From nobody Thu Sep 11 16:38:38 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F7DCC001DF for ; Fri, 4 Aug 2023 10:51:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229573AbjHDKvH (ORCPT ); Fri, 4 Aug 2023 06:51:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231600AbjHDKug (ORCPT ); Fri, 4 Aug 2023 06:50:36 -0400 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 8E98149E8 for ; Fri, 4 Aug 2023 03:48:36 -0700 (PDT) Received: from [127.0.1.1] (91-154-35-171.elisa-laajakaista.fi [91.154.35.171]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 4F8E5188E; Fri, 4 Aug 2023 12:47:25 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1691146046; bh=sSHNiN7SCW+dnAbLNBvXVtT0IFfFTc4U7kIWW6bzkcc=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=vqtielVZGZwDmNlYBA7mcOvKFUJXxaKDwV9ENxPhnF7RkoKUj+iyBdL5epoZglLE5 +VNMHB42QVM9YKyJhhogRZUWv63tw6wPo7fco2C2XFQ3G4Jn40mEUIz+J2IjEWB99Y H54EXzNb9GqIoivaraSX9uuHRfe0V6QhusyJ5mNM= From: Tomi Valkeinen Date: Fri, 04 Aug 2023 13:48:11 +0300 Subject: [PATCH 2/4] drm/bridge: lt8912b: Fix crash on bridge detach MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20230804-lt8912b-v1-2-c542692c6a2f@ideasonboard.com> References: <20230804-lt8912b-v1-0-c542692c6a2f@ideasonboard.com> In-Reply-To: <20230804-lt8912b-v1-0-c542692c6a2f@ideasonboard.com> To: Adrien Grassein , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , David Airlie , Daniel Vetter , Francesco Dolcini , Stefan Eichenberger Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Tomi Valkeinen X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=4076; i=tomi.valkeinen@ideasonboard.com; h=from:subject:message-id; bh=sSHNiN7SCW+dnAbLNBvXVtT0IFfFTc4U7kIWW6bzkcc=; b=owEBbQKS/ZANAwAIAfo9qoy8lh71AcsmYgBkzNd6zGvgxDYCLtrRiFJnpm3hEXSfsh2F+jd0H xfGLVuAJTOJAjMEAAEIAB0WIQTEOAw+ll79gQef86f6PaqMvJYe9QUCZMzXegAKCRD6PaqMvJYe 9SAnD/42zhCeSiHSaQ04HYuQVR134RabhRuzmMjSbljYZOMS0jIIWPwPNPHxxU3+zAyYYaGj4Mn yhWybHz/BkupsiT4/o9+2zEtmN+bNf6dULlsP82Vdv3jX+2XBl2HWcecUVlpnI+3e4xIWmK1Tbp +2oMqm3Lxui0ryU6rpjnBbm3SxbmLMeE4/kPv13kZjO9SUpoU6afzUirve+LHO8O9Y/1rfsDqvs 0atCeMQAVmB/vcZMHmM8zQZQy3YILkB03M8PpWqEcNN2F24uM5GAmsyMqmQkFOaWtK3QgxMBFSK r1PYEUj8HMFBQfqA6MxDCns/QPvjT8K+yn7mlaLRC4oZVhRVBZZFRe61GTiCu2nAUk7SrK8WR9T 8HLR1koGTidrYoFH+tzvkZZ1Sk3bLhMhc8ucRE60/SnrIhxLfVcYubrrENMzX4cHhSn3NWoxHr0 +7ar3UgmiJYBohwYEgKMPoVMlIrkdDllu/Aos7rKyJwQvbz7hvaR4W9U8tUldn0kjm5ZX5+FK+U ZQwFxMnIiQM4mijTpP94lTYnBg7OsUbz6p1kRmox0qHxX1rsAsVLSsOwbLwe1KSYrNxHEpkKjY5 I4+7dvcTqIQYSCQTzuQdx+jrGausSMLDE/e5bsXRKvJzrjxw4OCa8axVKXpNy14memcm/1I6QI6 aYnhriViYhLissg== X-Developer-Key: i=tomi.valkeinen@ideasonboard.com; a=openpgp; fpr=C4380C3E965EFD81079FF3A7FA3DAA8CBC961EF5 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The lt8912b driver, in its bridge detach function, calls drm_connector_unregister() and drm_connector_cleanup(). drm_connector_unregister() should be called only for connectors explicitly registered with drm_connector_register(), which is not the case in lt8912b. The driver's drm_connector_funcs.destroy hook is set to drm_connector_cleanup(). Thus the driver should not call either drm_connector_unregister() nor drm_connector_cleanup() in its lt8912_bridge_detach(), as they cause a crash on bridge detach: Unable to handle kernel NULL pointer dereference at virtual address 0000000= 000000000 