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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8656ACD8C92 for ; Mon, 8 Jun 2026 16:17:54 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DAB8510F6BB; Mon, 8 Jun 2026 16:17:53 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="cizt5d1B"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6A03210F6B8 for ; Mon, 8 Jun 2026 16:17:52 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id B426B60098 for ; Mon, 8 Jun 2026 16:17:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 457211F00893; Mon, 8 Jun 2026 16:17:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780935471; bh=f74z5kEAoCqUWAxFAW/1z82VkQgVAAxgCpla7hvyEwc=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=cizt5d1Bz02/UNbUaMoRhawcBorAdS5lFgR9enwmk4MPe4OknOICtrUjV3VNrgcQf lbweJH63paEJ7yfKcNJ8EgpqHmPMZCwrRDulsW36AUouwX9j301VGqZBygoCA3+9LG mZzNIyS7Q33NrY1PrP4gaeA9FpJC0obrZV7kgcj8m4xFAf+8rQ4IWoEltNNKjk8M0B B6Vk86EH02YAefL5zDAiqScYZ4klZ6tXRXPK22MRKjCsclbVpulGf9xtL2AGqwHWg1 pM56D1Ac897BV9UEv8berAy1uaa67lcrLnAHsgbGHGuOsnZj6JnOn2I8TsYksVJnv/ 55dvlzsxBnMjQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 28/78] drm/bridge: panel: Switch to atomic_create_state To: "Maxime Ripard" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20260608-drm-no-more-bridge-reset-v2-28-0a91018bf886@kernel.org> References: <20260608-drm-no-more-bridge-reset-v2-28-0a91018bf886@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 08 Jun 2026 16:17:50 +0000 Message-Id: <20260608161751.457211F00893@smtp.kernel.org> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: Pre-existing issues: - [High] Calling drm_connector_cleanup() directly in panel_bridge_detach() = zeroes the connector structure while userspace references may still exist, = leading to a NULL pointer dereference. -- commit 0c93dfe69dc6bce062c0a90960ed927307c7202d Author: Maxime Ripard drm/bridge: panel: Switch to atomic_create_state This commit updates the panel bridge driver to use the atomic_create_state callback instead of the deprecated atomic_reset callback. It switches to the corresponding drm_atomic_helper_bridge_create_state() helper. > diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/pane= l.c > index 4978ec98a0828..62af499f1f5cc 100644 > --- a/drivers/gpu/drm/bridge/panel.c > +++ b/drivers/gpu/drm/bridge/panel.c [ ... ] > static void panel_bridge_detach(struct drm_bridge *bridge) > { > struct panel_bridge *panel_bridge =3D drm_bridge_to_panel_bridge(bridge= ); > struct drm_connector *connector =3D &panel_bridge->connector; > =20 > if (connector->dev) > drm_connector_cleanup(connector); [Severity: High] This isn't a bug introduced by this patch, but I noticed a pre-existing iss= ue in panel_bridge_detach() here. Calling drm_connector_cleanup() directly zeroes the connector structure whi= le userspace references may still exist. If userspace or another kernel thread still holds an active reference to th= is connector (refcount > 0), dropping the final reference later will invoke drm_connector_free(). Since drm_connector_cleanup() uses memset to zero the structure, connector->funcs becomes NULL. When drm_connector_free() attempts to call connector->funcs->destroy(connector), it will cause a fatal NULL pointer dereference. Can this connector cleanup be deferred until the final reference is dropped rather than cleaning it up synchronously during detach? [ ... ] > @@ -213,7 +213,7 @@ static const struct drm_bridge_funcs panel_bridge_bri= dge_funcs =3D { > .atomic_disable =3D panel_bridge_atomic_disable, > .atomic_post_disable =3D panel_bridge_atomic_post_disable, > .get_modes =3D panel_bridge_get_modes, > - .atomic_reset =3D drm_atomic_helper_bridge_reset, > + .atomic_create_state =3D drm_atomic_helper_bridge_create_state, > .atomic_duplicate_state =3D drm_atomic_helper_bridge_duplicate_state, > .atomic_destroy_state =3D drm_atomic_helper_bridge_destroy_state, > .atomic_get_input_bus_fmts =3D drm_atomic_helper_bridge_propagate_bus_f= mt, --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260608-drm-no-mor= e-bridge-reset-v2-0-0a91018bf886@kernel.org?part=3D28