From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25B4EC2D0C3 for ; Mon, 30 Dec 2019 07:11:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDAAE20718 for ; Mon, 30 Dec 2019 07:11:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727190AbfL3HLd (ORCPT ); Mon, 30 Dec 2019 02:11:33 -0500 Received: from mx2.suse.de ([195.135.220.15]:48178 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727136AbfL3HLd (ORCPT ); Mon, 30 Dec 2019 02:11:33 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 8B7B9B26D; Mon, 30 Dec 2019 07:11:30 +0000 (UTC) Date: Mon, 30 Dec 2019 08:11:30 +0100 Message-ID: From: Takashi Iwai To: Dmitry Osipenko Cc: Thierry Reding , Jonathan Hunter , Mark Brown , Jaroslav Kysela , Bard Liao , Oder Chiou , Liam Girdwood , Takashi Iwai , linux-tegra@vger.kernel.org, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] ASoC: rt5640: Fix NULL dereference on module unload In-Reply-To: <20191229150454.2127-1-digetx@gmail.com> References: <20191229150454.2127-1-digetx@gmail.com> 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/25.3 (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=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 29 Dec 2019 16:04:54 +0100, Dmitry Osipenko wrote: > > The rt5640->jack is NULL if jack is already disabled at the time of > driver's module unloading. > > Unable to handle kernel NULL pointer dereference at virtual address 00000024 > ... > (rt5640_set_jack [snd_soc_rt5640]) from [] (snd_soc_component_set_jack+0x11/0x1c [snd_soc_core]) > (snd_soc_component_set_jack [snd_soc_core]) from [] (soc_remove_component+0x1b/0x54 [snd_soc_core]) > (soc_remove_component [snd_soc_core]) from [] (soc_cleanup_card_resources+0xad/0x1cc [snd_soc_core]) > (soc_cleanup_card_resources [snd_soc_core]) from [] (snd_soc_unregister_card+0x47/0x78 [snd_soc_core]) > (snd_soc_unregister_card [snd_soc_core]) from [] (tegra_rt5640_remove+0x13/0x1c [snd_soc_tegra_rt5640]) > (tegra_rt5640_remove [snd_soc_tegra_rt5640]) from [] (platform_drv_remove+0x17/0x24) > (platform_drv_remove) from [] (device_release_driver_internal+0x95/0x114) > (device_release_driver_internal) from [] (driver_detach+0x4d/0x90) > (driver_detach) from [] (bus_remove_driver+0x31/0x70) > (bus_remove_driver) from [] (tegra_rt5640_driver_exit+0x9/0xdf4 [snd_soc_tegra_rt5640]) > (tegra_rt5640_driver_exit [snd_soc_tegra_rt5640]) from [] (sys_delete_module+0xe7/0x184) > (sys_delete_module) from [] (ret_fast_syscall+0x1/0x28) > > Signed-off-by: Dmitry Osipenko > --- > sound/soc/codecs/rt5640.c | 22 ++++++++++++++-------- > 1 file changed, 14 insertions(+), 8 deletions(-) > > diff --git a/sound/soc/codecs/rt5640.c b/sound/soc/codecs/rt5640.c > index adbae1f36a8a..b245c44cafbc 100644 > --- a/sound/soc/codecs/rt5640.c > +++ b/sound/soc/codecs/rt5640.c > @@ -2432,16 +2432,22 @@ static void rt5640_disable_jack_detect(struct snd_soc_component *component) > { > struct rt5640_priv *rt5640 = snd_soc_component_get_drvdata(component); > > - disable_irq(rt5640->irq); > - rt5640_cancel_work(rt5640); > + /* > + * soc_remove_component() force-disables jack and thus rt5640->jack > + * could be NULL at the time of driver's module unloading. > + */ > + if (rt5640->jack) { > + disable_irq(rt5640->irq); > + rt5640_cancel_work(rt5640); > > - if (rt5640->jack->status & SND_JACK_MICROPHONE) { > - rt5640_disable_micbias1_ovcd_irq(component); > - rt5640_disable_micbias1_for_ovcd(component); > - snd_soc_jack_report(rt5640->jack, 0, SND_JACK_BTN_0); > - } > + if (rt5640->jack->status & SND_JACK_MICROPHONE) { > + rt5640_disable_micbias1_ovcd_irq(component); > + rt5640_disable_micbias1_for_ovcd(component); > + snd_soc_jack_report(rt5640->jack, 0, SND_JACK_BTN_0); > + } > > - rt5640->jack = NULL; > + rt5640->jack = NULL; > + } > } I guess it's simpler just returning if rt5640->jack is already NULL. --- a/sound/soc/codecs/rt5640.c +++ b/sound/soc/codecs/rt5640.c @@ -2432,6 +2432,10 @@ static void rt5640_disable_jack_detect(struct snd_soc_component *component) { struct rt5640_priv *rt5640 = snd_soc_component_get_drvdata(component); + /* already disabled? */ + if (!rt5640->jack) + return; + disable_irq(rt5640->irq); rt5640_cancel_work(rt5640); thanks, Takashi