Mem abort info: ESR =3D 0x0000000096000006 EC =3D 0x25: DABT (current EL), IL =3D 32 bits SET =3D 0, FnV =3D 0 EA =3D 0, S1PTW =3D 0 FSC =3D 0x06: level 2 translation fault Data abort info: ISV =3D 0, ISS =3D 0x00000006, ISS2 =3D 0x00000000 CM =3D 0, WnR =3D 0, TnD =3D 0, TagAccess =3D 0 GCS =3D 0, Overlay =3D 0, DirtyBit =3D 0, Xs =3D 0 user pgtable: 4k pages, 48-bit VAs, pgdp=3D00000000858f3000 [0000000000000000] pgd=3D0800000085918003, p4d=3D0800000085918003, pud=3D08= 00000085431003, pmd=3D0000000000000000 Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP Modules linked in: tidss(-) display_connector lontium_lt8912b tc358768 pane= l_lvds panel_simple drm_dma_helper drm_kms_helper drm drm_panel_orientation= _quirks CPU: 3 PID: 462 Comm: rmmod Tainted: G W 6.5.0-rc2+ #2 Hardware name: Toradex Verdin AM62 on Verdin Development Board (DT) pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=3D--) pc : drm_connector_cleanup+0x78/0x2d4 [drm] lr : lt8912_bridge_detach+0x54/0x6c [lontium_lt8912b] sp : ffff800082ed3a90 x29: ffff800082ed3a90 x28: ffff0000040c1940 x27: 0000000000000000 x26: 0000000000000000 x25: dead000000000122 x24: dead000000000122 x23: dead000000000100 x22: ffff000003fb6388 x21: 0000000000000000 x20: 0000000000000000 x19: ffff000003fb6260 x18: fffffffffffe56e8 x17: 0000000000000000 x16: 0010000000000000 x15: 0000000000000038 x14: 0000000000000000 x13: ffff800081914b48 x12: 000000000000040e x11: 000000000000015a x10: ffff80008196ebb8 x9 : ffff800081914b48 x8 : 00000000ffffefff x7 : ffff0000040c1940 x6 : ffff80007aa649d0 x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008159e008 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: drm_connector_cleanup+0x78/0x2d4 [drm] lt8912_bridge_detach+0x54/0x6c [lontium_lt8912b] drm_bridge_detach+0x44/0x84 [drm] drm_encoder_cleanup+0x40/0xb8 [drm] drmm_encoder_alloc_release+0x1c/0x30 [drm] drm_managed_release+0xac/0x148 [drm] drm_dev_put.part.0+0x88/0xb8 [drm] devm_drm_dev_init_release+0x14/0x24 [drm] devm_action_release+0x14/0x20 release_nodes+0x5c/0x90 devres_release_all+0x8c/0xe0 device_unbind_cleanup+0x18/0x68 device_release_driver_internal+0x208/0x23c driver_detach+0x4c/0x94 bus_remove_driver+0x70/0xf4 driver_unregister+0x30/0x60 platform_driver_unregister+0x14/0x20 tidss_platform_driver_exit+0x18/0xb2c [tidss] __arm64_sys_delete_module+0x1a0/0x2b4 invoke_syscall+0x48/0x110 el0_svc_common.constprop.0+0x60/0x10c do_el0_svc_compat+0x1c/0x40 el0_svc_compat+0x40/0xac el0t_32_sync_handler+0xb0/0x138 el0t_32_sync+0x194/0x198 Code: 9104a276 f2fbd5b7 aa0203e1 91008af8 (f85c0420) Fixes: 30e2ae943c26 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge") Signed-off-by: Tomi Valkeinen Reviewed-by: Robert Foss --- drivers/gpu/drm/bridge/lontium-lt8912b.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c b/drivers/gpu/drm/bri= dge/lontium-lt8912b.c index 0e581f6e3c88..2d752e083433 100644 --- a/drivers/gpu/drm/bridge/lontium-lt8912b.c +++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c @@ -589,9 +589,6 @@ static void lt8912_bridge_detach(struct drm_bridge *bri= dge) =20 if (lt->hdmi_port->ops & DRM_BRIDGE_OP_HPD) drm_bridge_hpd_disable(lt->hdmi_port); - - drm_connector_unregister(<->connector); - drm_connector_cleanup(<->connector); } =20 static enum drm_connector_status --=20 2.34.1