From nobody Fri Dec 19 18:41:46 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 9C116C67871 for ; Mon, 24 Oct 2022 20:56:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235184AbiJXU40 (ORCPT ); Mon, 24 Oct 2022 16:56:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233989AbiJXU4D (ORCPT ); Mon, 24 Oct 2022 16:56:03 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 495562C4C9E; Mon, 24 Oct 2022 12:02:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E8CB1B815B4; Mon, 24 Oct 2022 12:10:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4930DC43142; Mon, 24 Oct 2022 12:10:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613408; bh=G1iDAf3f6Jpdzk94UbQC3Rkti0Ys811hQbx2+MSiH9k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CuPfMEny0Ift32isBMGhUf5Sb8cc6xfGJa3gcHy3iLipCswGQZ2pl8DhXaq8Aroxd DcV6cKisSGwUm6ZlY2C+3WwXBBkfBWYmwW7e1YZqVWib86lAm7322XgW8Z0ETNfzsW ZypnnrzQH1BF4mDYNLY64oW0T7iCggLKT47TUEAQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zheyu Ma , Robert Foss , Sasha Levin Subject: [PATCH 5.4 095/255] drm/bridge: megachips: Fix a null pointer dereference bug Date: Mon, 24 Oct 2022 13:30:05 +0200 Message-Id: <20221024113005.647585310@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113002.471093005@linuxfoundation.org> References: <20221024113002.471093005@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Zheyu Ma [ Upstream commit 1ff673333d46d2c1b053ebd0c1c7c7c79e36943e ] When removing the module we will get the following warning: [ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered [ 31.912484] general protection fault, probably for non-canonical address= 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI [ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-0x0000000= 00000000f] [ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130 [ 31.921825] Call Trace: [ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60 [megachips_stdpxxxx_= ge_b850v3_fw] [ 31.923139] i2c_device_remove+0x181/0x1f0 The two bridges (stdp2690, stdp4028) do not probe at the same time, so the driver does not call ge_b850v3_resgiter() when probing, causing the driver to try to remove the object that has not been initialized. Fix this by checking whether both the bridges are probed. Fixes: 11632d4aa2b3 ("drm/bridge: megachips: Ensure both bridges are probed= before registration") Signed-off-by: Zheyu Ma Signed-off-by: Robert Foss Link: https://patchwork.freedesktop.org/patch/msgid/20220830073450.1897020-= 1-zheyuma97@gmail.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/dri= vers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c index 5302dd90a7a5..b72f6f541d4e 100644 --- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c +++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c @@ -279,7 +279,9 @@ static void ge_b850v3_lvds_remove(void) * This check is to avoid both the drivers * removing the bridge in their remove() function */ - if (!ge_b850v3_lvds_ptr) + if (!ge_b850v3_lvds_ptr || + !ge_b850v3_lvds_ptr->stdp2690_i2c || + !ge_b850v3_lvds_ptr->stdp4028_i2c) goto out; =20 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge); --=20 2.35.1