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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 49509C43381 for ; Mon, 18 Jan 2021 10:26:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C90022BE9 for ; Mon, 18 Jan 2021 10:26:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389144AbhARK0j (ORCPT ); Mon, 18 Jan 2021 05:26:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389181AbhARJou (ORCPT ); Mon, 18 Jan 2021 04:44:50 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAFF3C061575; Mon, 18 Jan 2021 01:44:07 -0800 (PST) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 3A5D2AF0; Mon, 18 Jan 2021 10:44:06 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1610963046; bh=u/RGNnTWYJkbFYhanUxjfVEHJfSz/1T8zo9agvGtStE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XlfpbthhtUr1NTmAtFPFZ/OAla0Ej7qPB5RDBO8m8YRHC873pDiRXuT/Ik0DRHR1a I985M5iCiBG+bFLuwNRNOfl8b1m6MJC0HvD+JqoHhxPoNF3ILBwUzOfdg7j06n3w0S Z6817DKfi58aoQG1c47KA8EgsIRh5D+qkK2XqLRs= Date: Mon, 18 Jan 2021 11:43:50 +0200 From: Laurent Pinchart To: Paul Cercueil Cc: David Airlie , Daniel Vetter , Sam Ravnborg , od@zcrc.me, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Andrzej Hajda , Neil Armstrong , Jonas Karlman , Jernej Skrabec Subject: Re: [PATCH 1/3] drm: bridge/panel: Cleanup connector on bridge detach Message-ID: References: <20210117112646.98353-1-paul@crapouillou.net> <20210117112646.98353-2-paul@crapouillou.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210117112646.98353-2-paul@crapouillou.net> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hi Paul, Thank you for the patch. On Sun, Jan 17, 2021 at 11:26:44AM +0000, Paul Cercueil wrote: > If we don't call drm_connector_cleanup() manually in > panel_bridge_detach(), the connector will be cleaned up with the other > DRM objects in the call to drm_mode_config_cleanup(). However, since our > drm_connector is devm-allocated, by the time drm_mode_config_cleanup() > will be called, our connector will be long gone. Therefore, the > connector must be cleaned up when the bridge is detached to avoid > use-after-free conditions. > > Fixes: 13dfc0540a57 ("drm/bridge: Refactor out the panel wrapper from the lvds-encoder bridge.") > Cc: # 4.12+ > Cc: Andrzej Hajda > Cc: Neil Armstrong > Cc: Laurent Pinchart > Cc: Jonas Karlman > Cc: Jernej Skrabec > Signed-off-by: Paul Cercueil > --- > drivers/gpu/drm/bridge/panel.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c > index 0ddc37551194..975d65c14c9c 100644 > --- a/drivers/gpu/drm/bridge/panel.c > +++ b/drivers/gpu/drm/bridge/panel.c > @@ -87,6 +87,10 @@ static int panel_bridge_attach(struct drm_bridge *bridge, > > static void panel_bridge_detach(struct drm_bridge *bridge) > { > + struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge); > + struct drm_connector *connector = &panel_bridge->connector; > + > + drm_connector_cleanup(connector); The panel bridge driver only creates the connector if the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag wasn't set in panel_bridge_attach(). We shouldn't clean up the connector unconditionally. A better fix would be to stop using the devm_* API, but that's more complicated. > } > > static void panel_bridge_pre_enable(struct drm_bridge *bridge) -- Regards, Laurent Pinchart