> 	+	mutex_unlock(module_mutex);
> 
> then do a more sophisticated fix?
> 
> Oleg.

--
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/