From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FEC5606A326 for ; Fri, 6 Nov 2026 13:33:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RB21rBPU Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C40D7112D6A; Fri, 6 Nov 2026 13:33:17 +0000 (UTC) Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7F663112D6A for ; Fri, 6 Nov 2026 13:33:11 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 53BCB40D41 for ; Fri, 6 Nov 2026 13:33:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1950C1F0089F; Fri, 6 Nov 2026 13:33:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793971991; bh=k6iVkbOfucje5xhfpTi5BED914rn6xsYJ9XmJAWbNck=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=RB21rBPUhkc36kBmJoC8IPxkOS8sdyfvEwAt7kykAGK5rDcXxFdUWji7UGDlGfjuh 9X9qCHX0mEfTIfzce4MWVh51f7HS0ooojm6nLz5WScCU3pCMFyQ07UUKAkuE/Wre04 sH4NPYITWYNyC06e0whr0SAuIgi6zhmXVrKfrMek77wOyHkZ8R7ESnDfpO+RkMtybE QdVltLxhlF7vboNuzqxU+8Cx0jBXLxgNiAAoeZrLaixLwM+5dz7aqqAUQoCXV2JFWF YsMk7EYllDWHLpVycPMGKUlB5LUfopbryjldEHsZ4xmtWfza1PD2TAJHz9VENxTNY8 Yx0+a7resrZ3A== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v8 01/39] drm/ingenic: Convert to devm_drm_bridge_alloc() To: "Maxime Ripard" Cc: dri-devel@lists.freedesktop.org In-Reply-To: <20261106-drm-state-readout-v8-1-cbe78624e1bc@kernel.org> References: <20261106-drm-state-readout-v8-0-cbe78624e1bc@kernel.org> <20261106-drm-state-readout-v8-1-cbe78624e1bc@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 06 Nov 2026 13:33:10 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "dri-devel" X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 2 potential issues to consider: - [High] drm/ingenic: use-after-free in ingenic_drm_bind() from devm/drmm mismatch - [Low] drm/ingenic: missing devm_drm_bridge_add() in ingenic_drm_bind() -- commit b0cc78f8ec81445f2abbfeb18a785a51d40b8824 Author: Maxime Ripard drm/ingenic: Convert to devm_drm_bridge_alloc() This commit converts struct ingenic_drm_bridge allocation in ingenic_drm_bind() from drmm_encoder_alloc() to devm_drm_bridge_alloc() paired with drmm_encoder_init(). > diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/= ingenic/ingenic-drm-drv.c > index 63198fd594984..8cad8dcfae609 100644 > --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c > +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c > @@ -1303,20 +1303,27 @@ static int ingenic_drm_bind(struct device *dev, b= ool has_components) > drm_panel_put(panel); > } > =20 > - ib =3D drmm_encoder_alloc(drm, struct ingenic_drm_bridge, encoder, > - NULL, DRM_MODE_ENCODER_DPI, NULL); > + ib =3D devm_drm_bridge_alloc(dev, struct ingenic_drm_bridge, > + bridge, &ingenic_drm_bridge_funcs); > if (IS_ERR(ib)) { > ret =3D PTR_ERR(ib); > - dev_err(dev, "Failed to init encoder: %d\n", ret); > + dev_err(dev, "Failed to allocate bridge: %d\n", ret); > goto err_drvdata; > } > =20 > encoder =3D &ib->encoder; > + > + ret =3D drmm_encoder_init(drm, encoder, NULL, > + DRM_MODE_ENCODER_DPI, NULL); > + if (ret) { > + dev_err(dev, "Failed to init encoder: %d\n", ret); > + goto err_drvdata; > + } [Severity: High] Can mixing devm_drm_bridge_alloc() and drmm_encoder_init() on the same struct ingenic_drm_bridge cause a use-after-free of ib->encoder during teardown? ingenic_drm_bind() allocates drm via devm_drm_dev_alloc() before calling devm_drm_bridge_alloc(), so devres runs drm_bridge_put_void(&ib->bridge) before devm_drm_dev_init_release() runs drm_managed_release(). On unbind, drm_bridge_put_void() drops the devm reference on ib->bridge, leaving only the reference taken by drm_bridge_attach(). When drmm_encoder_alloc_release() then calls drm_encoder_cleanup(&ib->encoder), detaching ib->bridge drops its last reference and __drm_bridge_free() frees the entire struct ingenic_drm_bridge container while drm_encoder_cleanup() is still accessing encoder: drivers/gpu/drm/drm_encoder.c:drm_encoder_cleanup() { ... list_for_each_entry_safe(bridge, next, &tmplist, chain_node) drm_bridge_detach(bridge); drm_mode_object_unregister(dev, &encoder->base); kfree(encoder->name); list_del(&encoder->head); dev->mode_config.num_encoder--; mutex_destroy(&encoder->bridge_chain_mutex); memset(encoder, 0, sizeof(*encoder)); } If drm_bridge_attach() fails earlier during bind (for example with -EPROBE_DEFER), drm_bridge_put_void() frees ib before drm_managed_release() even enters drm_encoder_cleanup(). > + > encoder->possible_crtcs =3D drm_crtc_mask(&priv->crtc); > =20 > drm_encoder_helper_add(encoder, &ingenic_drm_encoder_helper_funcs); > =20 > - ib->bridge.funcs =3D &ingenic_drm_bridge_funcs; > ib->next_bridge =3D bridge; > =20 > ret =3D drm_bridge_attach(encoder, &ib->bridge, NULL, [Severity: Low] Does attaching &ib->bridge without calling devm_drm_bridge_add() first trigger a warning in drm_bridge_attach()? Previously drmm_encoder_alloc() zero-initialized ib->bridge.list, so list_empty(&bridge->list) was false. __devm_drm_bridge_alloc() initializes bridge->list with INIT_LIST_HEAD(), causing drm_bridge_attach() to hit DRM_WARN("Missing drm_bridge_add() before attach\n") on every probe. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261106-drm-state-= readout-v8-0-cbe78624e1bc@kernel.org?part=3D1