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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 9881BECDE30 for ; Wed, 17 Oct 2018 12:00:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 551822150D for ; Wed, 17 Oct 2018 12:00:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=agner.ch header.i=@agner.ch header.b="jyQEkfYG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 551822150D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=agner.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727255AbeJQT4H (ORCPT ); Wed, 17 Oct 2018 15:56:07 -0400 Received: from mail.kmu-office.ch ([178.209.48.109]:42586 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727013AbeJQT4H (ORCPT ); Wed, 17 Oct 2018 15:56:07 -0400 Received: from webmail.kmu-office.ch (unknown [IPv6:2a02:418:6a02::a3]) by mail.kmu-office.ch (Postfix) with ESMTPSA id 3212B5C02D9; Wed, 17 Oct 2018 14:00:41 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=agner.ch; s=dkim; t=1539777641; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I5ksCOEh0djQz+iDwXNCex/lLzXC+lFDjwNyKXU/mzw=; b=jyQEkfYGeoVTgLb5MtNusjnfwrelri3G04viyeWtRu8hpeo0UbiarqDHcSmLq37SiKCUau QOd7Z5XLZwzr+Oc22odKKYmA/y871m7ZMhIkn6DqPMP2WrYEwh7FUQ2oKk6gNJfptoQv+X nCwuA57ZsS6dq7U/1WuQ6wUFNVK60Aw= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Wed, 17 Oct 2018 14:00:41 +0200 From: Stefan Agner To: p.zabel@pengutronix.de Cc: airlied@linux.ie, rmk+kernel@armlinux.org.uk, l.stach@pengutronix.de, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Revert "drm/imx: don't destroy mode objects manually on driver unbind" In-Reply-To: References: <20181016160923.2042-1-stefan@agner.ch> Message-ID: <66518fd4ba1fe77344d849a0b3949342@agner.ch> X-Sender: stefan@agner.ch User-Agent: Roundcube Webmail/1.3.7 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17.10.2018 13:25, Stefan Agner wrote: > On 16.10.2018 18:09, Stefan Agner wrote: >> This reverts commit 8e3b16e2117409625b89807de3912ff773aea354. >> >> Using the component framework requires all components to undo in >> ->unbind what ->bind does. Unfortunately that particular commit >> broke this rule. In particular, this is an issue if a single >> component during probe fails. In that case, component_bind_all() >> calls unbind on already succussfully bound components, and then >> frees memory allocated using devm. If one of those components >> registered e.g. an encoder with the framework then this leads to >> use after free situations. >> >> Revert the commit to ensure that all components properly undo >> what ->bind does. > > After Lucas comment mentioning HDMI unbind is not proper I looked > through all the unbind again. The other unbind functions need some > fixing too. I did not bother checking whether those were always broken > or just because things changed (the commit this is reverting was in > 2016).... Here is what I found: > >> >> Link: >> https://www.mail-archive.com/dri-devel@lists.freedesktop.org/msg233327.html >> Suggested-by: Russell King >> Signed-off-by: Stefan Agner >> --- >> drivers/gpu/drm/imx/imx-drm-core.c | 4 ++-- >> drivers/gpu/drm/imx/imx-ldb.c | 6 ++++++ >> drivers/gpu/drm/imx/imx-tve.c | 3 +++ >> drivers/gpu/drm/imx/parallel-display.c | 3 +++ >> 4 files changed, 14 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/imx/imx-drm-core.c >> b/drivers/gpu/drm/imx/imx-drm-core.c >> index 5ea0c82f9957..caa6061a98ba 100644 >> --- a/drivers/gpu/drm/imx/imx-drm-core.c >> +++ b/drivers/gpu/drm/imx/imx-drm-core.c >> @@ -305,11 +305,11 @@ static void imx_drm_unbind(struct device *dev) >> >> drm_fb_cma_fbdev_fini(drm); >> >> - drm_mode_config_cleanup(drm); >> - >> component_unbind_all(drm->dev, drm); >> dev_set_drvdata(dev, NULL); >> >> + drm_mode_config_cleanup(drm); >> + >> drm_dev_put(drm); >> } >> >> diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c >> index 3bd0f8a18e74..592aabc4a262 100644 >> --- a/drivers/gpu/drm/imx/imx-ldb.c >> +++ b/drivers/gpu/drm/imx/imx-ldb.c >> @@ -723,6 +723,12 @@ static void imx_ldb_unbind(struct device *dev, >> struct device *master, >> if (channel->panel) >> drm_panel_detach(channel->panel); >> >> + if (!channel->connector.funcs) >> + continue; >> + >> + channel->connector.funcs->destroy(&channel->connector); >> + channel->encoder.funcs->destroy(&channel->encoder); > > There can be an encoder and bridge, or an encoder and connector. All of > them should be properly cleaned up. > > So I guess this should look like this: > > if (channel->panel) > drm_panel_detach(channel->panel); > > if (channel->bridge) > drm_bridge_detach(channel->bridge); Actually, when a bridge is attached to an encoder, which is the case when unbind is getting called, then encoder cleanup takes care of drm_bridge_detach. > > if (channel->connector.funcs) > channel->connector.funcs->destroy(&channel->connector); > > if (channel->encoder.funcs) > channel->encoder.funcs->destroy(&channel->encoder); > > kfree(channel->edid); > i2c_put_adapter(channel->ddc); > > The last two functions following are only strictly necessary when > connector is initialized. But its safe to call them with null, so I > would just call them always. > > >> + >> kfree(channel->edid); >> i2c_put_adapter(channel->ddc); >> } >> diff --git a/drivers/gpu/drm/imx/imx-tve.c b/drivers/gpu/drm/imx/imx-tve.c >> index cffd3310240e..8d6e89ce1edb 100644 >> --- a/drivers/gpu/drm/imx/imx-tve.c >> +++ b/drivers/gpu/drm/imx/imx-tve.c >> @@ -673,6 +673,9 @@ static void imx_tve_unbind(struct device *dev, >> struct device *master, >> { >> struct imx_tve *tve = dev_get_drvdata(dev); >> >> + tve->connector.funcs->destroy(&tve->connector); >> + tve->encoder.funcs->destroy(&tve->encoder); >> + > > Cleanup of tve->ddc missing. > >> if (!IS_ERR(tve->dac_reg)) >> regulator_disable(tve->dac_reg); >> } >> diff --git a/drivers/gpu/drm/imx/parallel-display.c >> b/drivers/gpu/drm/imx/parallel-display.c >> index aefd04e18f93..6f11bffcde37 100644 >> --- a/drivers/gpu/drm/imx/parallel-display.c >> +++ b/drivers/gpu/drm/imx/parallel-display.c >> @@ -258,6 +258,9 @@ static void imx_pd_unbind(struct device *dev, >> struct device *master, >> if (imxpd->panel) >> drm_panel_detach(imxpd->panel); >> > > And in this case a bridge detach is missing. Same here. > > Will send a v2 with that addressed. Still valid. -- Stefan > > -- > Stefan > >> + imxpd->encoder.funcs->destroy(&imxpd->encoder); >> + imxpd->connector.funcs->destroy(&imxpd->connector); >> + >> kfree(imxpd->edid); >> }