From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162296AbaDCGK5 (ORCPT ); Thu, 3 Apr 2014 02:10:57 -0400 Received: from cantor2.suse.de ([195.135.220.15]:55534 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964791AbaDCGKy (ORCPT ); Thu, 3 Apr 2014 02:10:54 -0400 Date: Thu, 03 Apr 2014 08:10:52 +0200 Message-ID: From: Takashi Iwai To: Jiri Slaby Cc: Samo Pogacnik , Jean Delvare , Arnd Bergmann , Greg Kroah-Hartman , Struan Bartlett , Andreas Schwab , gnomes@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] ttyprintk: Fix wrong tty_unregister_driver() call in the error path In-Reply-To: <1396441473.10789.23.camel@chaos.site> References: <1396434582-30799-1-git-send-email-tiwai@suse.de> <1396441473.10789.23.camel@chaos.site> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At Wed, 02 Apr 2014 14:24:33 +0200, Jean Delvare wrote: > > Le Wednesday 02 April 2014 à 12:29 +0200, Takashi Iwai a écrit : > > ttyprintk driver calls tty_unregister_driver() wrongly in the error > > path of tty_register_driver(). Also, setting ttyprintk_driver to NULL > > is utterly superfluous, so let's get rid of it, too. > > > > Reported-by: Jean Delvare > > Signed-off-by: Takashi Iwai > > --- > > drivers/char/ttyprintk.c | 2 -- > > 1 file changed, 2 deletions(-) > > > > diff --git a/drivers/char/ttyprintk.c b/drivers/char/ttyprintk.c > > index daea84c41743..2a39c5790364 100644 > > --- a/drivers/char/ttyprintk.c > > +++ b/drivers/char/ttyprintk.c > > @@ -210,10 +210,8 @@ static int __init ttyprintk_init(void) > > return 0; > > > > error: > > - tty_unregister_driver(ttyprintk_driver); > > put_tty_driver(ttyprintk_driver); > > tty_port_destroy(&tpk_port.port); > > - ttyprintk_driver = NULL; > > return ret; > > } > > device_initcall(ttyprintk_init); > > Reviewed-by: Jean Delvare Meanwhile, I found that tty_unregister_driver() was added intentionally in the commit f06fb543c1d0, TTY: ttyprintk, unregister tty driver on failure When the tty_printk driver fails to create a node in sysfs, the system crashes. It is because the driver registers a tty driver and frees it without deregistering it first. The fix is easy: add a call to tty_unregister_driver to the fail path. But, I failed to see why this is needed in the current code. Jiri, is your fix still valid at all? thanks, Takashi