Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755170Ab0AETAw (ORCPT ); Tue, 5 Jan 2010 14:00:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754739Ab0AETAs (ORCPT ); Tue, 5 Jan 2010 14:00:48 -0500 Received: from mail-fx0-f225.google.com ([209.85.220.225]:59982 "EHLO mail-fx0-f225.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754732Ab0AETAr (ORCPT ); Tue, 5 Jan 2010 14:00:47 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:subject:date:user-agent:cc:references:in-reply-to :mime-version:message-id:content-type:content-transfer-encoding; b=xOlNBjYfY3KC70CSZGSC8BA3WK8nmXW8ng1kKF2CP1lsLpsSylEkFwJA7eO1lx0skZ L5T2KaEfoiLBC+dMO5jp3we7KS81A5yX/BoP19Y9pTD1D214oXugCGtWecrRuoThDcg4 EXlkua5sKG06Ns9AAOt4Fc1a2+TASRF7Q7kgo= From: Bartlomiej Zolnierkiewicz To: Dmitry Torokhov Subject: Re: [PATCH] fujitsu-laptop: driver [un]registration fixes Date: Tue, 5 Jan 2010 17:46:46 +0100 User-Agent: KMail/1.12.2 (Linux/2.6.31.8-0.1-desktop; KDE/4.3.1; x86_64; ; ) Cc: Jonathan Woithe , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org References: <200912212232.nBLMWe5r016214@turbo.physics.adelaide.edu.au> <200912211446.32380.dmitry.torokhov@gmail.com> In-Reply-To: <200912211446.32380.dmitry.torokhov@gmail.com> MIME-Version: 1.0 Message-Id: <201001051746.46942.bzolnier@gmail.com> Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3477 Lines: 110 Hi, On Monday 21 December 2009 11:46:32 pm Dmitry Torokhov wrote: > Hi Jonathan, > > On Monday 21 December 2009 02:32:40 pm Jonathan Woithe wrote: > > Hi Dmitry > > > > > On Wed, Jul 29, 2009 at 10:15:33PM +0200, Bartlomiej Zolnierkiewicz wrote: > > > > @@ -722,22 +722,22 @@ static int acpi_fujitsu_add(struct acpi_ > > > > > > > > return result; > > > > > > > > -end: > > > > +err_unregister_input_dev: > > > > + input_unregister_device(input); > > > > err_free_input_dev: > > > > input_free_device(input); > > > > err_stop: > > > > > > Just noticed it scanning ACPI list. You must not use input_free_device() > > > after calling input_unregister_device() since unregister likely drops the > > > last reference to the device and it will get freed by input core. > > > > So what's the correct way to deal with that in this case? Something like > > > > -end: > > +err_unregister_input_dev: > > + input_unregister_device(input); > > + goto err_stop; > > err_free_input_dev: > > input_free_device(input); > > err_stop: > > > > (with a short comment to explain the goto) would circumvent the problem but > > it looks ugly (at least to my eyes - I've never really liked "goto"s :-) ). > > Just do "input = NULL;" after calling input_unregister_device() - > input_free_device() is like kfree() and will happily ignore passed NULL > pointers. > > Or rearrange the code to register device last, when everything is ready. I don't see it fixed in Linus' tree or linux-next yet so here is a patch: (thanks for noticing the issue and sorry for the delayed reply). [ Jonathan, please apply. Thanks! ] From: Bartlomiej Zolnierkiewicz Subject: [PATCH] fujitsu-laptop: fix input_free_device() usage input_free_device() must not be used after calling input_unregister_device() since unregister likely drops the last reference to the device and it will get freed by input core. Fix all input_unregister_device()+input_free_device() occurences accordingly. Noticed-by: Dmitry Torokhov Signed-off-by: Bartlomiej Zolnierkiewicz --- against current Linus' tree drivers/platform/x86/fujitsu-laptop.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) Index: b/drivers/platform/x86/fujitsu-laptop.c =================================================================== --- a/drivers/platform/x86/fujitsu-laptop.c +++ b/drivers/platform/x86/fujitsu-laptop.c @@ -724,6 +724,7 @@ static int acpi_fujitsu_add(struct acpi_ err_unregister_input_dev: input_unregister_device(input); + input = NULL; err_free_input_dev: input_free_device(input); err_stop: @@ -737,8 +738,6 @@ static int acpi_fujitsu_remove(struct ac input_unregister_device(input); - input_free_device(input); - fujitsu->acpi_handle = NULL; return 0; @@ -929,6 +928,7 @@ static int acpi_fujitsu_hotkey_add(struc err_unregister_input_dev: input_unregister_device(input); + input = NULL; err_free_input_dev: input_free_device(input); err_free_fifo: @@ -952,8 +952,6 @@ static int acpi_fujitsu_hotkey_remove(st input_unregister_device(input); - input_free_device(input); - kfifo_free(&fujitsu_hotkey->fifo); fujitsu_hotkey->acpi_handle = NULL; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/