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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A633DC77B7F for ; Mon, 8 May 2023 09:58:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233855AbjEHJ6c (ORCPT ); Mon, 8 May 2023 05:58:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233137AbjEHJ6c (ORCPT ); Mon, 8 May 2023 05:58:32 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B56E2B17C for ; Mon, 8 May 2023 02:58:31 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 9126F62284 for ; Mon, 8 May 2023 09:58:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C03BC433D2; Mon, 8 May 2023 09:58:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1683539910; bh=CCBSryebc3uG0PaVN6xbha/mpSyz4nZJ2v/CDUz5eMk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P7r9AmGqW6UEA6Dty1Lmt25mkOarR8u7pEoVt46Jbv7B98Q5ylkBjFvGaGOI+W1ye 0O4gwkp5NV0TvJ8++7lf4S8wJauAbPp5IyQ9dgRf2eIcujQVCZsahBDolY6fYw2crZ kjBPC26vouhjS03aLVmAF9NnuPdykcmvxvJWJKK4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chen-Yu Tsai , Guillaume Ranquet , AngeloGioacchino Del Regno , Matthias Brugger , Chun-Kuang Hu , Sasha Levin Subject: [PATCH 6.1 144/611] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached Date: Mon, 8 May 2023 11:39:46 +0200 Message-Id: <20230508094426.913201100@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230508094421.513073170@linuxfoundation.org> References: <20230508094421.513073170@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chen-Yu Tsai [ Upstream commit 36b617f7e4ae663fcadd202ea061ca695ca75539 ] The MediaTek DisplayPort interface bridge driver starts its interrupts as soon as its probed. However when the interrupts trigger the bridge might not have been attached to a DRM device. As drm_helper_hpd_irq_event() does not check whether the passed in drm_device is valid or not, a NULL pointer passed in results in a kernel NULL pointer dereference in it. Check whether the bridge is attached and only trigger an HPD event if it is. Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver") Signed-off-by: Chen-Yu Tsai Reviewed-by: Guillaume Ranquet Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: Matthias Brugger Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20230202045734.2773503-1-wenst@chromium.org/ Signed-off-by: Chun-Kuang Hu Signed-off-by: Sasha Levin --- drivers/gpu/drm/mediatek/mtk_dp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c index 9d085c05c49c3..d28326350ea93 100644 --- a/drivers/gpu/drm/mediatek/mtk_dp.c +++ b/drivers/gpu/drm/mediatek/mtk_dp.c @@ -1823,7 +1823,8 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev) spin_unlock_irqrestore(&mtk_dp->irq_thread_lock, flags); if (status & MTK_DP_THREAD_CABLE_STATE_CHG) { - drm_helper_hpd_irq_event(mtk_dp->bridge.dev); + if (mtk_dp->bridge.dev) + drm_helper_hpd_irq_event(mtk_dp->bridge.dev); if (!mtk_dp->train_info.cable_plugged_in) { mtk_dp_disable_sdp_aui(mtk_dp); -- 2.39.2